DKIM: fix selection of header for signing/verification given several. Bug 1792

4 files changed, 56 insertions, 59 deletions

diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index 12a28dd20..8df028e4e 100644
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -164,10 +164,13 @@ JH/38 Fix cutthrough bug with body lines having a single dot. The dot was
       received - but deduplicating mailstores were liable to retain only the
       initial truncated version.
 
-JH/39 Bug 1781: Fix use of private-keys having trailing '=' in the base-64.
+JH/39 Bug 1781: Fix use of DKIM private-keys having trailing '=' in the base-64.
 
 JH/40 Fix crash in queryprogram router when compiled with EXPERIMENTAL_SRS.
 
+JH/41 Bug 1792: Fix selection of headers to sign for DKIM: bottom-up.  While
+      we're in there, support oversigning also; bug 1309.
+
 
 
 Exim version 4.86
diff --git a/src/src/pdkim/pdkim.c b/src/src/pdkim/pdkim.c
index a951e6564..c5759b671 100644
--- a/src/src/pdkim/pdkim.c
+++ b/src/src/pdkim/pdkim.c
@@ -199,15 +199,8 @@ pdkim_stringlist *new_entry = malloc(sizeof(pdkim_stringlist));
 if (!new_entry) return NULL;
 memset(new_entry, 0, sizeof(pdkim_stringlist));
 if (!(new_entry->value = strdup(str))) return NULL;
-if (base)
-  {
-  pdkim_stringlist *last = base;
-  while (last->next != NULL) { last = last->next; }
-  last->next = new_entry;
-  return base;
-  }
-else
-  return new_entry;
+if (base) new_entry->next = base;
+return new_entry;
 }
 
 
@@ -1152,17 +1145,15 @@ if (ctx->mode == PDKIM_MODE_SIGN)
   pdkim_signature *sig;
 
   for (sig = ctx->sig; sig; sig = sig->next)			/* Traverse all signatures */
-    if (header_name_match(ctx->cur_header->str,
-			  sig->sign_headers) == PDKIM_OK)
-      {
-      pdkim_stringlist *list;
+    {
+    pdkim_stringlist *list;
 
-      /* Add header to the signed headers list (in reverse order) */
-      if (!(list = pdkim_prepend_stringlist(sig->headers,
-				    ctx->cur_header->str)))
-	return PDKIM_ERR_OOM;
-      sig->headers = list;
-      }
+    /* Add header to the signed headers list (in reverse order) */
+    if (!(list = pdkim_prepend_stringlist(sig->headers,
+				  ctx->cur_header->str)))
+      return PDKIM_ERR_OOM;
+    sig->headers = list;
+    }
   }
 
 /* VERIFICATION ----------------------------------------------------------- */
@@ -1594,35 +1585,36 @@ while (sig)
     int sep = 0;
 
     for (p = sig->headers; p; p = p->next)
-      {
-      uschar * rh;
-      /* Collect header names (Note: colon presence is guaranteed here) */
-      uschar * q = Ustrchr(p->value, ':');
+      if (header_name_match(p->value, sig->sign_headers) == PDKIM_OK)
+	{
+	uschar * rh;
+	/* Collect header names (Note: colon presence is guaranteed here) */
+	uschar * q = Ustrchr(p->value, ':');
 
-      if (!(pdkim_strncat(headernames, p->value,
-			(q - US p->value) + (p->next ? 1 : 0))))
-	return PDKIM_ERR_OOM;
+	if (!(pdkim_strncat(headernames, p->value,
+			  (q - US p->value) + (p->next ? 1 : 0))))
+	  return PDKIM_ERR_OOM;
 
-      rh = sig->canon_headers == PDKIM_CANON_RELAXED
-	? US pdkim_relax_header(p->value, 1) /* cook header for relaxed canon */
-	: string_copy(p->value);             /* just copy it for simple canon */
-      if (!rh)
-	return PDKIM_ERR_OOM;
+	rh = sig->canon_headers == PDKIM_CANON_RELAXED
+	  ? US pdkim_relax_header(p->value, 1) /* cook header for relaxed canon */
+	  : string_copy(p->value);             /* just copy it for simple canon */
+	if (!rh)
+	  return PDKIM_ERR_OOM;
 
-      /* Feed header to the hash algorithm */
-      exim_sha_update(&hhash_ctx, rh, strlen(rh));
+	/* Feed header to the hash algorithm */
+	exim_sha_update(&hhash_ctx, rh, strlen(rh));
 
-      /* Remember headers block for signing (when the library cannot do incremental)  */
-      (void) exim_rsa_data_append(&hdata, &hdata_alloc, rh);
+	/* Remember headers block for signing (when the library cannot do incremental)  */
+	(void) exim_rsa_data_append(&hdata, &hdata_alloc, rh);
 
