diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/OS/os.h-Darwin | 4 | ||||
| -rw-r--r-- | src/README.UPDATING | 24 | ||||
| -rw-r--r-- | src/exim_monitor/em_globals.c | 2 | ||||
| -rw-r--r-- | src/src/buildconfig.c | 10 | ||||
| -rw-r--r-- | src/src/exim.h | 4 | ||||
| -rw-r--r-- | src/src/expand.c | 24 | ||||
| -rw-r--r-- | src/src/functions.h | 11 | ||||
| -rw-r--r-- | src/src/globals.c | 2 | ||||
| -rw-r--r-- | src/src/globals.h | 2 | ||||
| -rw-r--r-- | src/src/host.c | 2 | ||||
| -rw-r--r-- | src/src/log.c | 4 | ||||
| -rw-r--r-- | src/src/malware.c | 2 | ||||
| -rw-r--r-- | src/src/readconf.c | 1 | ||||
| -rw-r--r-- | src/src/receive.c | 2 | ||||
| -rw-r--r-- | src/src/smtp_in.c | 8 | ||||
| -rw-r--r-- | src/src/spool_in.c | 4 | ||||
| -rw-r--r-- | src/src/spool_out.c | 2 | ||||
| -rw-r--r-- | src/src/tls-gnu.c | 1809 | ||||
| -rw-r--r-- | src/src/tls-openssl.c | 34 | ||||
| -rw-r--r-- | src/src/tls.c | 6 | ||||
| -rw-r--r-- | src/src/transports/smtp.c | 6 |
21 files changed, 1170 insertions, 793 deletions
diff --git a/src/OS/os.h-Darwin b/src/OS/os.h-Darwin index 888b9c759..af06bdcbc 100644 --- a/src/OS/os.h-Darwin +++ b/src/OS/os.h-Darwin @@ -35,4 +35,8 @@ updating Exim to use the newer interface. */ /* It's not .so for dynamic libraries on Darwin. */ #define DYNLIB_FN_EXT "dylib" +/* We currently need some assistance getting OFF_T_FMT correct on MacOS */ +#define OFF_T_FMT "%llu" +#define LONGLONG_T long int + /* End */ diff --git a/src/README.UPDATING b/src/README.UPDATING index 0d729a384..81e767efe 100644 --- a/src/README.UPDATING +++ b/src/README.UPDATING @@ -77,6 +77,30 @@ Exim version 4.78 new option, you can safely force it off before upgrading, to decouple configuration changes from the binary upgrade while remaining RFC compliant. + * The GnuTLS support has been mostly rewritten, to use 2.12.x APIs. As part + of this, these three options are no longer supported: + + gnutls_require_kx + gnutls_require_mac + gnutls_require_protocols + + Their functionality is entirely subsumed into tls_require_ciphers, which is + no longer parsed apart by Exim but is instead given to + gnutls_priority_init(3), which is no longer an Exim list. See: + + http://www.gnu.org/software/gnutls/manual/html_node/Priority-Strings.html + + for fuller documentation of the strings parsed. The three gnutls_require_* + options are still parsed by Exim and, for this release, silently ignored. + A future release will add warnings, before a later still release removes + parsing entirely and the presence of the options will be a configuration + error. + + This rewrite means that Exim will continue to build against GnuTLS in the + future, brings Exim closer to other GnuTLS applications and lets us add + support for SNI and other features more readily. We regret that it wasn't + feasible to retain the three dropped options. + Exim version 4.77 ----------------- diff --git a/src/exim_monitor/em_globals.c b/src/exim_monitor/em_globals.c index 720549382..e74118c45 100644 --- a/src/exim_monitor/em_globals.c +++ b/src/exim_monitor/em_globals.c @@ -214,7 +214,7 @@ BOOL timestamps_utc = FALSE; BOOL tls_certificate_verified = FALSE; uschar *tls_cipher = NULL; uschar *tls_peerdn = NULL; -#ifndef USE_GNUTLS +#ifdef SUPPORT_TLS uschar *tls_sni = NULL; #endif diff --git a/src/src/buildconfig.c b/src/src/buildconfig.c index 64902a1ee..1eaf2f505 100644 --- a/src/src/buildconfig.c +++ b/src/src/buildconfig.c @@ -103,6 +103,7 @@ off_t test_off_t = 0; time_t test_time_t = 0; #if ! (__STDC_VERSION__ >= 199901L) size_t test_size_t = 0; +ssize_t test_ssize_t = 0; unsigned long test_ulong_t = 0L; #endif long test_long_t = 0; @@ -179,15 +180,22 @@ else fprintf(new, "#endif\n\n"); /* And for sizeof() results, size_t, which should with C99 be just %zu, deal -with C99 not being ubiquitous yet. Unfortunately. */ +with C99 not being ubiquitous yet. Unfortunately. Assume ssize_t is same +size as size_t on C99; if someone comes up with a version where it's not, fix +it then. */ #if __STDC_VERSION__ >= 199901L fprintf(new, "#define SIZE_T_FMT \"%%zu\"\n"); +fprintf(new, "#define SSIZE_T_FMT \"%%zd\"\n"); #else if (sizeof(test_size_t) > sizeof (test_ulong_t)) fprintf(new, "#define SIZE_T_FMT \"%%llu\"\n"); else fprintf(new, "#define SIZE_T_FMT \"%%lu\"\n"); +if (sizeof(test_ssize_t) > sizeof(test_long_t)) + fprintf(new, "#define SSIZE_T_FMT \"%%lld\"\n"); +else + fprintf(new, "#define SSIZE_T_FMT \"%%ld\"\n"); #endif /* Now search the makefile for certain settings */ diff --git a/src/src/exim.h b/src/src/exim.h index e6e72facc..49f52474a 100644 --- a/src/src/exim.h +++ b/src/src/exim.h @@ -77,6 +77,10 @@ making unique names. */ #include <limits.h> #endif +/* C99 integer types, figure out how to undo this if needed for older systems */ + +#include <inttypes.h> + /* Just in case some aged system doesn't define them... */ #ifndef INT_MAX diff --git a/src/src/expand.c b/src/src/expand.c index dcc813801..2fc953aec 100644 --- a/src/src/expand.c +++ b/src/src/expand.c @@ -615,7 +615,7 @@ static var_entry var_table[] = { { "tls_certificate_verified", vtype_int, &tls_certificate_verified }, { "tls_cipher", vtype_stringptr, &tls_cipher }, { "tls_peerdn", vtype_stringptr, &tls_peerdn }, -#if defined(SUPPORT_TLS) && !defined(USE_GNUTLS) +#ifdef SUPPORT_TLS { "tls_sni", vtype_stringptr, &tls_sni }, #endif { "tod_bsdinbox", vtype_todbsdin, NULL }, @@ -776,6 +776,7 @@ return rc; + /************************************************* * Pseudo-random number generation * *************************************************/ @@ -788,19 +789,23 @@ weirdness they'll twist this into. The result should ideally handle fork(). However, if we're stuck unable to provide this, then we'll fall back to appallingly bad randomness. -If SUPPORT_TLS is defined and OpenSSL is used, then this will not be used. -The GNUTLS randomness functions found do not seem amenable to extracting -random numbers outside of a TLS context. Any volunteers? +If SUPPORT_TLS is defined then this will not be used except as an emergency +fallback. Arguments: max range maximum Returns a random number in range [0, max-1] */ -#if !defined(SUPPORT_TLS) || defined(USE_GNUTLS) +#ifdef SUPPORT_TLS +# define vaguely_random_number vaguely_random_number_fallback +#endif int -pseudo_random_number(int max) +vaguely_random_number(int max) { +#ifdef SUPPORT_TLS +# undef vaguely_random_number +#endif static pid_t pid = 0; pid_t p2; #if defined(HAVE_SRANDOM) && !defined(HAVE_SRANDOMDEV) @@ -843,7 +848,8 @@ pseudo_random_number(int max) #endif } -#endif + + /************************************************* * Pick out a name from a string * @@ -5914,7 +5920,7 @@ while (*s != 0) continue; } - /* pseudo-random number less than N */ + /* vaguely random number less than N */ case EOP_RANDINT: { @@ -5924,7 +5930,7 @@ while (*s != 0) max = expand_string_integer(sub, TRUE); if (expand_string_message != NULL) goto EXPAND_FAILED; - s = string_sprintf("%d", pseudo_random_number((int)max)); + s = string_sprintf("%d", vaguely_random_number((int)max)); yield = string_cat(yield, &size, &ptr, s, Ustrlen(s)); continue; } diff --git a/src/src/functions.h b/src/src/functions.h index 8986f3a49..557b7e72a 100644 --- a/src/src/functions.h +++ b/src/src/functions.h @@ -23,13 +23,13 @@ extern uschar *init_perl(uschar *); #ifdef SUPPORT_TLS extern int tls_client_start(int, host_item *, address_item *, uschar *, uschar *, uschar *, uschar *, uschar *, uschar *, uschar *, - uschar *, uschar *, uschar *, int); + int); extern void tls_close(BOOL); extern int tls_feof(void); extern int tls_ferror(void); extern int tls_getc(void); extern int tls_read(uschar *, size_t); -extern int tls_server_start(uschar *, uschar *, uschar *, uschar *); +extern int tls_server_start(const uschar *); extern BOOL tls_smtp_buffered(void); extern int tls_ungetc(int); extern int tls_write(const uschar *, size_t); @@ -199,7 +199,10 @@ extern uschar *parse_fix_phrase(uschar *, int, uschar *, int); extern uschar *parse_message_id(uschar *, uschar **, uschar **); extern uschar *parse_quote_2047(uschar *, int, uschar *, uschar *, int, BOOL); extern uschar *parse_date_time(uschar *str, time_t *t); -extern int pseudo_random_number(int); +extern int vaguely_random_number(int); +#ifdef SUPPORT_TLS +extern int vaguely_random_number_fallback(int); +#endif extern BOOL queue_action(uschar *, int, uschar **, int, int); extern void queue_check_only(void); @@ -379,4 +382,6 @@ extern BOOL verify_sender(int *, uschar **); extern BOOL verify_sender_preliminary(int *, uschar **); extern void version_init(void); +extern ssize_t write_to_fd_buf(int, const uschar *, size_t); + /* End of functions.h */ diff --git a/src/src/globals.c b/src/src/globals.c index b68544e54..d341ceb4a 100644 --- a/src/src/globals.c +++ b/src/src/globals.c @@ -116,9 +116,7 @@ BOOL tls_offered = FALSE; uschar *tls_privatekey = NULL; BOOL tls_remember_esmtp = FALSE; uschar *tls_require_ciphers = NULL; -#ifndef USE_GNUTLS uschar *tls_sni = NULL; -#endif uschar *tls_try_verify_hosts = NULL; uschar *tls_verify_certificates= NULL; uschar *tls_verify_hosts = NULL; diff --git a/src/src/globals.h b/src/src/globals.h index d267a52b7..37b0f6cf0 100644 --- a/src/src/globals.h +++ b/src/src/globals.h @@ -98,9 +98,7 @@ extern BOOL tls_offered; /* Server offered TLS */ extern uschar *tls_privatekey; /* Private key file */ extern BOOL tls_remember_esmtp; /* For YAEB */ extern uschar *tls_require_ciphers; /* So some can be avoided */ -#ifndef USE_GNUTLS extern uschar *tls_sni; /* Server Name Indication */ -#endif extern uschar *tls_try_verify_hosts; /* Optional client verification */ extern uschar *tls_verify_certificates;/* Path for certificates to check */ extern uschar *tls_verify_hosts; /* Mandatory client verification */ diff --git a/src/src/host.c b/src/src/host.c index 0571772cb..c45c2d77b 100644 --- a/src/src/host.c +++ b/src/src/host.c @@ -68,7 +68,7 @@ sprintf(addr, "%d.%d.%d.%d", very good for the uses to which it is put. When running the regression tests, start with a fixed seed. -If you need better, see pseudo_random_number() which is potentially stronger, +If you need better, see vaguely_random_number() which is potentially stronger, if a crypto library is available, but might end up just calling this instead. Arguments: diff --git a/src/src/log.c b/src/src/log.c index 75285c136..0ba4e638b 100644 --- a/src/src/log.c +++ b/src/src/log.c @@ -528,11 +528,11 @@ Returns: length actually written, persisting an errno from write() */ ssize_t -write_to_fd_buf(int fd, uschar *buf, size_t length) +write_to_fd_buf(int fd, const uschar *buf, size_t length) { ssize_t wrote; size_t total_written = 0; -uschar *p = buf; +const uschar *p = buf; size_t left = length; while (1) diff --git a/src/src/malware.c b/src/src/malware.c index 864564ffc..79e2e3827 100644 --- a/src/src/malware.c +++ b/src/src/malware.c @@ -115,7 +115,7 @@ malware_in_file(uschar *eml_filename) { /* spool_mbox() assumes various parameters exist, when creating the relevant directory and the email within */ (void) string_format(message_id_buf, sizeof(message_id_buf), - "dummy-%d", pseudo_random_number(INT_MAX)); + "dummy-%d", vaguely_random_number(INT_MAX)); message_id = message_id_buf; sender_address = US"malware-sender@example.net"; return_path = US""; diff --git a/src/src/readconf.c b/src/src/readconf.c index b35811e48..cdd32be58 100644 --- a/src/src/readconf.c +++ b/src/src/readconf.c @@ -235,6 +235,7 @@ static optionlist optionlist_config[] = { { "gecos_pattern", opt_stringptr, &gecos_pattern }, #ifdef SUPPORT_TLS { "gnutls_compat_mode", opt_bool, &gnutls_compat_mode }, + /* These three gnutls_require_* options stopped working in Exim 4.78 */ { "gnutls_require_kx", opt_stringptr, &gnutls_require_kx }, { "gnutls_require_mac", opt_stringptr, &gnutls_require_mac }, { "gnutls_require_protocols", opt_stringptr, &gnutls_require_proto }, diff --git a/src/src/receive.c