diff options
| -rw-r--r-- | doc/doc-docbook/spec.xfpt | 66 | ||||
| -rw-r--r-- | doc/doc-txt/ChangeLog | 4 | ||||
| -rw-r--r-- | src/src/tls-gnu.c | 86 | ||||
| -rw-r--r-- | src/src/tls-openssl.c | 91 |
4 files changed, 148 insertions, 99 deletions
diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index 5bdf57282..dc7e4f75c 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -16481,14 +16481,24 @@ See &%tls_verify_hosts%& below. .option tls_verify_certificates main string&!! unset .cindex "TLS" "client certificate verification" .cindex "certificate" "verification of client" -The value of this option is expanded, and must then be the absolute path to -a file containing permitted certificates for clients that -match &%tls_verify_hosts%& or &%tls_try_verify_hosts%&. Alternatively, if you -are using either GnuTLS version 3.3.6 (or later) or OpenSSL, -you can set &%tls_verify_certificates%& to the name of a -directory containing certificate files. -For earlier versions of GnuTLS -the option must be set to the name of a single file. +The value of this option is expanded, and must then be either the +word "system" +or the absolute path to +a file or directory containing permitted certificates for clients that +match &%tls_verify_hosts%& or &%tls_try_verify_hosts%&. + +The "system" value for the option will use a +system default location compiled into the SSL library. +This is not available for GnuTLS versions preceding 3.0.20 and an explicit location +must be specified. + +The use of a directory for the option value is not avilable for GnuTLS versions +preceding 3.3.6 and a single file must be used. + +With OpenSSL the certificates specified +explicitly +either by file or directory +are added to those given by the system default location. With OpenSSL the certificates specified explicitly @@ -23453,15 +23463,18 @@ There is no equivalent checking on client certificates. .cindex "certificate" "verification of server" .vindex "&$host$&" .vindex "&$host_address$&" -The value of this option must be the absolute path to a file containing -permitted server certificates, for use when setting up an encrypted connection. -Alternatively, -if you are using either GnuTLS version 3.3.6 (or later) or OpenSSL, -you can set -&%tls_verify_certificates%& to the name of a directory containing certificate -files. -For earlier versions of GnuTLS the option must be set to the name of a -single file. +The value of this option must be either the +word "system" +or the absolute path to +a file or directory containing permitted certificates for servers, +for use when setting up an encrypted connection. + +The "system" value for the option will use a location compiled into the SSL library. +This is not available for GnuTLS versions preceding 3.0.20 and an explicit location +must be specified. + +The use of a directory for the option value is not avilable for GnuTLS versions +preceding 3.3.6 and a single file must be used. With OpenSSL the certificates specified explicitly @@ -25949,8 +25962,9 @@ include files and libraries for GnuTLS can be found. There are some differences in usage when using GnuTLS instead of OpenSSL: .ilist -The &%tls_verify_certificates%& option must contain the name of a file, not the -name of a directory for GnuTLS versions before 3.3.6 +The &%tls_verify_certificates%& option +cannot be the path of a directory +for GnuTLS versions before 3.3.6 (for later versions, or OpenSSL, it can be either). .next The default value for &%tls_dhparam%& differs for historical reasons. @@ -26302,8 +26316,10 @@ session with a client, you must set either &%tls_verify_hosts%& or apply to all TLS connections. For any host that matches one of these options, Exim requests a certificate as part of the setup of the TLS session. The contents of the certificate are verified by comparing it with a list of -expected certificates. These must be available in a file or, -for OpenSSL only (not GnuTLS), a directory, identified by +expected certificates. +These may be the system default set (depending on library version), +an explicit file or, +depending on library version, a directory, identified by &%tls_verify_certificates%&. A file can contain multiple certificates, concatenated end to end. If a @@ -26463,9 +26479,13 @@ if it requests it. If the server is Exim, it will request a certificate only if &%tls_verify_hosts%& or &%tls_try_verify_hosts%& matches the client. If the &%tls_verify_certificates%& option is