-      DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh));
-      }
+	DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh));
+	}
 
     l = US sig->sign_headers;
     while((s = string_nextinlist(&l, &sep, NULL, 0)))
       if (*s != '_')
-	{
-	if (headernames->len > 0)
+	{			/*SSS string_append_listele() */
+	if (headernames->len > 0 && headernames->str[headernames->len-1] != ':')
 	  if (!(pdkim_strncat(headernames, ":", 1)))
 	    return PDKIM_ERR_OOM;
 	if (!(pdkim_strncat(headernames, CS s, Ustrlen(s))))
@@ -1651,6 +1643,7 @@ while (sig)
       if ((q = Ustrchr(p, ':')))
 	*q = '\0';
 
+/*XXX walk the list of headers in same order as received. */
       for (hdrs = ctx->headers; hdrs; hdrs = hdrs->next)
 	if (  hdrs->tag == 0
 	   && strncasecmp(hdrs->value, CS p, Ustrlen(p)) == 0
diff --git a/test/log/4503 b/test/log/4503
index cd14c8693..53781b966 100644
--- a/test/log/4503
+++ b/test/log/4503
@@ -1,27 +1,27 @@
 1999-03-02 09:44:33 10HmaX-0005vi-00 <= CALLER@myhost.test.ex U=CALLER P=local S=sss
-1999-03-02 09:44:33 10HmaY-0005vi-00 <= CALLER@myhost.test.ex U=CALLER P=local S=sss
-1999-03-02 09:44:33 10HmaZ-0005vi-00 <= CALLER@myhost.test.ex U=CALLER P=local S=sss
-1999-03-02 09:44:33 10HmaX-0005vi-00 => a@test.ex R=client T=send_to_server H=ip4.ip4.ip4.ip4 [ip4.ip4.ip4.ip4] C="250 OK id=10HmbA-0005vi-00"
+1999-03-02 09:44:33 10HmaX-0005vi-00 => a@test.ex R=client T=send_to_server H=ip4.ip4.ip4.ip4 [ip4.ip4.ip4.ip4] C="250 OK id=10HmaY-0005vi-00"
 1999-03-02 09:44:33 10HmaX-0005vi-00 Completed
-1999-03-02 09:44:33 10HmaY-0005vi-00 => b@test.ex R=client T=send_to_server H=ip4.ip4.ip4.ip4 [ip4.ip4.ip4.ip4] C="250 OK id=10HmbB-0005vi-00"
-1999-03-02 09:44:33 10HmaY-0005vi-00 Completed
-1999-03-02 09:44:33 10HmaZ-0005vi-00 => c@test.ex R=client T=send_to_server H=ip4.ip4.ip4.ip4 [ip4.ip4.ip4.ip4] C="250 OK id=10HmbC-0005vi-00"
+1999-03-02 09:44:33 10HmaZ-0005vi-00 <= CALLER@myhost.test.ex U=CALLER P=local S=sss
+1999-03-02 09:44:33 10HmaZ-0005vi-00 => b@test.ex R=client T=send_to_server H=ip4.ip4.ip4.ip4 [ip4.ip4.ip4.ip4] C="250 OK id=10HmbA-0005vi-00"
 1999-03-02 09:44:33 10HmaZ-0005vi-00 Completed
+1999-03-02 09:44:33 10HmbB-0005vi-00 <= CALLER@myhost.test.ex U=CALLER P=local S=sss
+1999-03-02 09:44:33 10HmbB-0005vi-00 => c@test.ex R=client T=send_to_server H=ip4.ip4.ip4.ip4 [ip4.ip4.ip4.ip4] C="250 OK id=10HmbC-0005vi-00"
+1999-03-02 09:44:33 10HmbB-0005vi-00 Completed
 