b/src/src/receive.c index aaaf64ce6..b3b06e867 100644 --- a/src/src/receive.c +++ b/src/src/receive.c @@ -3488,12 +3488,10 @@ if ((log_extra_selector & LX_tls_certificate_verified) != 0 && if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_peerdn != NULL) s = string_append(s, &size, &sptr, 3, US" DN=\"", string_printing(tls_peerdn), US"\""); -#ifndef USE_GNUTLS if ((log_extra_selector & LX_tls_sni) != 0 && tls_sni != NULL) s = string_append(s, &size, &sptr, 3, US" SNI=\"", string_printing(tls_sni), US"\""); #endif -#endif if (sender_host_authenticated != NULL) { diff --git a/src/src/smtp_in.c b/src/src/smtp_in.c index d1c10f00f..5d241d960 100644 --- a/src/src/smtp_in.c +++ b/src/src/smtp_in.c @@ -841,12 +841,10 @@ if ((log_extra_selector & LX_tls_certificate_verified) != 0 && if ((log_extra_selector & LX_tls_peerdn) != 0 && tls_peerdn != NULL) s = string_append(s, &size, &ptr, 3, US" DN=\"", string_printing(tls_peerdn), US"\""); -#ifndef USE_GNUTLS if ((log_extra_selector & LX_tls_sni) != 0 && tls_sni != NULL) s = string_append(s, &size, &ptr, 3, US" SNI=\"", string_printing(tls_sni), US"\""); #endif -#endif sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)? US" C=..." : US" C="; @@ -1676,8 +1674,7 @@ if (!sender_host_unknown) #ifdef SUPPORT_TLS if (tls_on_connect && - tls_server_start(tls_require_ciphers, - gnutls_require_mac, gnutls_require_kx, gnutls_require_proto) != OK) + tls_server_start(tls_require_ciphers) != OK) return FALSE; #endif @@ -3893,8 +3890,7 @@ while (done <= 0) We must allow for an extra EHLO command and an extra AUTH command after STARTTLS that don't add to the nonmail command count. */ - if ((rc = tls_server_start(tls_require_ciphers, gnutls_require_mac, - gnutls_require_kx, gnutls_require_proto)) == OK) + if ((rc = tls_server_start(tls_require_ciphers)) == OK) { if (!tls_remember_esmtp) helo_seen = esmtp = auth_advertised = pipelining_advertised = FALSE; diff --git a/src/src/spool_in.c b/src/src/spool_in.c index bdc3903c0..f6aa18c34 100644 --- a/src/src/spool_in.c +++ b/src/src/spool_in.c @@ -286,10 +286,8 @@ dkim_collect_input = FALSE; tls_certificate_verified = FALSE; tls_cipher = NULL; tls_peerdn = NULL; -#ifndef USE_GNUTLS tls_sni = NULL; #endif -#endif #ifdef WITH_CONTENT_SCAN spam_score_int = NULL; @@ -552,10 +550,8 @@ for (;;) tls_cipher = string_copy(big_buffer + 12); else if (Ustrncmp(p, "ls_peerdn", 9) == 0) tls_peerdn = string_unprinting(string_copy(big_buffer + 12)); - #ifndef USE_GNUTLS else if (Ustrncmp(p, "ls_sni", 6) == 0) tls_sni = string_unprinting(string_copy(big_buffer + 9)); - #endif break; #endif diff --git a/src/src/spool_out.c b/src/src/spool_out.c index fa4f1b6e2..0d32fd6ca 100644 --- a/src/src/spool_out.c +++ b/src/src/spool_out.c @@ -229,10 +229,8 @@ if (bmi_verdicts != NULL) fprintf(f, "-bmi_verdicts %s\n", bmi_verdicts); if (tls_certificate_verified) fprintf(f, "-tls_certificate_verified\n"); if (tls_cipher != NULL) fprintf(f, "-tls_cipher %s\n", tls_cipher); if (tls_peerdn != NULL) fprintf(f, "-tls_peerdn %s\n", string_printing(tls_peerdn)); -#ifndef USE_GNUTLS if (tls_sni != NULL) fprintf(f, "-tls_sni %s\n", string_printing(tls_sni)); #endif -#endif /* To complete the envelope, write out the tree of non-recipients, followed by the list of recipients. These won't be disjoint the first time, when no diff --git a/src/src/tls-gnu.c b/src/src/tls-gnu.c index 7e87dded0..f0e391f97 100644 --- a/src/src/tls-gnu.c +++ b/src/src/tls-gnu.c @@ -2,178 +2,178 @@ * Exim - an Internet mail transport agent * *************************************************/ -/* Copyright (c) University of Cambridge 1995 - 2009 */ +/* Copyright (c) University of Cambridge 1995 - 2012 */ /* See the file NOTICE for conditions of use and distribution. */ -/* This module provides TLS (aka SSL) support for Exim using the GnuTLS -library. It is #included into tls.c when that library is used. The code herein -is based on a patch that was contributed by Nikos Mavroyanopoulos. +/* Copyright (c) Phil Pennock 2012 */ -No cryptographic code is included in Exim. All this module does is to call -functions from the GnuTLS library. */ +/* This file provides TLS/SSL support for Exim using the GnuTLS library, +one of the available supported implementations. This file is #included into +tls.c when USE_GNUTLS has been set. -/* Note: This appears to be using an old API from compat.h; it is likely that -someone familiary with GnuTLS programming could rework a lot of this to a -modern API and perhaps remove the explicit knowledge of crypto algorithms from -Exim. Such a re-work would be most welcome and we'd sacrifice support for -older GnuTLS releases without too many qualms -- maturity and experience -in crypto libraries tends to improve their robustness against attack. -Frankly, if you maintain it, you decide what's supported and what isn't. */ +The code herein is a revamp of GnuTLS integration using the current APIs; the +original tls-gnu.c was based on a patch which was contributed by Nikos +Mavroyanopoulos. The revamp is partially a rewrite, partially cut&paste as +appropriate. -/* Heading stuff for GnuTLS */ +APIs current as of GnuTLS 2.12.18; note that the GnuTLS manual is for GnuTLS 3, +which is not widely deployed by OS vendors. Will note issues below, which may +assist in updating the code in the future. Another sources of hints is +mod_gnutls for Apache (SNI callback registration and handling). -#include <gnutls/gnutls.h> -#include <gnutls/x509.h> +Keeping client and server variables more split than before and is currently +the norm, in anticipation of TLS in ACL callouts. +I wanted to switch to gnutls_certificate_set_verify_function() so that +certificate rejection could happen during handshake where it belongs, rather +than being dropped afterwards, but that was introduced in 2.10.0 and Debian +(6.0.5) is still on 2.8.6. So for now we have to stick with sub-par behaviour. -#define UNKNOWN_NAME "unknown" -#define DH_BITS 1024 -#define PARAM_SIZE 2*1024 +(I wasn't looking for libraries quite that old, when updating to get rid of +compiler warnings of deprecated APIs. If it turns out that a lot of the rest +require current GnuTLS, then we'll drop support for the ancient libraries). +*/ +#include <gnutls/gnutls.h> +/* needed for cert checks in verification and DN extraction: */ +#include <gnutls/x509.h> +/* man-page is incorrect, gnutls_rnd() is not in gnutls.h: */ +#include <gnutls/crypto.h> -/* Values for verify_requirment */ +/* GnuTLS 2 vs 3 -enum { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED }; +GnuTLS 3 only: + gnutls_global_set_audit_log_function() -/* Local static variables for GNUTLS */ +Changes: + gnutls_certificate_verify_peers2(): is new, drop the 2 for old version +*/ -static host_item *client_host; +/* Local static variables for GnuTLS */ -static gnutls_dh_params dh_params = NULL; +/* Values for verify_requirement */ -static gnutls_certificate_server_credentials x509_cred = NULL; -static gnutls_session tls_session = NULL; +enum peer_verify_requirement { VERIFY_NONE, VERIFY_OPTIONAL, VERIFY_REQUIRED }; -static char ssl_errstring[256]; +/* This holds most state for server or client; with this, we can set up an +outbound TLS-enabled connection in an ACL callout, while not stomping all +over the TLS variables available for expansion. -static int ssl_session_timeout = 200; -static int verify_requirement; +Some of these correspond to variables in globals.c; those variables will +be set to point to content in one of these instances, as appropriate for +the stage of the process lifetime. -/* Priorities for TLS algorithms to use. In each case there's a default table, -and space into which it can be copied and altered. */ +Not handled here: globals tls_active, tls_bits, tls_cipher, tls_peerdn, +tls_certificate_verified, tls_channelbinding_b64, tls_sni. +*/ -static const int default_proto_priority[16] = { - /* These are gnutls_protocol_t enum values */ -#if GNUTLS_VERSION_MAJOR > 1 || GNUTLS_VERSION_MINOR >= 7 - GNUTLS_TLS1_2, -#endif -#if GNUTLS_VERSION_MAJOR > 1 || GNUTLS_VERSION_MINOR >= 2 - GNUTLS_TLS1_1, -#endif - GNUTLS_TLS1, - GNUTLS_SSL3, - 0 }; +typedef struct exim_gnutls_state { + gnutls_session_t session; + gnutls_certificate_credentials_t x509_cred; + gnutls_priority_t priority_cache; + enum peer_verify_requirement verify_requirement; + int fd_in; + int fd_out; + BOOL peer_cert_verified; + BOOL trigger_sni_changes; + const struct host_item *host; + uschar *peerdn; + uschar *received_sni; + + const uschar *tls_certificate; + const uschar *tls_privatekey; + const uschar *tls_sni; /* client send only, not received */ + const uschar *tls_verify_certificates; + const uschar *tls_crl; + const uschar *tls_require_ciphers; + uschar *exp_tls_certificate; + uschar *exp_tls_privatekey; + uschar *exp_tls_sni; + uschar *exp_tls_verify_certificates; + uschar *exp_tls_crl; + uschar *exp_tls_require_ciphers; + + uschar *xfer_buffer; + int xfer_buffer_lwm; + int xfer_buffer_hwm; + int xfer_eof; + int xfer_error; + + uschar cipherbuf[256]; +} exim_gnutls_state_st; + +static const exim_gnutls_state_st exim_gnutls_state_init = { + NULL, NULL, NULL, VERIFY_NONE, -1, -1, FALSE, FALSE, + NULL, NULL, NULL, + NULL, NULL, NULL, NULL, NULL, NULL, + NULL, NULL, NULL, NULL, NULL, NULL, + NULL, 0, 0, 0, 0, + "" +}; -static int proto_priority[16]; +/* Not only do we have our own APIs which don't pass around state, assuming +it's held in globals, GnuTLS doesn't appear to let us register callback data +for callbacks, or as part of the session, so we have to keep a "this is the +context we're currently dealing with" pointer and rely upon being +single-threaded to keep from processing data on an inbound TLS connection while +talking to another TLS connection for an outbound check. This does mean that +there's no way for heart-beats to be responded to, for the duration of the +second connection. */ -static const int default_kx_priority[16] = { - GNUTLS_KX_RSA, - GNUTLS_KX_DHE_DSS, - GNUTLS_KX_DHE_RSA, - 0 }; +static exim_gnutls_state_st state_server, state_client; +static exim_gnutls_state_st *current_global_tls_state; -static int kx_priority[16]; +/* dh_params are initialised once within the lifetime of a process using TLS; +if we used TLS in a long-lived daemon, we'd have to reconsider this. But we +don't want to repeat this. */ -static int default_cipher_priority[16] = { - GNUTLS_CIPHER_AES_256_CBC, - GNUTLS_CIPHER_AES_128_CBC, - GNUTLS_CIPHER_3DES_CBC, - GNUTLS_CIPHER_ARCFOUR_128, - 0 }; +static gnutls_dh_params_t dh_server_params = NULL; -static int cipher_priority[16]; +/* No idea how this value was chosen; preserving it. Default is 3600. */ -static const int default_mac_priority[16] = { - GNUTLS_MAC_SHA, - GNUTLS_MAC_MD5, - 0 }; +static const int ssl_session_timeout = 200; -static int mac_priority[16]; +static const char * const exim_default_gnutls_priority = "NORMAL"; -/* These two are currently not changeable. */ +/* Guard library core initialisation */ -static const int comp_priority[16] = { GNUTLS_COMP_NULL, 0 }; -static const int cert_type_priority[16] = { GNUTLS_CRT_X509, 0 }; +static BOOL exim_gnutls_base_init_done = FALSE; -/* Tables of priority names and equivalent numbers */ -typedef struct pri_item { - uschar *name; - int *values; -} pri_item; +/* ------------------------------------------------------------------------ */ +/* Callback declarations */ +static void exim_gnutls_logger_cb(int level, const char *message); +static int exim_sni_handling_cb(gnutls_session_t session); -#if GNUTLS_VERSION_MAJOR > 1 || GNUTLS_VERSION_MINOR >= 7 -static int tls1_2_codes[] = { GNUTLS_TLS1_2, 0 }; -#endif -#if GNUTLS_VERSION_MAJOR > 1 || GNUTLS_VERSION_MINOR >= 2 -static int tls1_1_codes[] = { GNUTLS_TLS1_1, 0 }; -#endif -/* more recent libraries define this as an equivalent value to the -canonical GNUTLS_TLS1_0; since they're the same, we stick to the -older name. */ -static int tls1_0_codes[] = { GNUTLS_TLS1, 0 }; -static int ssl3_codes[] = { GNUTLS_SSL3, 0 }; - -static pri_item proto_index[] = { -#if GNUTLS_VERSION_MAJOR > 1 || GNUTLS_VERSION_MINOR >= 7 - { US"TLS1.2", tls1_2_codes }, -#endif -#if GNUTLS_VERSION_MAJOR > 1 || GNUTLS_VERSION_MINOR >= 2 - { US"TLS1.1", tls1_1_codes }, -#endif - { US"TLS1.0", tls1_0_codes }, - { US"TLS1", tls1_0_codes }, - { US"SSL3", ssl3_codes } -}; +/* ------------------------------------------------------------------------ */ +/* macros */ +#define MAX_HOST_LEN 255 -static int kx_rsa_codes[] = { GNUTLS_KX_RSA, - GNUTLS_KX_DHE_RSA, 0 }; -static int kx_dhe_codes[] = { GNUTLS_KX_DHE_DSS, - GNUTLS_KX_DHE_RSA, 0 }; -static int kx_dhe_dss_codes[] = { GNUTLS_KX_DHE_DSS, 0 }; -static int kx_dhe_rsa_codes[] = { GNUTLS_KX_DHE_RSA, 0 }; - -static pri_item kx_index[] = { - { US"DHE_DSS", kx_dhe_dss_codes }, - { US"DHE_RSA", kx_dhe_rsa_codes }, - { US"RSA", kx_rsa_codes }, - { US"DHE", kx_dhe_codes } -}; +/* Set this to control gnutls_global_set_log_level(); values 0 to 9 will setup +the library logging; a value less than 0 disables the calls to set up logging +callbacks. */ +#define EXIM_GNUTLS_LIBRARY_LOG_LEVEL -1 +#define EXIM_CLIENT_DH_MIN_BITS 1024 -static int arcfour_128_codes[] = { GNUTLS_CIPHER_ARCFOUR_128, 0 }; -static int arcfour_40_codes[] = { GNUTLS_CIPHER_ARCFOUR_40, 0 }; -static int arcfour_codes[] = { GNUTLS_CIPHER_ARCFOUR_128, - GNUTLS_CIPHER_ARCFOUR_40, 0 }; -static int aes_256_codes[] = { GNUTLS_CIPHER_AES_256_CBC, 0 }; -static int aes_128_codes[] = { GNUTLS_CIPHER_AES_128_CBC, 0 }; -static int aes_codes[] = { GNUTLS_CIPHER_AES_256_CBC, - GNUTLS_CIPHER_AES_128_CBC, 0 }; -static int des3_codes[] = { GNUTLS_CIPHER_3DES_CBC, 0 }; - -static pri_item cipher_index[] = { - { US"ARCFOUR_128", arcfour_128_codes }, - { US"ARCFOUR_40", arcfour_40_codes }, - { US"ARCFOUR", arcfour_codes }, - { US"AES_256", aes_256_codes }, - { US"AES_128", aes_128_codes }, - { US"AES", aes_codes }, - { US"3DES", des3_codes } -}; +#define exim_gnutls_err_check(Label) do { \ + if (rc != GNUTLS_E_SUCCESS) { return tls_error((Label), gnutls_strerror(rc), host); } } while (0) +#define exim_gnutls_err_debugreturn0(Label) do { \ + if (rc != GNUTLS_E_SUCCESS) { \ + DEBUG(D_tls) debug_printf("TLS failure: %s: %s", (Label), gnutls_strerror(rc)); \ + return 0; } } while (0) -static int mac_sha_codes[] = { GNUTLS_MAC_SHA, 0 }; -static int mac_md5_codes[] = { GNUTLS_MAC_MD5, 0 }; - -static pri_item mac_index[] = { - { US"SHA", mac_sha_codes }, - { US"SHA1", mac_sha_codes }, - { US"MD5", mac_md5_codes } -}; +#define expand_check_tlsvar(Varname) expand_check(state->Varname, US #Varname, &state->exp_##Varname) +#if GNUTLS_VERSION_NUMBER >= 0x020c00 +#define HAVE_GNUTLS_SESSION_CHANNEL_BINDING +#endif +/* ------------------------------------------------------------------------ */ +/* Static functions */ /************************************************* * Handle TLS error * @@ -188,120 +188,169 @@ some shared functions. Argument: prefix text to include in the logged error - host NULL if setting up a server; - the connected host if setting up a client msg additional error string (may be NULL) usually obtained from gnutls_strerror() + host NULL if setting up a server; + the connected host if setting up a client Returns: OK/DEFER/FAIL */ static int -tls_error(uschar *prefix, host_item *host, const char *msg) +tls_error(const uschar *prefix, const char *msg, const host_item *host) { -if (host == NULL) +if (host) + { + log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s)%s%s", + host->name, host->address, prefix, msg ? ": " : "", msg ? msg : ""); + return FAIL; + } +else { uschar *conn_info = smtp_get_connection_info(); - if (strncmp(conn_info, "SMTP ", 5) == 0) + if (Ustrncmp(conn_info, US"SMTP ", 5) == 0) conn_info += 5; log_write(0, LOG_MAIN, "TLS error on %s (%s)%s%s", - conn_info, prefix, msg ? ": " : "", msg ? msg : ""); + conn_info, prefix, msg ? ": " : "", msg ? msg : ""); return DEFER; } -else - { - log_write(0, LOG_MAIN, "TLS error on connection to %s [%s] (%s)%s%s", - host->name, host->address, prefix, msg ? ": " : "", msg ? msg : ""); - return FAIL; - } } + /************************************************* -* Verify certificate * +* Deal with logging errors during I/O * *************************************************/ -/* Called after a successful handshake, when certificate verification is -required or optional, for both server and client. +/* We have to get the identity of the peer from saved data. -Arguments: - session GNUTLS session - error where to put text giving a reason for failure +Argument: + state the current GnuTLS exim state container + rc the GnuTLS error code, or 0 if it's a local error + when text identifying read or write + text local error text when ec is 0 -Returns: TRUE/FALSE +Returns: nothing */ -static BOOL -verify_certificate(gnutls_session session, const char **error) +static void +record_io_error(exim_gnutls_state_st *state, int rc, uschar *when, uschar *text) { -int rc = -1; -uschar *dn_string = US""; -const gnutls_datum *cert; -unsigned int verify, cert_size = 0; +const char *msg; -*error = NULL; +if (rc == GNUTLS_E_FATAL_ALERT_RECEIVED) + msg = CS string_sprintf("%s: %s", US gnutls_strerror(rc), + US gnutls_alert_get_name(gnutls_alert_get(state->session))); +else + msg = gnutls_strerror(rc); -/* Get the peer's certificate. If it sent one, extract it's DN, and then -attempt to verify the certificate. If no certificate is supplied, verification -is forced to fail. */ +tls_error(when, msg, state->host); +} -cert = gnutls_certificate_get_peers(session, &cert_size); -if (cert != NULL) - { - uschar buff[1024]; - gnutls_x509_crt gcert; - gnutls_x509_crt_init(&gcert); - dn_string = US"unknown"; - if (gnutls_x509_crt_import(gcert, cert, GNUTLS_X509_FMT_DER) == 0) - { - size_t bufsize = sizeof(buff); - if (gnutls_x509_crt_get_dn(gcert, CS buff, &bufsize) >= 0) - dn_string = string_copy_malloc(buff); - } - rc = gnutls_certificate_verify_peers2(session, &verify); - } -else - { - DEBUG(D_tls) debug_printf("no peer certificate supplied\n"); - verify = GNUTLS_CERT_INVALID; - *error = "not supplied"; - } +/************************************************* +* Set various Exim expansion vars * +*************************************************/ -/* Handle the result of verification. INVALID seems to be set as well -as REVOKED, but leave the test for both. */ +/* We set various Exim global variables from the state, once a session has +been established. With TLS callouts, may need to change this to stack +variables, or just re-call it with the server state after client callout +has finished. -if ((rc < 0) || (verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)) != 0) - { - tls_certificate_verified = FALSE; - if (*error == NULL) *error = ((verify & GNUTLS_CERT_REVOKED) != 0)? - "revoked" : "invalid"; - if (verify_requirement == VERIFY_REQUIRED) - { - DEBUG(D_tls) debug_printf("TLS certificate verification failed (%s): " - "peerdn=%s\n", *error, dn_string); - gnutls_alert_send(session, GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); - return FALSE; /* reject */ - } - DEBUG(D_tls) debug_printf("TLS certificate verify failure (%s) overridden " - "(host in tls_try_verify_hosts): peerdn=%s\n", *error, dn_string); - } -else +Make sure anything set here is inset in tls_getc(). + +Sets: + tls_active fd + tls_bits strength indicator + tls_certificate_verified bool indicator + tls_channelbinding_b64 for some SASL mechanisms + tls_cipher a string + tls_peerdn a string + tls_sni a (UTF-8) string +Also: + current_global_tls_state for API limitations + +Argument: + state the relevant exim_gnutls_state_st * +*/ + +static void +extract_exim_vars_from_tls_state(exim_gnutls_state_st *state) +{ +gnutls_protocol_t protocol; +gnutls_cipher_algorithm_t cipher; +gnutls_kx_algorithm_t kx; +gnutls_mac_algorithm_t mac; +uschar *p; +#ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING +int old_pool; +int rc; +gnutls_datum_t channel; +#endif + +current_global_tls_state = state; + +tls_active = state->fd_out; + +cipher = gnutls_cipher_get(state->session); +/* returns size in "bytes" */ +tls_bits = gnutls_cipher_get_key_size(cipher) * 8; + +if (!*state->cipherbuf) { - tls_certificate_verified = TRUE; - DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=%s\n", - dn_string); + protocol = gnutls_protocol_get_version(state->session); + mac = gnutls_mac_get(state->session); + kx = gnutls_kx_get(state->session); + + string_format(state->cipherbuf, sizeof(state->cipherbuf), + "%s:%s:%u", + gnutls_protocol_get_name(protocol), + gnutls_cipher_suite_get_name(kx, cipher, mac), + tls_bits); + + /* I don't see a way that spaces could occur, in the current GnuTLS + code base, but it was a concern in the old code and perhaps older GnuTLS + releases did return "TLS 1.0"; play it safe, just in case. */ + for (p = state->cipherbuf; *p != '\0'; ++p) + if (isspace(*p)) + *p = '-'; } +tls_cipher = state->cipherbuf; + +DEBUG(D_tls) debug_printf("cipher: %s\n", tls_cipher); + +tls_certificate_verified = state->peer_cert_verified; -tls_peerdn = dn_string; -return TRUE; /* accept */ +/* note that tls_channelbinding_b64 is not saved to the spool file, since it's +only available for use for authenticators while this TLS session is running. */ + +tls_channelbinding_b64 = NULL; +#ifdef HAVE_GNUTLS_SESSION_CHANNEL_BINDING +channel.data = NULL; +channel.size = 0; +rc = gnutls_session_channel_binding(state->session, GNUTLS_CB_TLS_UNIQUE, &channel); +if (rc) { + DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc)); +} else { + old_pool = store_pool; + store_pool = POOL_PERM; + tls_channelbinding_b64 = auth_b64encode(channel.data, (int)channel.size); + store_pool = old_pool; + DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); +} +#endif + +tls_peerdn = state->peerdn; + +tls_sni = state->received_sni; } + /************************************************* * Setup up DH parameters * *************************************************/ @@ -323,23 +372,30 @@ Returns: OK/DEFER/FAIL */ static int -init_dh(host_item *host) +init_server_dh(void) { -int fd; -int ret; +int fd, rc; +unsigned int dh_bits; gnutls_datum m; -uschar filename[200]; +uschar filename[PATH_MAX]; +size_t sz; +host_item *host = NULL; /* dummy for macros */ +const char * const dh_param_fn_ext = "normal"; /* change as dh_bits changes */ -/* Initialize the data structures for holding the parameters */ +DEBUG(D_tls) debug_printf("Initialising GnuTLS server params.