X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/41468ba140a1678e7491534fa3cddded53e1e6d2..a5ffa9b475a426bc73366db01f7cc92a3811bc3a:/src/src/dkim.c

diff --git a/src/src/dkim.c b/src/src/dkim.c
index 2873eda53..b9dbce68d 100644
--- a/src/src/dkim.c
+++ b/src/src/dkim.c
@@ -18,7 +18,7 @@ int dkim_verify_oldpool;
 pdkim_ctx *dkim_verify_ctx = NULL;
 pdkim_signature *dkim_signatures = NULL;
 pdkim_signature *dkim_cur_sig = NULL;
-static BOOL dkim_collect_error = FALSE;
+static const uschar * dkim_collect_error = NULL;
 
 static int
 dkim_exim_query_dns_txt(char *name, char *answer)
@@ -88,7 +88,7 @@ if (dkim_verify_ctx)
 
 dkim_verify_ctx = pdkim_init_verify(&dkim_exim_query_dns_txt, dot_stuffing);
 dkim_collect_input = !!dkim_verify_ctx;
-dkim_collect_error = FALSE;
+dkim_collect_error = NULL;
 
 /* Start feed up with any cached data */
 receive_get_cache();
@@ -106,9 +106,9 @@ store_pool = POOL_PERM;
 if (  dkim_collect_input
    && (rc = pdkim_feed(dkim_verify_ctx, CS data, len)) != PDKIM_OK)
   {
+  dkim_collect_error = pdkim_errstr(rc);
   log_write(0, LOG_MAIN,
-	     "DKIM: validation error: %.100s", pdkim_errstr(rc));
-  dkim_collect_error = TRUE;
+	     "DKIM: validation error: %.100s", dkim_collect_error);
   dkim_collect_input = FALSE;
   }
 store_pool = dkim_verify_oldpool;
@@ -119,9 +119,8 @@ void
 dkim_exim_verify_finish(void)
 {
 pdkim_signature * sig = NULL;
-int dkim_signers_size = 0;
-int dkim_signers_ptr = 0;
-int rc;
+int dkim_signers_size = 0, dkim_signers_ptr = 0, rc;
+const uschar * errstr;
 
 store_pool = POOL_PERM;
 
@@ -133,8 +132,8 @@ dkim_signatures = NULL;
 if (dkim_collect_error)
   {
   log_write(0, LOG_MAIN,
-	     "DKIM: Error while running this message through validation,"
-	     " disabling signature verification.");
+      "DKIM: Error during validation, disabling signature verification: %.100s",
+      dkim_collect_error);
   dkim_disable_verify = TRUE;
   goto out;
   }
@@ -143,10 +142,11 @@ dkim_collect_input = FALSE;
 
 /* Finish DKIM operation and fetch link to signatures chain */
 
-if ((rc = pdkim_feed_finish(dkim_verify_ctx, &dkim_signatures)) != PDKIM_OK)
+rc = pdkim_feed_finish(dkim_verify_ctx, &dkim_signatures, &errstr);
+if (rc != PDKIM_OK)
   {
-  log_write(0, LOG_MAIN,
-	     "DKIM: validation error: %.100s", pdkim_errstr(rc));
+  log_write(0, LOG_MAIN, "DKIM: validation error: %.100s%s%s", pdkim_errstr(rc),
+	    errstr ? ": " : "", errstr ? errstr : US"");
   goto out;
   }
 
@@ -448,15 +448,19 @@ switch (what)
 }
 
 
+/* Generate signatures for the given file, returning a string.
+If a prefix is given, prepend it to the file for the calculations.
+*/
+
 uschar *
-dkim_exim_sign(int dkim_fd, struct ob_dkim * dkim)
+dkim_exim_sign(int fd, off_t off, uschar * prefix,
+  struct ob_dkim * dkim, const uschar ** errstr)
 {
 const uschar * dkim_domain;
 int sep = 0;
 uschar *seen_items = NULL;
 int seen_items_size = 0;
 int seen_items_offset = 0;
-uschar itembuf[256];
 uschar *dkim_canon_expanded;
 uschar *dkim_sign_headers_expanded;
 uschar *dkim_private_key_expanded;
@@ -485,10 +489,9 @@ if (!(dkim_domain = expand_cstring(dkim->dkim_domain)))
 
