Description: Check for null bytes in CN/subjAltName
Origin: http://www.openwall.com/lists/oss-security/2010/06/14/4
Author: Ludwig Nussel <ludwig.nussel@suse.de>
Bug-Debian: http://bugs.debian.org/587445

--- w3m-0.5.2.orig/istream.c
+++ w3m-0.5.2/istream.c
@@ -447,8 +447,17 @@ ssl_check_cert_ident(X509 * x, char *hos
 
 		    if (!seen_dnsname)
 			seen_dnsname = Strnew();
+		    /* replace \0 to make full string visible to user */
+		    if (sl != strlen(sn)) {
+			int i;
+			for (i = 0; i < sl; ++i) {
+			    if (!sn[i])
+				sn[i] = '!';
+			}
+		    }
 		    Strcat_m_charp(seen_dnsname, sn, " ", NULL);
-		    if (ssl_match_cert_ident(sn, sl, hostname))
+		    if (sl == strlen(sn) /* catch \0 in SAN */
+			&& ssl_match_cert_ident(sn, sl, hostname))
 			break;
 		}
 	    }
@@ -466,16 +475,27 @@ ssl_check_cert_ident(X509 * x, char *hos
     if (match_ident == FALSE && ret == NULL) {
 	X509_NAME *xn;
 	char buf[2048];
+	int slen;
 
 	xn = X509_get_subject_name(x);
 
-	if (X509_NAME_get_text_by_NID(xn, NID_commonName,
-				      buf, sizeof(buf)) == -1)
+	slen = X509_NAME_get_text_by_NID(xn, NID_commonName, buf, sizeof(buf));
+	if ( slen == -1)
 	    /* FIXME: gettextize? */
 	    ret = Strnew_charp("Unable to get common name from peer cert");
-	else if (!ssl_match_cert_ident(buf, strlen(buf), hostname))
+	else if (slen != strlen(buf)
+		|| !ssl_match_cert_ident(buf, strlen(buf), hostname)) {
+	    /* replace \0 to make full string visible to user */
+	    if (slen != strlen(buf)) {
+		int i;
+		for (i = 0; i < slen; ++i) {
+		    if (!buf[i])
+			buf[i] = '!';
+		}
+	    }
 	    /* FIXME: gettextize? */
 	    ret = Sprintf("Bad cert ident %s from %s", buf, hostname);
+	}
 	else
 	    match_ident = TRUE;
     }