\n"); -ret = gnutls_dh_params_init(&dh_params); -if (ret < 0) return tls_error(US"init dh_params", host, gnutls_strerror(ret)); +rc = gnutls_dh_params_init(&dh_server_params); +exim_gnutls_err_check(US"gnutls_dh_params_init"); -/* Set up the name of the cache file */ +/* If you change this, also change dh_param_fn_ext so that we can use a +different filename and ensure we have sufficient bits. */ +dh_bits = gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_NORMAL); +if (!dh_bits) + return tls_error(US"gnutls_sec_param_to_pk_bits() failed", NULL, NULL); -if (!string_format(filename, sizeof(filename), "%s/gnutls-params", - spool_directory)) - return tls_error(US"overlong filename", host, NULL); +if (!string_format(filename, sizeof(filename), + "%s/gnutls-params-%s", spool_directory, dh_param_fn_ext)) + return tls_error(US"overlong filename", NULL, NULL); /* Open the cache file for reading and if successful, read it and set up the parameters. */ @@ -348,27 +404,50 @@ fd = Uopen(filename, O_RDONLY, 0); if (fd >= 0) { struct stat statbuf; - if (fstat(fd, &statbuf) < 0) + FILE *fp; + int saved_errno; + + if (fstat(fd, &statbuf) < 0) /* EIO */ + { + saved_errno = errno; + (void)close(fd); + return tls_error(US"TLS cache stat failed", strerror(saved_errno), NULL); + } + if (!S_ISREG(statbuf.st_mode)) { (void)close(fd); - return tls_error(US"TLS cache stat failed", host, strerror(errno)); + return tls_error(US"TLS cache not a file", NULL, NULL); + } + fp = fdopen(fd, "rb"); + if (!fp) + { + saved_errno = errno; + (void)close(fd); + return tls_error(US"fdopen(TLS cache stat fd) failed", + strerror(saved_errno), NULL); } m.size = statbuf.st_size; m.data = malloc(m.size); if (m.data == NULL) - return tls_error(US"memory allocation failed", host, strerror(errno)); - errno = 0; - if (read(fd, m.data, m.size) != m.size) - return tls_error(US"TLS cache read failed", host, strerror(errno)); - (void)close(fd); - - ret = gnutls_dh_params_import_pkcs3(dh_params, &m, GNUTLS_X509_FMT_PEM); - if (ret < 0) - return tls_error(US"DH params import", host, gnutls_strerror(ret)); - DEBUG(D_tls) debug_printf("read D-H parameters from file\n"); + { + fclose(fp); + return tls_error(US"malloc failed", strerror(errno), NULL); + } + sz = fread(m.data, m.size, 1, fp); + if (!sz) + { + saved_errno = errno; + fclose(fp); + free(m.data); + return tls_error(US"fread failed", strerror(saved_errno), NULL); + } + fclose(fp); + rc = gnutls_dh_params_import_pkcs3(dh_server_params, &m, GNUTLS_X509_FMT_PEM); free(m.data); + exim_gnutls_err_check(US"gnutls_dh_params_import_pkcs3"); + DEBUG(D_tls) debug_printf("read D-H parameters from file \"%s\"\n", filename); } /* If the file does not exist, fall through to compute new data and cache it. @@ -376,13 +455,13 @@ If there was any other opening error, it is serious. */ else if (errno == ENOENT) { - ret = -1; + rc = -1; DEBUG(D_tls) - debug_printf("parameter cache file %s does not exist\n", filename); + debug_printf("D-H parameter cache file \"%s\" does not exist\n", filename); } else - return tls_error(string_open_failed(errno, "%s for reading", filename), - host, NULL); + return tls_error(string_open_failed(errno, "\"%s\" for reading", filename), + NULL, NULL); /* If ret < 0, either the cache file does not exist, or the data it contains is not useful. One particular case of this is when upgrading from an older @@ -390,59 +469,72 @@ release of Exim in which the data was stored in a different format. We don't try to be clever and support both formats; we just regenerate new data in this case. */ -if (ret < 0) +if (rc < 0) { - uschar tempfilename[sizeof(filename) + 10]; + uschar *temp_fn; - DEBUG(D_tls) debug_printf("generating %d bit Diffie-Hellman key...\n", - DH_BITS); - ret = gnutls_dh_params_generate2(dh_params, DH_BITS); - if (ret < 0) return tls_error(US"D-H key generation", host, gnutls_strerror(ret)); + if ((PATH_MAX - Ustrlen(filename)) < 10) + return tls_error(US"Filename too long to generate replacement", + CS filename, NULL); - /* Write the parameters to a file in the spool directory so that we - can use them from other Exim processes. */ - - sprintf(CS tempfilename, "%s-%d", filename, (int)getpid()); - fd = Uopen(tempfilename, O_WRONLY|O_CREAT, 0400); + temp_fn = string_copy(US "%s.XXXXXXX"); + fd = mkstemp(CS temp_fn); /* modifies temp_fn */ if (fd < 0) - return tls_error(string_open_failed(errno, "%s for writing", filename), - host, NULL); + return tls_error(US"Unable to open temp file", strerror(errno), NULL); (void)fchown(fd, exim_uid, exim_gid); /* Probably not necessary */ - /* export the parameters in a format that can be generated using GNUTLS' - * certtool or other programs. - * - * The commands for certtool are: - * $ certtool --generate-dh-params --bits 1024 > params - */ - - m.size = PARAM_SIZE; + DEBUG(D_tls) debug_printf("generating %d bits Diffie-Hellman key ...\n", dh_bits); + rc = gnutls_dh_params_generate2(dh_server_params, dh_bits); + exim_gnutls_err_check(US"gnutls_dh_params_generate2"); + + /* gnutls_dh_params_export_pkcs3() will tell us the exact size, every time, + and I confirmed that a NULL call to get the size first is how the GnuTLS + sample apps handle this. */ + + sz = 0; + m.data = NULL; + rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, + m.data, &sz); + if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) + exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3(NULL) sizing"); + m.size = sz; m.data = malloc(m.size); if (m.data == NULL) - return tls_error(US"memory allocation failed", host, strerror(errno)); - - m.size = PARAM_SIZE; - ret = gnutls_dh_params_export_pkcs3(dh_params, GNUTLS_X509_FMT_PEM, m.data, - &m.size); - if (ret < 0) - return tls_error(US"DH params export", host, gnutls_strerror(ret)); - - m.size = Ustrlen(m.data); - errno = 0; - if (write(fd, m.data, m.size) != m.size || write(fd, "\n", 1) != 1) - return tls_error(US"TLS cache write failed", host, strerror(errno)); + return tls_error(US"memory allocation failed", strerror(errno), NULL); + rc = gnutls_dh_params_export_pkcs3(dh_server_params, GNUTLS_X509_FMT_PEM, + m.data, &sz); + if (rc != GNUTLS_E_SUCCESS) + { + free(m.data); + exim_gnutls_err_check(US"gnutls_dh_params_export_pkcs3() real"); + } + sz = write_to_fd_buf(fd, m.data, (size_t) m.size); + if (sz != m.size) + { + free(m.data); + return tls_error(US"TLS cache write D-H params failed", + strerror(errno), NULL); + } free(m.data); - (void)close(fd); + sz = write_to_fd_buf(fd, US"\n", 1); + if (sz != 1) + return tls_error(US"TLS cache write D-H params final newline failed", + strerror(errno), NULL); + + rc = close(fd); + if (rc) + return tls_error(US"TLS cache write close() failed", + strerror(errno), NULL); - if (rename(CS tempfilename, CS filename) < 0) - return tls_error(string_sprintf("failed to rename %s as %s", - tempfilename, filename), host, strerror(errno)); + if (Urename(temp_fn, filename) < 0) + return tls_error(string_sprintf("failed to rename \"%s\" as \"%s\"", + temp_fn, filename), strerror(errno), NULL); - DEBUG(D_tls) debug_printf("wrote D-H parameters to file %s\n", filename); + DEBUG(D_tls) debug_printf("wrote D-H parameters to file \"%s\"\n", filename); } -DEBUG(D_tls) debug_printf("initialized D-H parameters\n"); +DEBUG(D_tls) debug_printf("initialized server D-H parameters\n"); return OK; } @@ -450,90 +542,116 @@ return OK; /************************************************* -* Initialize for GnuTLS * +* Variables re-expanded post-SNI * *************************************************/ -/* Called from both server and client code. In the case of a server, errors -before actual TLS negotiation return DEFER. +/* Called from both server and client code, via tls_init(), and also from +the SNI callback after receiving an SNI, if tls_certificate includes "tls_sni". + +We can tell the two apart by state->received_sni being non-NULL in callback. + +The callback should not call us unless state->trigger_sni_changes is true, +which we are responsible for setting on the first pass through. Arguments: - host connected host, if client; NULL if server - certificate certificate file - privatekey private key file - cas CA certs file - crl CRL file + state exim_gnutls_state_st * Returns: OK/DEFER/FAIL */ static int -tls_init(host_item *host, uschar *certificate, uschar *privatekey, uschar *cas, - uschar *crl) +tls_expand_session_files(exim_gnutls_state_st *state) { int rc; -uschar *cert_expanded, *key_expanded, *cas_expanded, *crl_expanded; - -client_host = host; +const host_item *host = state->host; /* macro should be reconsidered? */ +uschar *saved_tls_certificate = NULL; +uschar *saved_tls_privatekey = NULL; +uschar *saved_tls_verify_certificates = NULL; +uschar *saved_tls_crl = NULL; +int cert_count; + +/* We check for tls_sni *before* expansion. */ +if (!state->host) + { + if (!state->received_sni) + { + if (Ustrstr(state->tls_certificate, US"tls_sni")) + { + DEBUG(D_tls) debug_printf("We will re-expand TLS session files if we receive SNI.\n"); + state->trigger_sni_changes = TRUE; + } + } + else + { + saved_tls_certificate = state->exp_tls_certificate; + saved_tls_privatekey = state->exp_tls_privatekey; + saved_tls_verify_certificates = state->exp_tls_verify_certificates; + saved_tls_crl = state->exp_tls_crl; + } + } -rc = gnutls_global_init(); -if (rc < 0) return tls_error(US"tls-init", host, gnutls_strerror(rc)); +/* remember: expand_check_tlsvar() is expand_check() but fiddling with +state members, assuming consistent naming; and expand_check() returns +false if expansion failed, unless expansion was forced to fail. */ -/* Create D-H parameters, or read them from the cache file. This function does -its own SMTP error messaging. */ +/* check if we at least have a certificate, before doing expensive +D-H generation. */ -rc = init_dh(host); -if (rc != OK) return rc; +if (!expand_check_tlsvar(tls_certificate)) + return DEFER; -/* Create the credentials structure */ +/* certificate is mandatory in server, optional in client */ -rc = gnutls_certificate_allocate_credentials(&x509_cred); -if (rc < 0) - return tls_error(US"certificate_allocate_credentials", - host, gnutls_strerror(rc)); - -/* This stuff must be done for each session, because different certificates -may be required for different sessions. */ +if ((state->exp_tls_certificate == NULL) || + (*state->exp_tls_certificate == '\0')) + { + if (state->host == NULL) + return tls_error(US"no TLS server certificate is specified", NULL, NULL); + else + DEBUG(D_tls) debug_printf("TLS: no client certificate specified; okay\n"); + } -if (!expand_check(certificate, US"tls_certificate", &cert_expanded)) +if (state->tls_privatekey && !expand_check_tlsvar(tls_privatekey)) return DEFER; -key_expanded = NULL; -if (privatekey != NULL) +/* tls_privatekey is optional, defaulting to same file as certificate */ + +if (state->tls_privatekey == NULL || *state->tls_privatekey == '\0') { - if (!expand_check(privatekey, US"tls_privatekey", &key_expanded)) - return DEFER; + state->tls_privatekey = state->tls_certificate; + state->exp_tls_privatekey = state->exp_tls_certificate; } -/* If expansion was forced to fail, key_expanded will be NULL. If the result of -the expansion is an empty string, ignore it also, and assume that the private -key is in the same file as the certificate. */ - -if (key_expanded == NULL || *key_expanded == 0) - key_expanded = cert_expanded; -/* Set the certificate and private keys */ - -if (cert_expanded != NULL) +if (state->exp_tls_certificate && *state->exp_tls_certificate) { + BOOL setit = TRUE; DEBUG(D_tls) debug_printf("certificate file = %s\nkey file = %s\n", - cert_expanded, key_expanded); - rc = gnutls_certificate_set_x509_key_file(x509_cred, CS cert_expanded, - CS key_expanded, GNUTLS_X509_FMT_PEM); - if (rc < 0) + state->exp_tls_certificate, state->exp_tls_privatekey); + + if (state->received_sni) { - uschar *msg = string_sprintf("cert/key setup: cert=%s key=%s", - cert_expanded, key_expanded); - return tls_error(msg, host, gnutls_strerror(rc)); + if ((Ustrcmp(state->exp_tls_certificate, saved_tls_certificate) == 0) && + (Ustrcmp(state->exp_tls_privatekey, saved_tls_privatekey) == 0)) + { + DEBUG(D_tls) debug_printf("cert and key unchanged with SNI.\n"); + setit = FALSE; + } + else + { + DEBUG(D_tls) debug_printf("SNI changed cert/key pair.\n"); + } } - } -/* A certificate is mandatory in a server, but not in a client */ - -else - { - if (host == NULL) - return tls_error(US"no TLS server certificate is specified", NULL, NULL); - DEBUG(D_tls) debug_printf("no TLS client certificate is specified\n"); + if (setit) + { + rc = gnutls_certificate_set_x509_key_file(state->x509_cred, + CS state->exp_tls_certificate, CS state->exp_tls_privatekey, + GNUTLS_X509_FMT_PEM); + exim_gnutls_err_check( + string_sprintf("cert/key setup: cert=%s key=%s", + state->exp_tls_certificate, state->exp_tls_privatekey)); + } } /* Set the trusted CAs file if one is provided, and then add the CRL if one is @@ -542,359 +660,516 @@ error message is provided. However, if we just refrain from setting anything up in that case, certificate verification fails, which seems to be the correct behaviour. */ -if (cas != NULL) +if (state->tls_verify_certificates && *state->tls_verify_certificates) { struct stat statbuf; + BOOL setit_vc = TRUE, setit_crl = TRUE; - if (!expand_check(cas, US"tls_verify_certificates", &cas_expanded)) + if (!expand_check_tlsvar(tls_verify_certificates)) return DEFER; + if (state->tls_crl && *state->tls_crl) + if (!expand_check_tlsvar(tls_crl)) + return DEFER; - if (stat(CS cas_expanded, &statbuf) < 0) + if (state->received_sni) + { + if (Ustrcmp(state->exp_tls_verify_certificates, saved_tls_verify_certificates) == 0) + setit_vc = FALSE; + if (Ustrcmp(state->exp_tls_crl, saved_tls_crl) == 0) + setit_crl = FALSE; + } + + /* nb: early exit; change if add more expansions to this function */ + if (!