set on the &(smtp)& transport, it +specified a collection of expected server certificates. +These may be the system default set (depeding on library version), +a file or, +depnding on liibrary version, a directory, must name a file or, -for OpenSSL only (not GnuTLS), a directory, that contains a collection of -expected server certificates. The client verifies the server's certificate +for OpenSSL only (not GnuTLS), a directory. +The client verifies the server's certificate against this collection, taking into account any revoked certificates that are in the list defined by &%tls_crl%&. Failure to verify fails the TLS connection unless either of the diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog index 27abe4701..f2954b945 100644 --- a/doc/doc-txt/ChangeLog +++ b/doc/doc-txt/ChangeLog @@ -17,6 +17,10 @@ JH/04 Certificate name checking on server certificates, when exim is a client, can be used to disable this per-host. The build option EXPERIMENTAL_CERTNAMES is withdrawn. +JH/05 The value of the tls_verify_certificates smtp transport and main options + can now be the word "system" to access the system default CA bundle. + For GnuTLS, only version 3.0.20 or later. + Exim version 4.85 ----------------- diff --git a/src/src/tls-gnu.c b/src/src/tls-gnu.c index b520ebfd8..4943f48b7 100644 --- a/src/src/tls-gnu.c +++ b/src/src/tls-gnu.c @@ -56,6 +56,9 @@ require current GnuTLS, then we'll drop support for the ancient libraries). #else # undef SUPPORT_CA_DIR #endif +#if GNUTLS_VERSION_NUMBER >= 0x030314 +# define SUPPORT_SYSDEFAULT_CABUNDLE +#endif #ifndef DISABLE_OCSP # include <gnutls/ocsp.h> @@ -874,58 +877,65 @@ else return OK; } -if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) +#ifdef SUPPORT_SYSDEFAULT_CABUNDLE +if (Ustrcmp(state->exp_tls_verify_certificates, "system") == 0) + cert_count = gnutls_certificate_set_x509_system_trust(state->x509_cred); +else +#endif { - log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " - "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, - strerror(errno)); - return DEFER; - } + if (Ustat(state->exp_tls_verify_certificates, &statbuf) < 0) + { + log_write(0, LOG_MAIN|LOG_PANIC, "could not stat %s " + "(tls_verify_certificates): %s", state->exp_tls_verify_certificates, + strerror(errno)); + return DEFER; + } #ifndef SUPPORT_CA_DIR -/* The test suite passes in /dev/null; we could check for that path explicitly, -but who knows if someone has some weird FIFO which always dumps some certs, or -other weirdness. The thing we really want to check is that it's not a -directory, since while OpenSSL supports that, GnuTLS does not. -So s/!S_ISREG/S_ISDIR/ and change some messsaging ... */ -if (S_ISDIR(statbuf.st_mode)) - { - DEBUG(D_tls) - debug_printf("verify certificates path is a dir: \"%s\"\n", - state->exp_tls_verify_certificates); - log_write(0, LOG_MAIN|LOG_PANIC, - "tls_verify_certificates \"%s\" is a directory", - state->exp_tls_verify_certificates); - return DEFER; - } + /* The test suite passes in /dev/null; we could check for that path explicitly, + but who knows if someone has some weird FIFO which always dumps some certs, or + other weirdness. The thing we really want to check is that it's not a + directory, since while OpenSSL supports that, GnuTLS does not. + So s/!S_ISREG/S_ISDIR/ and change some messsaging ... */ + if (S_ISDIR(statbuf.st_mode)) + { + DEBUG(D_tls) + debug_printf("verify certificates path is a dir: \"%s\"\n", + state->exp_tls_verify_certificates); + log_write(0, LOG_MAIN|LOG_PANIC, + "tls_verify_certificates \"%s\" is a directory", + state->exp_tls_verify_certificates); + return DEFER; + } #endif -DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", - state->exp_tls_verify_certificates, statbuf.st_size); + DEBUG(D_tls) debug_printf("verify certificates = %s size=" OFF_T_FMT "\n", + state->exp_tls_verify_certificates, statbuf.st_size); -if (statbuf.st_size == 0) - { - DEBUG(D_tls) - debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); - return OK; - } + if (statbuf.st_size == 0) + { + DEBUG(D_tls) + debug_printf("cert file empty, no certs, no verification, ignoring any CRL\n"); + return OK; + } -cert_count = + cert_count = #ifdef SUPPORT_CA_DIR - (statbuf.st_mode & S_IFMT) == S_IFDIR - ? - gnutls_certificate_set_x509_trust_dir(state->x509_cred, - CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM) - : + (statbuf.st_mode & S_IFMT) == S_IFDIR + ? + gnutls_certificate_set_x509_trust_dir(state->x509_cred, + CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM) + : #endif - gnutls_certificate_set_x509_trust_file(state->x509_cred, - CS state->exp_tls_verify_certificates, GNUTLS_X509_FMT_PEM); + 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"); + exim_gnutls_err_check(US"setting certificate trust"); } DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", cert_count); diff --git a/src/src/tls-openssl.c b/src/src/tls-openssl.c index 7c66775c0..bb17821e4 100644 --- a/src/src/tls-openssl.c +++ b/src/src/tls-openssl.c @@ -1366,50 +1366,65 @@ if (!expand_check(certs, US"tls_verify_certificates", &expcerts)) if (expcerts != NULL && *expcerts != '\0') { - struct stat statbuf; - if (!SSL_CTX_set_default_verify_paths(sctx)) - return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL); - - if (Ustat(expcerts, &statbuf) < 0) + if (Ustrcmp(expcerts, "system") == 0) { - log_write(0, LOG_MAIN|LOG_PANIC, - "failed to stat %s for certificates", expcerts); - return DEFER; + /* Tell the library to use its compiled-in location for the system default + CA bundle, only */ + + if (!SSL_CTX_set_default_verify_paths(sctx)) + return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL); } else { - uschar *file, *dir; - if ((statbuf.st_mode & S_IFMT) == S_IFDIR) - { file = NULL; dir = expcerts; } + struct stat statbuf; + + /* Tell the library to use its compiled-in location for the system default + CA bundle. Those given by the exim config are additional to these */ + + if (!SSL_CTX_set_default_verify_paths(sctx)) + return tls_error(US"SSL_CTX_set_default_verify_paths", host, NULL); + + if (Ustat(expcerts, &statbuf) < 0) + { + log_write(0, LOG_MAIN|LOG_PANIC, + "failed to stat %s for certificates", expcerts); + return DEFER; + } else - { file = expcerts; dir = NULL; } - - /* If a certificate file is empty, the next function fails with an - unhelpful error message. If we skip it, we get the correct behaviour (no - certificates are recognized, but the error message is still misleading (it - says no certificate was supplied.) But this is better. */ - - if ((file == NULL || statbuf.st_size > 0) && - !SSL_CTX_load_verify_locations(sctx, CS file, CS dir)) - return tls_error(US"SSL_CTX_load_verify_locations", host, NULL); - - /* Load the list of CAs for which we will accept certs, for sending - to the client. This is only for the one-file tls_verify_certificates - variant. - If a list isn't loaded into the server, but - some verify locations are set, the server end appears to make - a wildcard reqest for client certs. - Meanwhile, the client library as deafult behaviour *ignores* the list - we send over the wire - see man SSL_CTX_set_client_cert_cb. - Because of this, and that the dir variant is likely only used for - the public-CA bundle (not for a private CA), not worth fixing. - */ - if (file != NULL) { - STACK_OF(X509_NAME) * names = SSL_load_client_CA_file(CS file); -DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", - sk_X509_NAME_num(names)); - SSL_CTX_set_client_CA_list(sctx, names); + uschar *file, *dir; + if ((statbuf.st_mode & S_IFMT) == S_IFDIR) + { file = NULL; dir = expcerts; } + else + { file = expcerts; dir = NULL; } + + /* If a certificate file is empty, the next function fails with an + unhelpful error message. If we skip it, we get the correct behaviour (no + certificates are recognized, but the error message is still misleading (it + says no certificate was supplied.) But this is better. */ + + if ((file == NULL || statbuf.st_size > 0) && + !SSL_CTX_load_verify_locations(sctx, CS file, CS dir)) + return tls_error(US"SSL_CTX_load_verify_locations", host, NULL); + + /* Load the list of CAs for which we will accept certs, for sending + to the client. This is only for the one-file tls_verify_certificates + variant. + If a list isn't loaded into the server, but + some verify locations are set, the server end appears to make + a wildcard reqest for client certs. + Meanwhile, the client library as deafult behaviour *ignores* the list + we send over the wire - see man SSL_CTX_set_client_cert_cb. + Because of this, and that the dir variant is likely only used for + the public-CA bundle (not for a private CA), not worth fixing. + */ + if (file != NULL) + { + STACK_OF(X509_NAME) * names = SSL_load_client_CA_file(CS file); + DEBUG(D_tls) debug_printf("Added %d certificate authorities.\n", + sk_X509_NAME_num(names)); + SSL_CTX_set_client_CA_list(sctx, names); + } } } |