 ******** SERVER ********
 1999-03-02 09:44:33 exim x.yz daemon started: pid=pppp, no queue runs, listening for SMTP on port 1225
+1999-03-02 09:44:33 10HmaY-0005vi-00 DKIM: d=test.ex s=sel c=relaxed/relaxed a=rsa-sha256 b=1024 [verification succeeded]
+1999-03-02 09:44:33 10HmaY-0005vi-00 signer: test.ex bits: 1024 h=From
+1999-03-02 09:44:33 10HmaY-0005vi-00 <= CALLER@myhost.test.ex H=the.local.host.name (myhost.test.ex) [ip4.ip4.ip4.ip4] P=esmtp S=sss id=E10HmaX-0005vi-00@myhost.test.ex
+1999-03-02 09:44:33 10HmaY-0005vi-00 => :blackhole: <a@test.ex> R=server_dump
+1999-03-02 09:44:33 10HmaY-0005vi-00 Completed
 1999-03-02 09:44:33 10HmbA-0005vi-00 DKIM: d=test.ex s=sel c=relaxed/relaxed a=rsa-sha256 b=1024 [verification succeeded]
-1999-03-02 09:44:33 10HmbA-0005vi-00 signer: test.ex bits: 1024 h=From
-1999-03-02 09:44:33 10HmbA-0005vi-00 <= CALLER@myhost.test.ex H=the.local.host.name (myhost.test.ex) [ip4.ip4.ip4.ip4] P=esmtp S=sss id=E10HmaX-0005vi-00@myhost.test.ex
-1999-03-02 09:44:33 10HmbA-0005vi-00 => :blackhole: <a@test.ex> R=server_dump
+1999-03-02 09:44:33 10HmbA-0005vi-00 signer: test.ex bits: 1024 h=From:From
+1999-03-02 09:44:33 10HmbA-0005vi-00 <= CALLER@myhost.test.ex H=the.local.host.name (myhost.test.ex) [ip4.ip4.ip4.ip4] P=esmtp S=sss id=E10HmaZ-0005vi-00@myhost.test.ex
+1999-03-02 09:44:33 10HmbA-0005vi-00 => :blackhole: <b@test.ex> R=server_dump
 1999-03-02 09:44:33 10HmbA-0005vi-00 Completed
-1999-03-02 09:44:33 10HmbB-0005vi-00 DKIM: d=test.ex s=sel c=relaxed/relaxed a=rsa-sha256 b=1024 [verification succeeded]
-1999-03-02 09:44:33 10HmbB-0005vi-00 signer: test.ex bits: 1024 h=From:From
-1999-03-02 09:44:33 10HmbB-0005vi-00 <= CALLER@myhost.test.ex H=the.local.host.name (myhost.test.ex) [ip4.ip4.ip4.ip4] P=esmtp S=sss id=E10HmaY-0005vi-00@myhost.test.ex
-1999-03-02 09:44:33 10HmbB-0005vi-00 => :blackhole: <b@test.ex> R=server_dump
-1999-03-02 09:44:33 10HmbB-0005vi-00 Completed
 1999-03-02 09:44:33 10HmbC-0005vi-00 DKIM: d=test.ex s=sel c=relaxed/relaxed a=rsa-sha256 b=1024 [verification succeeded]
-1999-03-02 09:44:33 10HmbC-0005vi-00 signer: test.ex bits: 1024 h=From:Message-Id:Sender:Date:Reply-To:Subject:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Id:List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive
-1999-03-02 09:44:33 10HmbC-0005vi-00 <= CALLER@myhost.test.ex H=the.local.host.name (myhost.test.ex) [ip4.ip4.ip4.ip4] P=esmtp S=sss id=E10HmaZ-0005vi-00@myhost.test.ex
+1999-03-02 09:44:33 10HmbC-0005vi-00 signer: test.ex bits: 1024 h=Date:Sender:Message-Id:From:Reply-To:Subject:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Id:List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive
+1999-03-02 09:44:33 10HmbC-0005vi-00 <= CALLER@myhost.test.ex H=the.local.host.name (myhost.test.ex) [ip4.ip4.ip4.ip4] P=esmtp S=sss id=E10HmbB-0005vi-00@myhost.test.ex
 1999-03-02 09:44:33 10HmbC-0005vi-00 => :blackhole: <c@test.ex> R=server_dump
 1999-03-02 09:44:33 10HmbC-0005vi-00 Completed
diff --git a/test/scripts/4500-Domain-Keys-Identified-Mail/4503 b/test/scripts/4500-Domain-Keys-Identified-Mail/4503
index 45be7c2c6..140e6d6bf 100644
--- a/test/scripts/4500-Domain-Keys-Identified-Mail/4503
+++ b/test/scripts/4500-Domain-Keys-Identified-Mail/4503
@@ -4,21 +4,22 @@ exim -bd -DSERVER=server -oX PORT_D
 ****
 #
 # single header signed
-exim -DOPT=From a@test.ex
+exim -DOPT=From -odf a@test.ex
 From: nobody@example.com
+From: second@example.com
 
 content
 ****
 #
 # single header, oversigned
-exim -DOPT=From:From b@test.ex
+exim -DOPT=From:From -odf b@test.ex
 From: nobody@example.com
 
 content
 ****
 #
 # default header set
-exim -DHEADERS_MAXSIZE=y c@test.ex
+exim -DHEADERS_MAXSIZE=y -odf c@test.ex
 From: nobody@example.com
 
 content