(setit_vc || setit_crl)) + return OK; + + if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) { log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " - "(tls_verify_certificates): %s", cas_expanded, strerror(errno)); + "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, + strerror(errno)); + return DEFER; + } + + if (!S_ISREG(statbuf.st_mode)) + { + DEBUG(D_tls) + debug_printf("verify certificates path is not a file: \"%s\"\n%s\n", + state->exp_tls_verify_certificates, + S_ISDIR(statbuf.st_mode) + ? " it's a directory, that's OpenSSL, this is GnuTLS" + : " (not a directory either)"); + log_write(0, LOG_MAIN|LOG_PANIC, + "tls_verify_certificates \"%s\" is not a file", + state->exp_tls_verify_certificates); return DEFER; } DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", - cas_expanded, statbuf.st_size); + state->exp_tls_verify_certificates, statbuf.st_size); - /* If the cert file is empty, there's no point in loading the CRL file. */ + /* If the CA cert file is empty, there's no point in loading the CRL file, + as we aren't verifying, so checking for revocation is pointless. */ if (statbuf.st_size > 0) { - rc = gnutls_certificate_set_x509_trust_file(x509_cred, CS cas_expanded, - GNUTLS_X509_FMT_PEM); - if (rc < 0) return tls_error(US"setup_certs", host, gnutls_strerror(rc)); - - if (crl != NULL && *crl != 0) + if (setit_vc) { - if (!expand_check(crl, US"tls_crl", &crl_expanded)) - return DEFER; - DEBUG(D_tls) debug_printf("loading CRL file = %s\n", crl_expanded); - rc = gnutls_certificate_set_x509_crl_file(x509_cred, CS crl_expanded, - GNUTLS_X509_FMT_PEM); - if (rc < 0) return tls_error(US"CRL setup", host, gnutls_strerror(rc)); + cert_count = gnutls_certificate_set_x509_trust_file(state->x509_cred, + CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); + if (cert_count < 0) + { + rc = cert_count; + exim_gnutls_err_check(US"gnutls_certificate_set_x509_trust_file"); + } + DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); } - } - } -/* Associate the parameters with the x509 credentials structure. */ - -gnutls_certificate_set_dh_params(x509_cred, dh_params); + if (setit_crl && state->tls_crl && *state->tls_crl) + { + if (state->exp_tls_crl && *state->exp_tls_crl) + { + DEBUG(D_tls) debug_printf("loading CRL file = %s\n", state->exp_tls_crl); + rc = gnutls_certificate_set_x509_crl_file(state->x509_cred, + CS state->exp_tls_crl, GNUTLS_X509_FMT_PEM); + exim_gnutls_err_check(US"gnutls_certificate_set_x509_crl_file"); + } + } + } /* statbuf.st_size */ + } /* tls_verify_certificates */ -DEBUG(D_tls) debug_printf("initialized certificate stuff\n"); return OK; +/* also above, during verify_certificates/crl, during SNI, if unchanged */ } /************************************************* -* Remove from a priority list * +* Initialize for GnuTLS * *************************************************/ -/* Cautiously written so that it will remove duplicates if present. +/* Called from both server and client code. In the case of a server, errors +before actual TLS negotiation return DEFER. Arguments: - list a zero-terminated list - remove_list a zero-terminated list to be removed + host connected host, if client; NULL if server + certificate certificate file + privatekey private key file + sni TLS SNI to send, sometimes when client; else NULL + cas CA certs file + crl CRL file + require_ciphers tls_require_ciphers setting -Returns: nothing +Returns: OK/DEFER/FAIL */ -static void -remove_priority(int *list, int *remove_list) +static int +tls_init( + const host_item *host, + const uschar *certificate, + const uschar *privatekey, + const uschar *sni, + const uschar *cas, + const uschar *crl, + const uschar *require_ciphers, + exim_gnutls_state_st **caller_state) { -for (; *remove_list != 0; remove_list++) +exim_gnutls_state_st *state; +int rc; +size_t sz; +const char *errpos; +uschar *p; +BOOL want_default_priorities; + +if (!exim_gnutls_base_init_done) { - int *p = list; - while (*p != 0) + DEBUG(D_tls) debug_printf("GnuTLS global init required.\n"); + + rc = gnutls_global_init(); + exim_gnutls_err_check(US"gnutls_global_init"); + +#if EXIM_GNUTLS_LIBRARY_LOG_LEVEL >= 0 + DEBUG(D_tls) { - if (*p == *remove_list) - { - int *pp = p; - do { pp[0] = pp[1]; pp++; } while (*pp != 0); - } - else p++; + gnutls_global_set_log_function(exim_gnutls_logger_cb); + /* arbitrarily chosen level; bump upto 9 for more */ + gnutls_global_set_log_level(EXIM_GNUTLS_LIBRARY_LOG_LEVEL); } +#endif + + exim_gnutls_base_init_done = TRUE; } -} +if (host) + { + state = &state_client; + memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); + DEBUG(D_tls) debug_printf("initialising GnuTLS client session\n"); + rc = gnutls_init(&state->session, GNUTLS_CLIENT); + } +else + { + state = &state_server; + memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); + DEBUG(D_tls) debug_printf("initialising GnuTLS server session\n"); + rc = gnutls_init(&state->session, GNUTLS_SERVER); + } +exim_gnutls_err_check(US"gnutls_init"); +state->host = host; -/************************************************* -* Add to a priority list * -*************************************************/ +state->tls_certificate = certificate; +state->tls_privatekey = privatekey; +state->tls_sni = sni; +state->tls_verify_certificates = cas; +state->tls_crl = crl; -/* Cautiously written to check the list size +rc = gnutls_certificate_allocate_credentials(&state->x509_cred); +exim_gnutls_err_check(US"gnutls_certificate_allocate_credentials"); -Arguments: - list a zero-terminated list - list_max maximum offset in the list - add_list a zero-terminated list to be added +/* This handles the variables that might get re-expanded after TLS SNI; +that's tls_certificate, tls_privatekey, tls_verify_certificates, tls_crl */ -Returns: TRUE if OK; FALSE if list overflows -*/ +DEBUG(D_tls) + debug_printf("Expanding various TLS configuration options for session credentials.\n"); +rc = tls_expand_session_files(state); +if (rc != OK) return rc; -static BOOL -add_priority(int *list, int list_max, int *add_list) -{ -int next = 0; -while (list[next] != 0) next++; -while (*add_list != 0) +/* Create D-H parameters, or read them from the cache file. This function does +its own SMTP error messaging. This only happens for the server, TLS D-H ignores +client-side params. */ + +if (!host) { - if (next >= list_max) return FALSE; - list[next++] = *add_list++; + rc = init_server_dh(); + if (rc != OK) return rc; + gnutls_certificate_set_dh_params(state->x509_cred, dh_server_params); } -list[next] = 0; -return TRUE; -} - - - -/************************************************* -* Adjust a priority list * -*************************************************/ - -/* This function is called to adjust the lists of cipher algorithms, MAC -algorithms, key-exchange methods, and protocols. -Arguments: - plist the appropriate priority list - psize the length of the list - s the configuation string - index the index of recognized strings - isize the length of the index +/* Link the credentials to the session. */ +rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); +exim_gnutls_err_check(US"gnutls_credentials_set"); - which text for an error message +/* set SNI in client, only */ +if (host) + { + if (!expand_check_tlsvar(tls_sni)) + return DEFER; + if (state->exp_tls_sni && *state->exp_tls_sni) + { + DEBUG(D_tls) + debug_printf("Setting TLS client SNI to \"%s\"\n", state->exp_tls_sni); + sz = Ustrlen(state->exp_tls_sni); + rc = gnutls_server_name_set(state->session, + GNUTLS_NAME_DNS, state->exp_tls_sni, sz); + exim_gnutls_err_check(US"gnutls_server_name_set"); + } + } +else if (state->tls_sni) + DEBUG(D_tls) debug_printf("*** PROBABLY A BUG *** " \ + "have an SNI set for a client [%s]\n", state->tls_sni); -Returns: FALSE if the table overflows, else TRUE -*/ +/* This is the priority string support, +http://www.gnu.org/software/gnutls/manual/html_node/Priority-Strings.html +and replaces gnutls_require_kx, gnutls_require_mac & gnutls_require_protocols. +This was backwards incompatible, but means Exim no longer needs to track +all algorithms and provide string forms for them. */ -static BOOL -set_priority(int *plist, int psize, uschar *s, pri_item *index, int isize, - uschar *which) -{ -int sep = 0; -BOOL first = TRUE; -uschar *t; +want_default_priorities = TRUE; -while ((t = string_nextinlist(&s, &sep, big_buffer, big_buffer_size)) != NULL) +if (state->tls_require_ciphers && *state->tls_require_ciphers) { - int i; - BOOL exclude = t[0] == '!'; - if (first && !exclude) plist[0] = 0; - first = FALSE; - for (i = 0; i < isize; i++) + if (!expand_check_tlsvar(tls_require_ciphers)) + return DEFER; + if (state->exp_tls_require_ciphers && *state->exp_tls_require_ciphers) { - uschar *ss = strstric(t, index[i].name, FALSE); - if (ss != NULL) - { - uschar *endss = ss + Ustrlen(index[i].name); - if ((ss == t || !isalnum(ss[-1])) && !isalnum(*endss)) - { - if (exclude) - remove_priority(plist, index[i].values); - else - { - if (!add_priority(plist, psize, index[i].values)) - { - log_write(0, LOG_MAIN|LOG_PANIC, "GnuTLS init failed: %s " - "priority table overflow", which); - return FALSE; - } - } - } - } + DEBUG(D_tls) debug_printf("GnuTLS session cipher/priority \"%s\"\n", + state->exp_tls_require_ciphers); + + rc = gnutls_priority_init(&state->priority_cache, + CS state->exp_tls_require_ciphers, &errpos); + want_default_priorities = FALSE; + p = state->exp_tls_require_ciphers; } } +if (want_default_priorities) + { + rc = gnutls_priority_init(&state->priority_cache, + exim_default_gnutls_priority, &errpos); + p = US exim_default_gnutls_priority; + } -DEBUG(D_tls) +exim_gnutls_err_check(string_sprintf( + "gnutls_priority_init(%s) failed at offset %ld, \"%.6s..