 /* Set $dkim_domain expansion variable to each unique domain in list. */
 
-while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep,
-				   itembuf, sizeof(itembuf))))
+while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, NULL, 0)))
   {
-  if (!dkim_signing_domain || dkim_signing_domain[0] == '\0')
+  if (dkim_signing_domain[0] == '\0')
     continue;
 
   /* Only sign once for each domain, no matter how often it
@@ -571,7 +574,7 @@ while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep,
 
   if (dkim_private_key_expanded[0] == '/')
     {
-    int privkey_fd = 0;
+    int privkey_fd, off = 0, len;
 
     /* Looks like a filename, load the private key. */
 
@@ -585,24 +588,33 @@ while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep,
       goto bad;
       }
 
-    if (read(privkey_fd, big_buffer, big_buffer_size - 2) < 0)
+    do
       {
-      log_write(0, LOG_MAIN|LOG_PANIC, "unable to read private key file: %s",
-		 dkim_private_key_expanded);
-      goto bad;
+      if ((len = read(privkey_fd, big_buffer + off, big_buffer_size - 2 - off)) < 0)
+	{
+	(void) close(privkey_fd);
+	log_write(0, LOG_MAIN|LOG_PANIC, "unable to read private key file: %s",
+		   dkim_private_key_expanded);
+	goto bad;
+	}
+      off += len;
       }
+    while (len > 0);
 
     (void) close(privkey_fd);
+    big_buffer[off] = '\0';
     dkim_private_key_expanded = big_buffer;
     }
 
-  ctx = pdkim_init_sign(CS dkim_signing_domain,
+  if (!(ctx = pdkim_init_sign(CS dkim_signing_domain,
 			CS dkim_signing_selector,
 			CS dkim_private_key_expanded,
 			PDKIM_ALGO_RSA_SHA256,
 			dkim->dot_stuffed,
-			&dkim_exim_query_dns_txt
-			);
+			&dkim_exim_query_dns_txt,
+			errstr
+			)))
+    goto bad;
   dkim_private_key_expanded[0] = '\0';
   pdkim_set_optional(ctx,
 		      CS dkim_sign_headers_expanded,
@@ -610,11 +622,15 @@ while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep,
 		      pdkim_canon,
 		      pdkim_canon, -1, 0, 0);
 
-  lseek(dkim_fd, 0, SEEK_SET);
+  if (prefix)
+    pdkim_feed(ctx, prefix, Ustrlen(prefix));
 
-  while ((sread = read(dkim_fd, &buf, sizeof(buf))) > 0)
-    if ((pdkim_rc = pdkim_feed(ctx, buf, sread)) != PDKIM_OK)
-      goto pk_bad;
+  if (lseek(fd, off, SEEK_SET) < 0)
+    sread = -1;
+  else
+    while ((sread = read(fd, &buf, sizeof(buf))) > 0)
+      if ((pdkim_rc = pdkim_feed(ctx, buf, sread)) != PDKIM_OK)
+	goto pk_bad;
 
   /* Handle failed read above. */
   if (sread == -1)
@@ -624,7 +640,7 @@ while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep,
     goto bad;
     }
 
-  if ((pdkim_rc = pdkim_feed_finish(ctx, &signature)) != PDKIM_OK)
+  if ((pdkim_rc = pdkim_feed_finish(ctx, &signature, errstr)) != PDKIM_OK)
     goto pk_bad;
 
   sigbuf = string_append(sigbuf, &sigsize, &sigptr, 2,