Fix DKIM record parsing to comply to RFC 6376

* src/dkim.c (dkim_signature_parse,dnsrec_parse): Allow for FWS
as per RFC 6376, section 3.2

1 files changed, 16 insertions, 2 deletions

diff --git a/src/dkim.c b/src/dkim.c
index 18ad159b..8bf7c906 100644
--- a/src/dkim.c
+++ b/src/dkim.c
@@ -582,7 +582,15 @@ dkim_signature_parse(char *str, struct dkim_signature *ret_sig)
 	int i;
 	int rc = 0;
 	struct dkim_signature sig;
-	
+
+	/*
+	 * tag-list  =  tag-spec *( ";" tag-spec ) [ ";" ]
+	 * tag-spec  =  [FWS] tag-name [FWS] "=" [FWS] tag-value [FWS]
+	 *
+	 * The mu_wordsplit call splits the value on ';' and removes
+	 * whitespace at both sides of each token.  Internal FWS (around
+	 * the equals sign) is removed later.
+	 */
 	ws.ws_delim = ";";
 	rc = mu_wordsplit(str,
 			  &ws,
@@ -605,6 +613,10 @@ dkim_signature_parse(char *str, struct dkim_signature *ret_sig)
 			goto end;
 		}
 		*p++ = 0;
+		/* Remove internal FWS */
+		mu_rtrim_class(k, MU_CTYPE_BLANK);
+		mu_ltrim_class(p, MU_CTYPE_BLANK);
+		/* Handle known tags */
 		if (strcmp(k, "a") == 0) {
 			sig.a = (char*) mu_strdup(p);
 		} else if (strcmp(k, "b") == 0) {
@@ -1253,7 +1265,9 @@ dnsrec_parse(char *rec, mu_assoc_t *pa)
 				break;
 			}
 			*p++ = 0;
-				
+			mu_rtrim_class(ws.ws_wordv[i], MU_CTYPE_BLANK);
+			mu_ltrim_class(p, MU_CTYPE_BLANK);
+			
 			rc = mu_assoc_install_ref(a, ws.ws_wordv[i], &slot);
 			if (rc == ENOMEM)
 				mu_alloc_die ();