\"", + p, errpos - CS p, errpos)); + +rc = gnutls_priority_set(state->session, state->priority_cache); +exim_gnutls_err_check(US"gnutls_priority_set"); + +gnutls_db_set_cache_expiration(state->session, ssl_session_timeout); + +/* Reduce security in favour of increased compatibility, if the admin +decides to make that trade-off. */ +if (gnutls_compat_mode) { - int *ptr = plist; - debug_printf("adjusted %s priorities:", which); - while (*ptr != 0) debug_printf(" %d", *ptr++); - debug_printf("\n"); +#if LIBGNUTLS_VERSION_NUMBER >= 0x020104 + DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n"); + gnutls_session_enable_compatibility_mode(state->session); +#else + DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n"); +#endif } -return TRUE; +*caller_state = state; +/* needs to happen before callbacks during handshake */ +current_global_tls_state = state; +return OK; } /************************************************* -* Initialize a single GNUTLS session * +* Extract peer information * *************************************************/ -/* Set the algorithm, the db backend, whether to request certificates etc. - -TLS in Exim was first implemented using OpenSSL. This has a function to which -you pass a list of cipher suites that are permitted/not permitted. GnuTLS works -differently. It operates using priority lists for the different components of -cipher suites. - -For compatibility of configuration, we scan a list of cipher suites and set -priorities therefrom. However, at the moment, we pay attention only to the bulk -cipher. +/* Called from both server and client code. +Only this is allowed to set state->peerdn and we use that to detect double-calls. Arguments: - side one of GNUTLS_SERVER, GNUTLS_CLIENT - expciphers expanded ciphers list or NULL - expmac expanded MAC list or NULL - expkx expanded key-exchange list or NULL - expproto expanded protocol list or NULL + state exim_gnutls_state_st * -Returns: a gnutls_session, or NULL if there is a problem +Returns: OK/DEFER/FAIL */ -static gnutls_session -tls_session_init(int side, uschar *expciphers, uschar *expmac, uschar *expkx, - uschar *expproto) +static int +peer_status(exim_gnutls_state_st *state) { -gnutls_session session; +const gnutls_datum *cert_list; +int rc; +unsigned int cert_list_size = 0; +gnutls_certificate_type_t ct; +gnutls_x509_crt_t crt; +uschar *dn_buf; +size_t sz; -gnutls_init(&session, side); +if (state->peerdn) + return OK; -/* Initialize the lists of permitted protocols, key-exchange methods, ciphers, -and MACs. */ +state->peerdn = US"unknown"; -memcpy(cipher_priority, default_cipher_priority, sizeof(cipher_priority)); -memcpy(mac_priority, default_mac_priority, sizeof(mac_priority)); -memcpy(kx_priority, default_kx_priority, sizeof(kx_priority)); -memcpy(proto_priority, default_proto_priority, sizeof(proto_priority)); +cert_list = gnutls_certificate_get_peers(state->session, &cert_list_size); -/* The names OpenSSL uses in tls_require_ciphers are of the form DES-CBC3-SHA, -using hyphen separators. GnuTLS uses underscore separators. So that I can use -either form for tls_require_ciphers in my tests, and also for general -convenience, we turn hyphens into underscores before scanning the list. */ +if (cert_list == NULL || cert_list_size == 0) + { + state->peerdn = US"unknown (no certificate)"; + DEBUG(D_tls) debug_printf("TLS: no certificate from peer (%p & %d)\n", + cert_list, cert_list_size); + if (state->verify_requirement == VERIFY_REQUIRED) + return tls_error(US"certificate verification failed", + "no certificate received from peer", state->host); + return OK; + } -if (expciphers != NULL) +ct = gnutls_certificate_type_get(state->session); +if (ct != GNUTLS_CRT_X509) { - uschar *s = expciphers; - while (*s != 0) { if (*s == '-') *s = '_'; s++; } + const char *ctn = gnutls_certificate_type_get_name(ct); + state->peerdn = string_sprintf("unknown (type %s)", ctn); + DEBUG(D_tls) + debug_printf("TLS: peer cert not X.509 but instead \"%s\"\n", ctn); + if (state->verify_requirement == VERIFY_REQUIRED) + return tls_error(US"certificate verification not possible, unhandled type", + ctn, state->host); + return OK; } -if ((expciphers != NULL && - !set_priority(cipher_priority, sizeof(cipher_priority)/sizeof(int), - expciphers, cipher_index, sizeof(cipher_index)/sizeof(pri_item), - US"cipher")) || - (expmac != NULL && - !set_priority(mac_priority, sizeof(mac_priority)/sizeof(int), - expmac, mac_index, sizeof(mac_index)/sizeof(pri_item), - US"MAC")) || - (expkx != NULL && - !set_priority(kx_priority, sizeof(kx_priority)/sizeof(int), - expkx, kx_index, sizeof(kx_index)/sizeof(pri_item), - US"key-exchange")) || - (expproto != NULL && - !set_priority(proto_priority, sizeof(proto_priority)/sizeof(int), - expproto, proto_index, sizeof(proto_index)/sizeof(pri_item), - US"protocol"))) +#define exim_gnutls_peer_err(Label) do { \ + if (rc != GNUTLS_E_SUCCESS) { \ + DEBUG(D_tls) debug_printf("TLS: peer cert problem: %s: %s\n", (Label), gnutls_strerror(rc)); \ + if (state->verify_requirement == VERIFY_REQUIRED) { return tls_error((Label), gnutls_strerror(rc), state->host); } \ + return OK; } } while (0) + +rc = gnutls_x509_crt_init(&crt); +exim_gnutls_peer_err(US"gnutls_x509_crt_init (crt)"); + +rc = gnutls_x509_crt_import(crt, &cert_list[0], GNUTLS_X509_FMT_DER); +exim_gnutls_peer_err(US"failed to import certificate [gnutls_x509_crt_import(cert 0)]"); +sz = 0; +rc = gnutls_x509_crt_get_dn(crt, NULL, &sz); +if (rc != GNUTLS_E_SHORT_MEMORY_BUFFER) { - gnutls_deinit(session); - return NULL; + exim_gnutls_peer_err(US"getting size for cert DN failed"); + return FAIL; /* should not happen */ } +dn_buf = store_get_perm(sz); +rc = gnutls_x509_crt_get_dn(crt, CS dn_buf, &sz); +exim_gnutls_peer_err(US"failed to extract certificate DN [gnutls_x509_crt_get_dn(cert 0)]"); +state->peerdn = dn_buf; + +return OK; +#undef exim_gnutls_peer_err +} -/* Define the various priorities */ -gnutls_cipher_set_priority(session, cipher_priority); -gnutls_compression_set_priority(session, comp_priority); -gnutls_kx_set_priority(session, kx_priority); -gnutls_protocol_set_priority(session, proto_priority); -gnutls_mac_set_priority(session, mac_priority); -gnutls_cred_set(session, GNUTLS_CRD_CERTIFICATE, x509_cred); -gnutls_dh_set_prime_bits(session, DH_BITS); +/************************************************* +* Verify peer certificate * +*************************************************/ -/* Request or demand a certificate of the peer, as configured. This will -happen only in a server. */ +/* Called from both server and client code. +*Should* be using a callback registered with +gnutls_certificate_set_verify_function() to fail the handshake if we dislike +the peer information, but that's too new for some OSes. -if (verify_requirement != VERIFY_NONE) - gnutls_certificate_server_set_request(session, - (verify_requirement == VERIFY_OPTIONAL)? - GNUTLS_CERT_REQUEST : GNUTLS_CERT_REQUIRE); +Arguments: + state exim_gnutls_state_st * + error where to put an error message -gnutls_db_set_cache_expiration(session, ssl_session_timeout); +Returns: + FALSE if the session should be rejected + TRUE if the cert is okay or we just don't care +*/ -/* Reduce security in favour of increased compatibility, if the admin -decides to make that trade-off. */ -if (gnutls_compat_mode) +static BOOL +verify_certificate(exim_gnutls_state_st *state, const char **error) +{ +int rc; +unsigned int verify; + +*error = NULL; + +rc = peer_status(state); +if (rc != OK) { -#if LIBGNUTLS_VERSION_NUMBER >= 0x020104 - DEBUG(D_tls) debug_printf("lowering GnuTLS security, compatibility mode\n"); - gnutls_session_enable_compatibility_mode(session); -#else - DEBUG(D_tls) debug_printf("Unable to set gnutls_compat_mode - GnuTLS version too old\n"); -#endif + verify = GNUTLS_CERT_INVALID; + *error = "not supplied"; + } +else + { + rc = gnutls_certificate_verify_peers2(state->session, &verify); } -DEBUG(D_tls) debug_printf("initialized GnuTLS session\n"); -return session; -} +/* Handle the result of verification. INVALID seems to be set as well +as REVOKED, but leave the test for both. */ +if ((rc < 0) || (verify & (GNUTLS_CERT_INVALID|GNUTLS_CERT_REVOKED)) != 0) + { + state->peer_cert_verified = FALSE; + if (*error == NULL) + *error = ((verify & GNUTLS_CERT_REVOKED) != 0) ? "revoked" : "invalid"; + DEBUG(D_tls) + debug_printf("TLS certificate verification failed (%s): peerdn=%s\n", + *error, state->peerdn); -/************************************************* -* Get name of cipher in use * -*************************************************/ + if (state->verify_requirement == VERIFY_REQUIRED) + { + gnutls_alert_send(state->session, GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE); + return FALSE; + } + DEBUG(D_tls) + debug_printf("TLS verify failure overriden (host in tls_try_verify_hosts)\n"); + } +else + { + state->peer_cert_verified = TRUE; + DEBUG(D_tls) debug_printf("TLS certificate verified: peerdn=%s\n", state->peerdn); + } -/* The answer is left in a static buffer, and tls_cipher is set to point -to it. +tls_peerdn = state->peerdn; -Argument: pointer to a GnuTLS session -Returns: nothing -*/ +return TRUE; +} + + + +/* ------------------------------------------------------------------------ */ +/* Callbacks */ + +/* Logging function which can be registered with + * gnutls_global_set_log_function() + * gnutls_global_set_log_level() 0..9 + */ static void -construct_cipher_name(gnutls_session session) +exim_gnutls_logger_cb(int level, const char *message) { -static uschar cipherbuf[256]; -uschar *ver; -int c, kx, mac; -#ifdef GNUTLS_CB_TLS_UNIQUE -int rc; -gnutls_datum_t channel; -#endif + DEBUG(D_tls) debug_printf("GnuTLS<%d>: %s\n", level, message); +} -ver = string_copy( - US gnutls_protocol_get_name(gnutls_protocol_get_version(session))); -if (Ustrncmp(ver, "TLS ", 4) == 0) ver[3] = '-'; /* Don't want space */ -c = gnutls_cipher_get(session); -/* returns size in "bytes" */ -tls_bits = gnutls_cipher_get_key_size(c) * 8; +/* Called after client hello, should handle SNI work. +This will always set tls_sni (state->received_sni) if available, +and may trigger presenting different certificates, +if state->trigger_sni_changes is TRUE. -mac = gnutls_mac_get(session); -kx = gnutls_kx_get(session); +Should be registered with + gnutls_handshake_set_post_client_hello_function() -string_format(cipherbuf, sizeof(cipherbuf), "%s:%s:%u", ver, - gnutls_cipher_suite_get_name(kx, c, mac), tls_bits); -tls_cipher = cipherbuf; +"This callback must return 0 on success or a gnutls error code to terminate the +handshake.". -DEBUG(D_tls) debug_printf("cipher: %s\n", cipherbuf); +For inability to get SNI information, we return 0. +We only return non-zero if re-setup failed. +*/ -if (tls_channelbinding_b64) - free(tls_channelbinding_b64); -tls_channelbinding_b64 = NULL; +static int +exim_sni_handling_cb(gnutls_session_t session) +{ +char sni_name[MAX_HOST_LEN]; +size_t data_len = MAX_HOST_LEN; +exim_gnutls_state_st *state = current_global_tls_state; +unsigned int sni_type; +int rc, old_pool; + +rc = gnutls_server_name_get(session, sni_name, &data_len, &sni_type, 0); +exim_gnutls_err_debugreturn0("gnutls_server_name_get()"); +if (sni_type != GNUTLS_NAME_DNS) + { + DEBUG(D_tls) debug_printf("TLS: ignoring SNI of unhandled type %u\n", sni_type); + return 0; + } -#ifdef GNUTLS_CB_TLS_UNIQUE -channel = { NULL, 0 }; -rc = gnutls_session_channel_binding(session, GNUTLS_CB_TLS_UNIQUE, &channel); -if (rc) { - DEBUG(D_tls) debug_printf("Channel binding error: %s\n", gnutls_strerror(rc)); -} else { - tls_channelbinding_b64 = auth_b64encode(channel.data, (int)channel.size); - DEBUG(D_tls) debug_printf("Have channel bindings cached for possible auth usage.\n"); -} -#endif +/* We now have a UTF-8 string in sni_name */ +old_pool = store_pool; +store_pool = POOL_PERM; +state->received_sni = string_copyn(US sni_name, data_len); +store_pool = old_pool; + +/* We set this one now so that variable expansions below will work */ +tls_sni = state->received_sni; + +DEBUG(D_tls) debug_printf("Received TLS SNI \"%s\"%s\n", sni_name, + state->trigger_sni_changes ? "" : " (unused for certificate selection)"); + +if (!state->trigger_sni_changes) + return 0; + +rc = tls_expand_session_files(state); +if (rc != OK) + { + /* If the setup of certs/etc failed before handshake, TLS would not have + been offered. The best we can do now is abort. */ + return GNUTLS_E_APPLICATION_ERROR_MIN; + } + +rc = gnutls_credentials_set(state->session, GNUTLS_CRD_CERTIFICATE, state->x509_cred); +return (rc == GNUTLS_E_SUCCESS) ? 0 : rc; } + +/* ------------------------------------------------------------------------ */ +/* Exported functions */ + + + + /************************************************* * Start a TLS session in a server * *************************************************/ @@ -905,9 +1180,6 @@ a TLS session. Arguments: require_ciphers list of allowed ciphers or NULL - require_mac list of allowed MACs or NULL - require_kx list of allowed key_exchange methods or NULL - require_proto list of allowed protocols or NULL Returns: OK on success DEFER for errors before the start of the negotiation @@ -916,21 +1188,18 @@ Returns: OK on success */ int -tls_server_start(uschar *require_ciphers, uschar *require_mac, - uschar *require_kx, uschar *require_proto) +tls_server_start(const uschar *require_ciphers) { int rc; const char *error; -uschar *expciphers = NULL; -uschar *expmac = NULL; -uschar *expkx = NULL; -uschar *expproto = NULL; +exim_gnutls_state_st *state = NULL; /* Check for previous activation */ +/* nb: this will not be TLS callout safe, needs reworking as part of that. */ if (tls_active >= 0) { - tls_error("STARTTLS received after TLS started", NULL, ""); + tls_error(US"STARTTLS received after TLS started", "", NULL); smtp_printf("554 Already in TLS\r\n"); return FAIL; } @@ -938,36 +1207,40 @@ if (tls_active >= 0) /* Initialize the library. If it fails, it will already have logged the error and sent an SMTP response. */ -DEBUG(D_tls) debug_printf("initializing GnuTLS as a server\n"); +DEBUG(D_tls) debug_printf("initialising GnuTLS as a server\n"); -rc = tls_init(NULL, tls_certificate, tls_privatekey, tls_verify_certificates, - tls_crl); +rc = tls_init(NULL, tls_certificate, tls_privatekey, + NULL, tls_verify_certificates, tls_crl, + require_ciphers, &state); if (rc != OK) return rc; -if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers) || - !expand_check(require_mac, US"gnutls_require_mac", &expmac) || - !expand_check(require_kx, US"gnutls_require_kx", &expkx) || - !expand_check(require_proto, US"gnutls_require_proto", &expproto)) - return FAIL; - /* If this is a host for which certificate verification is mandatory or optional, set up appropriately. */ -tls_certificate_verified = FALSE; -verify_requirement = VERIFY_NONE; - if (verify_check_host(&tls_verify_hosts) == OK) - verify_requirement = VERIFY_REQUIRED; + { + DEBUG(D_tls) debug_printf("TLS: a client certificate will be required.\n"); + state->verify_requirement = VERIFY_REQUIRED; + gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); + } else if (verify_check_host(&tls_try_verify_hosts) == OK) - verify_requirement = VERIFY_OPTIONAL; + { + DEBUG(D_tls) debug_printf("TLS: a client certificate will be requested but not required.\n"); + state->verify_requirement = VERIFY_OPTIONAL; + gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); + } +else + { + DEBUG(D_tls) debug_printf("TLS: a client certificate will not be requested.\n"); + state->verify_requirement = VERIFY_NONE; + gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_IGNORE); + } -/* Prepare for new connection */ +/* Register SNI handling; always, even if not in tls_certificate, so that the +expansion variable $tls_sni is always available. */ -tls_session = tls_session_init(GNUTLS_SERVER, expciphers, expmac, expkx, - expproto); -if (tls_session == NULL) - return tls_error(US"tls_session_init", NULL, - gnutls_strerror(GNUTLS_E_MEMORY_ERROR)); +gnutls_handshake_set_post_client_hello_function(state->session, + exim_sni_handling_cb); /* Set context and tell client to go ahead, except in the case of TLS startup on connection, where outputting anything now upsets the clients and tends to @@ -984,19 +1257,24 @@ if (!tls_on_connect) /* Now negotiate the TLS session. We put our own timer on it, since it seems that the GnuTLS library doesn't. */ -gnutls_transport_set_ptr2(tls_session, (gnutls_transport_ptr)fileno(smtp_in), - (gnutls_transport_ptr)fileno(smtp_out)); +gnutls_transport_set_ptr2(state->session, + (gnutls_transport_ptr)fileno(smtp_in), + (gnutls_transport_ptr)fileno(smtp_out)); +state->fd_in = fileno(smtp_in); +state->fd_out = fileno(smtp_out); sigalrm_seen = FALSE; if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); -rc = gnutls_handshake(tls_session); +do + { + rc = gnutls_handshake(state->session); + } while ((rc == GNUTLS_E_AGAIN) || (rc == GNUTLS_E_INTERRUPTED)); alarm(0); -if (rc < 0) +if (rc != GNUTLS_E_SUCCESS) { - tls_error(US"gnutls_handshake", NULL, - sigalrm_seen ? "timed out" : gnutls_strerror(rc)); - + tls_error(US"gnutls_handshake", + sigalrm_seen ? "timed out" : gnutls_strerror(rc), NULL); /* It seems that, except in the case of a timeout, we have to close the connection right here; otherwise if the other end is running OpenSSL it hangs until the server times out. */ @@ -1012,21 +1290,39 @@ if (rc < 0) DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); -if (verify_requirement != VERIFY_NONE && - !verify_certificate(tls_session, &error)) +/* Verify after the fact */ + +if (state->verify_requirement != VERIFY_NONE) { - tls_error(US"certificate verification failed", NULL, error); - return FAIL; + if (!verify_certificate(state, &error)) + { + if (state->verify_requirement == VERIFY_OPTIONAL) + { + DEBUG(D_tls) + debug_printf("TLS: continuing on only because verification was optional, after: %s\n", + error); + } + else + { + tls_error(US"certificate verification failed", error, NULL); + return FAIL; + } + } } -construct_cipher_name(tls_session); +/* Figure out peer DN, and if authenticated, etc. */ + +rc = peer_status(state); +if (rc != OK) return rc; + +/* Sets various Exim expansion variables; always safe within server */ + +extract_exim_vars_from_tls_state(state); /* TLS has been set up. Adjust the input functions to read via TLS, and initialize appropriately. */ -ssl_xfer_buffer = store_malloc(ssl_xfer_buffer_size); -ssl_xfer_buffer_lwm = ssl_xfer_buffer_hwm = 0; -ssl_xfer_eof = ssl_xfer_error = 0; +state->xfer_buffer = store_malloc(ssl_xfer_buffer_size); receive_getc = tls_getc; receive_ungetc = tls_ungetc; @@ -1034,8 +1330,6 @@ receive_feof = tls_feof; receive_ferror = tls_ferror; receive_smtp_buffered = tls_smtp_buffered; -tls_active = fileno(smtp_out); - return OK; } @@ -1052,16 +1346,13 @@ Arguments: fd the fd of the connection host connected host (for messages) addr the first address (not used) - dhparam DH parameter file + dhparam DH parameter file (ignored, we're a client) certificate certificate file privatekey private key file sni TLS SNI to send to remote host verify_certs file for certificate verify verify_crl CRL for verify require_ciphers list of allowed ciphers or NULL - require_mac list of allowed MACs or NULL - require_kx list of allowed key_exchange methods or NULL - require_proto list of allowed protocols or NULL timeout startup timeout Returns: OK/DEFER/FAIL (because using common functions), @@ -1069,114 +1360,116 @@ Returns: OK/DEFER/FAIL (because using common functions), */ int -tls_client_start(int fd, host_item *host, address_item *addr, uschar *dhparam, - uschar *certificate, uschar *privatekey, uschar *sni ARG_UNUSED, - uschar *verify_certs, uschar *verify_crl, - uschar *require_ciphers, uschar *require_mac, - uschar *require_kx, uschar *require_proto, int timeout) +tls_client_start(int fd, host_item *host, + address_item *addr ARG_UNUSED, uschar *dhparam ARG_UNUSED, + uschar *certificate, uschar *privatekey, uschar *sni, + uschar *verify_certs, uschar *verify_crl, + uschar *require_ciphers, int timeout) { -const gnutls_datum *server_certs; -uschar *expciphers = NULL; -uschar *expmac = NULL; -uschar *expkx = NULL; -uschar *expproto = NULL; -const char *error; -unsigned int server_certs_size; int rc; +const char *error; +exim_gnutls_state_st *state = NULL; -DEBUG(D_tls) debug_printf("initializing GnuTLS as a client\n"); +DEBUG(D_tls) debug_printf("initialising GnuTLS as a client on fd %d\n", fd); -verify_requirement = (verify_certs == NULL)? VERIFY_NONE : VERIFY_REQUIRED; -rc = tls_init(host, certificate, privatekey, verify_certs, verify_crl); +rc = tls_init(host, certificate, privatekey, + sni, verify_certs, verify_crl, require_ciphers, &state); if (rc != OK) return rc; -if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers) || - !expand_check(require_mac, US"gnutls_require_mac", &expmac) || - !expand_check(require_kx, US"gnutls_require_kx", &expkx) || - !expand_check(require_proto, US"gnutls_require_proto", &expproto)) - return FAIL; - -tls_session = tls_session_init(GNUTLS_CLIENT, expciphers, expmac, expkx, - expproto); +gnutls_dh_set_prime_bits(state->session, EXIM_CLIENT_DH_MIN_BITS); -if (tls_session == NULL) - return tls_error(US "tls_session_init", host, - gnutls_strerror(GNUTLS_E_MEMORY_ERROR)); +if (verify_certs == NULL) + { + DEBUG(D_tls) debug_printf("TLS: server certificate verification not required\n"); + state->verify_requirement = VERIFY_NONE; + /* we still ask for it, to log it, etc */ + gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUEST); + } +else + { + DEBUG(D_tls) debug_printf("TLS: server certificate verification required\n"); + state->verify_requirement = VERIFY_REQUIRED; + gnutls_certificate_server_set_request(state->session, GNUTLS_CERT_REQUIRE); + } -gnutls_transport_set_ptr(tls_session, (gnutls_transport_ptr)fd); +gnutls_transport_set_ptr(state->session, (gnutls_transport_ptr)fd); +state->fd_in = fd; +state->fd_out = fd; /* There doesn't seem to be a built-in timeout on connection. */ sigalrm_seen = FALSE; alarm(timeout); -rc = gnutls_handshake(tls_session); +do + { + rc = gnutls_handshake(state->session); + } while ((rc == GNUTLS_E_AGAIN) || (rc == GNUTLS_E_INTERRUPTED)); alarm(0); -if (rc < 0) - return tls_error(US "gnutls_handshake", host, - sigalrm_seen ? "timed out" : gnutls_strerror(rc)); +DEBUG(D_tls) debug_printf("gnutls_handshake was successful\n"); -server_certs = gnutls_certificate_get_peers(tls_session, &server_certs_size); +/* Verify late */ -if (server_certs != NULL) - { - uschar buff[1024]; - gnutls_x509_crt gcert; +if (state->verify_requirement != VERIFY_NONE && + !verify_certificate(state, &error)) + return tls_error(US"certificate verification failed", error, state->host); - gnutls_x509_crt_init(&gcert); - tls_peerdn = US"unknown"; +/* Figure out peer DN, and if authenticated, etc. */ - if (gnutls_x509_crt_import(gcert, server_certs, GNUTLS_X509_FMT_DER) == 0) - { - size_t bufsize = sizeof(buff); - if (gnutls_x509_crt_get_dn(gcert, CS buff, &bufsize) >= 0) - tls_peerdn = string_copy_malloc(buff); - } - } +rc = peer_status(state); +if (rc != OK) return rc; -/* Should we also verify the hostname here? */ +/* Sets various Exim expansion variables; always safe within server */ -if (verify_requirement != VERIFY_NONE && - !verify_certificate(tls_session, &error)) - return tls_error(US"certificate verification failed", host, error); +extract_exim_vars_from_tls_state(state); -construct_cipher_name(tls_session); /* Sets tls_cipher */ -tls_active = fd; return OK; } + /************************************************* -* Deal with logging errors during I/O * +* Close down a TLS session * *************************************************/ -/* We have to get the identity of the peer from saved data. - -Argument: - ec the GnuTLS error code, or 0 if it's a local error - when text identifying read or write - text local error text when ec is 0 +/* This is also called from within a delivery subprocess forked from the +daemon, to shut down the TLS library, without actually doing a shutdown (which +would tamper with the TLS session in the parent process). -Returns: nothing +Arguments: TRUE if gnutls_bye is to be called +Returns: nothing */ -static void -record_io_error(int ec, uschar *when, uschar *text) +void +tls_close(BOOL shutdown) { -const char *msg; +exim_gnutls_state_st *state = current_global_tls_state; -if (ec == GNUTLS_E_FATAL_ALERT_RECEIVED) - msg = string_sprintf("%s: %s", gnutls_strerror(ec), - gnutls_alert_get_name(gnutls_alert_get(tls_session))); -else - msg = gnutls_strerror(ec); +if (tls_active < 0) return; /* TLS was not active */ + +if (shutdown) + { + DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS\n"); + gnutls_bye(state->session, GNUTLS_SHUT_WR); + } + +gnutls_deinit(state->session); + +memcpy(state, &exim_gnutls_state_init, sizeof(exim_gnutls_state_init)); + +if ((state_server.session == NULL) && (state_client.session == NULL)) + { + gnutls_global_deinit(); + exim_gnutls_base_init_done = FALSE; + } -tls_error(when, client_host, msg); +tls_active = -1; } + /************************************************* * TLS version of getc * *************************************************/ @@ -1184,6 +1477,8 @@ tls_error(when, client_host, msg); /* This gets the next byte from the TLS input buffer. If the buffer is empty, it refills the buffer via the GnuTLS reading function. +This feeds DKIM and should be used for all message-body reads. + Arguments: none Returns: the next character or EOF */ @@ -1191,15 +1486,16 @@ Returns: the next character or EOF int tls_getc(void) { -if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) +exim_gnutls_state_st *state = current_global_tls_state; +if (state->xfer_buffer_lwm >= state->xfer_buffer_hwm) { - int inbytes; + ssize_t inbytes; - DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%lx, %lx, %u)\n", - (long) tls_session, (long) ssl_xfer_buffer, ssl_xfer_buffer_size); + DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%p, %p, %u)\n", + state->session, state->xfer_buffer, ssl_xfer_buffer_size); if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout); - inbytes = gnutls_record_recv(tls_session, CS ssl_xfer_buffer, + inbytes = gnutls_record_recv(state->session, state->xfer_buffer, ssl_xfer_buffer_size); alarm(0); @@ -1217,9 +1513,12 @@ if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) receive_ferror = smtp_ferror; receive_smtp_buffered = smtp_buffered; - gnutls_deinit(tls_session); - tls_session = NULL; + gnutls_deinit(state->session); + state->session = NULL; tls_active = -1; + tls_bits = 0; + tls_certificate_verified = FALSE; + tls_channelbinding_b64 = NULL; tls_cipher = NULL; tls_peerdn = NULL; @@ -1230,30 +1529,31 @@ if (ssl_xfer_buffer_lwm >= ssl_xfer_buffer_hwm) else if (inbytes < 0) { - record_io_error(inbytes, US"recv", NULL); - ssl_xfer_error = 1; + record_io_error(state, (int) inbytes, US"recv", NULL); + state->xfer_error = 1; return EOF; } #ifndef DISABLE_DKIM - dkim_exim_verify_feed(ssl_xfer_buffer, inbytes); + dkim_exim_verify_feed(state->xfer_buffer, inbytes); #endif - ssl_xfer_buffer_hwm = inbytes; - ssl_xfer_buffer_lwm = 0; + state->xfer_buffer_hwm = (int) inbytes; + state->xfer_buffer_lwm = 0; } - /* Something in the buffer; return next uschar */ -return ssl_xfer_buffer[ssl_xfer_buffer_lwm++]; +return state->xfer_buffer[state->xfer_buffer_lwm++]; } + /************************************************* * Read bytes from TLS channel * *************************************************/ -/* +/* This does not feed DKIM, so if the caller uses this for reading message body, +then the caller must feed DKIM. Arguments: buff buffer of data len size of buffer @@ -1265,24 +1565,36 @@ Returns: the number of bytes read int tls_read(uschar *buff, size_t len) { -int inbytes; +exim_gnutls_state_st *state = current_global_tls_state; +ssize_t inbytes; -DEBUG(D_tls) debug_printf("Calling gnutls_record_recv(%lx, %lx, %u)\n", - (long) tls_session, (long) buff, len); +if (len > INT_MAX) + len = INT_MAX; -inbytes = gnutls_record_recv(tls_session, CS buff, len); +if (state->xfer_buffer_lwm < state->xfer_buffer_hwm) + DEBUG(D_tls) + debug_printf("*** PROBABLY A BUG *** " \ + "tls_read() called with data in the tls_getc() buffer, %d ignored\n", + state->xfer_buffer_hwm - state->xfer_buffer_lwm); + +DEBUG(D_tls) + debug_printf("Calling gnutls_record_recv(%p, %p, " SIZE_T_FMT ")\n", + state->session, buff, len); + +inbytes = gnutls_record_recv(state->session, buff, len); if (inbytes > 0) return inbytes; if (inbytes == 0) { DEBUG(D_tls) debug_printf("Got TLS_EOF\n"); } -else record_io_error(inbytes, US"recv", NULL); +else record_io_error(state, (int)inbytes, US"recv", NULL); return -1; } + /************************************************* * Write bytes down TLS channel * *************************************************/ @@ -1299,25 +1611,26 @@ Returns: the number of bytes after a successful write, int tls_write(const uschar *buff, size_t len) { -int outbytes; -int left = len; +ssize_t outbytes; +size_t left = len; +exim_gnutls_state_st *state = current_global_tls_state; -DEBUG(D_tls) debug_printf("tls_do_write(%lx, %d)\n", (long) buff, left); +DEBUG(D_tls) debug_printf("tls_do_write(%p, " SIZE_T_FMT ")\n", buff, left); while (left > 0) { - DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %lx, %d)\n", (long)buff, - left); - outbytes = gnutls_record_send(tls_session, CS buff, left); + DEBUG(D_tls) debug_printf("gnutls_record_send(SSL, %p, " SIZE_T_FMT ")\n", + buff, left); + outbytes = gnutls_record_send(state->session, buff, left); - DEBUG(D_tls) debug_printf("outbytes=%d\n", outbytes); + DEBUG(D_tls) debug_printf("outbytes=" SSIZE_T_FMT "\n", outbytes); if (outbytes < 0) { - record_io_error(outbytes, US"send", NULL); + record_io_error(state, outbytes, US"send", NULL); return -1; } if (outbytes == 0) { - record_io_error(0, US"send", US"TLS channel closed on write"); + record_io_error(state, 0, US"send", US"TLS channel closed on write"); return -1; } @@ -1325,39 +1638,71 @@ while (left > 0) buff += outbytes; } -return len; +if (len > INT_MAX) + { + DEBUG(D_tls) + debug_printf("Whoops! Wrote more bytes (" SIZE_T_FMT ") than INT_MAX\n", + len); + len = INT_MAX; + } + +return (int) len; } + /************************************************* -* Close down a TLS session * +* Random number generation * *************************************************/ -/* This is also called from within a delivery subprocess forked from the -daemon, to shut down the TLS library, without actually doing a shutdown (which -would tamper with the TLS session in the parent process). +/* Pseudo-random number generation. The result is not expected to be +cryptographically strong but not so weak that someone will shoot themselves +in the foot using it as a nonce in input in some email header scheme or +whatever weirdness they'll twist this into. The result should handle fork() +and avoid repeating sequences. OpenSSL handles that for us. -Arguments: TRUE if gnutls_bye is to be called -Returns: nothing +Arguments: + max range maximum +Returns a random number in range [0, max-1] */ -void -tls_close(BOOL shutdown) +int +vaguely_random_number(int max) { -if (tls_active < 0) return; /* TLS was not active */ - -if (shutdown) +unsigned int r; +int i, needed_len; +uschar *p; +uschar smallbuf[sizeof(r)]; + +if (max <= 1) + return 0; + +needed_len = sizeof(r); +/* Don't take 8 times more entropy than needed if int is 8 octets and we were + * asked for a number less than 10. */ +for (r = max, i = 0; r; ++i) + r >>= 1; +i = (i + 7) / 8; +if (i < needed_len) + needed_len = i; + +i = gnutls_rnd(GNUTLS_RND_NONCE, smallbuf, needed_len); +if (i < 0) { - DEBUG(D_tls) debug_printf("tls_close(): shutting down TLS\n"); - gnutls_bye(tls_session, GNUTLS_SHUT_WR); + DEBUG(D_all) debug_printf("gnutls_rnd() failed, using fallback.\n"); + return vaguely_random_number_fallback(max); + } +r = 0; +for (p = smallbuf; needed_len; --needed_len, ++p) + { + r *= 256; + r += *p; } -gnutls_deinit(tls_session); -tls_session = NULL; -gnutls_global_deinit(); - -tls_active = -1; +/* We don't particularly care about weighted results; if someone wants + * smooth distribution and cares enough then they should submit a patch then. */ +return r % max; } diff --git a/src/src/tls-openssl.c b/src/src/tls-openssl.c index e609670ee..316fd5a90 100644 --- a/src/src/tls-openssl.c +++ b/src/src/tls-openssl.c @@ -779,11 +779,6 @@ a TLS session. Arguments: require_ciphers allowed ciphers - ------------------------------------------------------ - require_mac list of allowed MACs ) Not used - require_kx list of allowed key_exchange methods ) for - require_proto list of allowed protocols ) OpenSSL - ------------------------------------------------------ Returns: OK on success DEFER for errors before the start of the negotiation @@ -792,8 +787,7 @@ Returns: OK on success */ int -tls_server_start(uschar *require_ciphers, uschar *require_mac, - uschar *require_kx, uschar *require_proto) +tls_server_start(const uschar *require_ciphers) { int rc; uschar *expciphers; @@ -819,8 +813,9 @@ if (!expand_check(require_ciphers, US"tls_require_ciphers", &expciphers)) return FAIL; /* In OpenSSL, cipher components are separated by hyphens. In GnuTLS, they -are separated by underscores. So that I can use either form in my tests, and -also for general convenience, we turn underscores into hyphens here. */ +were historically separated by underscores. So that I can use either form in my +tests, and also for general convenience, we turn underscores into hyphens here. +*/ if (expciphers != NULL) { @@ -954,11 +949,6 @@ Argument: verify_certs file for certificate verify crl file containing CRL require_ciphers list of allowed ciphers - ------------------------------------------------------ - require_mac list of allowed MACs ) Not used - require_kx list of allowed key_exchange methods ) for - require_proto list of allowed protocols ) OpenSSL - ------------------------------------------------------ timeout startup timeout Returns: OK on success @@ -970,8 +960,7 @@ int tls_client_start(int fd, host_item *host, address_item *addr, uschar *dhparam, uschar *certificate, uschar *privatekey, uschar *sni, uschar *verify_certs, uschar *crl, - uschar *require_ciphers, uschar *require_mac, uschar *require_kx, - uschar *require_proto, int timeout) + uschar *require_ciphers, int timeout) { static uschar txt[256]; uschar *expciphers; @@ -1292,7 +1281,7 @@ fprintf(f, "Library version: OpenSSL: Compile: %s\n" /************************************************* -* Pseudo-random number generation * +* Random number generation * *************************************************/ /* Pseudo-random number generation. The result is not expected to be @@ -1307,7 +1296,7 @@ Returns a random number in range [0, max-1] */ int -pseudo_random_number(int max) +vaguely_random_number(int max) { unsigned int r; int i, needed_len; @@ -1343,7 +1332,14 @@ if (i < needed_len) needed_len = i; /* We do not care if crypto-strong */ -(void) RAND_pseudo_bytes(smallbuf, needed_len); +i = RAND_pseudo_bytes(smallbuf, needed_len); +if (i < 0) + { + DEBUG(D_all) + debug_printf("OpenSSL RAND_pseudo_bytes() not supported by RAND method, using fallback.\n"); + return vaguely_random_number_fallback(max); + } + r = 0; for (p = smallbuf; needed_len; --needed_len, ++p) { diff --git a/src/src/tls.c b/src/src/tls.c index d975a2c89..f0eba37f8 100644 --- a/src/src/tls.c +++ b/src/src/tls.c @@ -34,7 +34,7 @@ functions and the common functions below. */ static uschar *ssl_xfer_buffer = NULL; -static int ssl_xfer_buffer_size = 4096; +static const int ssl_xfer_buffer_size = 4096; static int ssl_xfer_buffer_lwm = 0; static int ssl_xfer_buffer_hwm = 0; static int ssl_xfer_eof = 0; @@ -59,11 +59,11 @@ Returns: TRUE if OK; result may still be NULL after forced failure */ static BOOL -expand_check(uschar *s, uschar *name, uschar **result) +expand_check(const uschar *s, const uschar *name, uschar **result) { if (s == NULL) *result = NULL; else { - *result = expand_string(s); + *result = expand_string(US s); /* need to clean up const some more */ if (*result == NULL && !expand_string_forcedfail) { log_write(0, LOG_MAIN|LOG_PANIC, "expansion of %s failed: %s", name, diff --git a/src/src/transports/smtp.c b/src/src/transports/smtp.c index 6ec94d5da..b01322662 100644 --- a/src/src/transports/smtp.c +++ b/src/src/transports/smtp.c @@ -62,6 +62,9 @@ optionlist smtp_transport_options[] = { { "gethostbyname", opt_bool, (void *)offsetof(smtp_transport_options_block, gethostbyname) }, #ifdef SUPPORT_TLS + /* These are no longer honoured, as of Exim 4.78; for now, we silently + ignore; a later release will warn, and a later-still release will remove + these options, so that using them becomes an error. */ { "gnutls_require_kx", opt_stringptr, (void *)offsetof(smtp_transport_options_block, gnutls_require_kx) }, { "gnutls_require_mac", opt_stringptr, @@ -1133,9 +1136,6 @@ if (tls_offered && !suppress_tls && ob->tls_verify_certificates, ob->tls_crl, ob->tls_require_ciphers, - ob->gnutls_require_mac, - ob->gnutls_require_kx, - ob->gnutls_require_proto, ob->command_timeout); /* TLS negotiation failed; give an error. From outside, this function may |