Add a log line for each TLS connection received, identifying the cano…

…nical name present in the certificate of the peer

tls.c

@@ -480,6 +480,36 @@ void tlsserverrd(struct client *client) {
     debug(DBG_DBG, "tlsserverrd: reader for %s exiting", addr2string(client->addr, tmp, sizeof(tmp)));
 }
 
+/* Returns the CN from the certificate subject as a malloc'ed char array
+ * Doesn't support non ASCII characters!
+ * BEWARE char* needs to be free() after use! 
+ * based on the code from cnregexp() at tlscommon.c
+ * by pribeiro@net.ipl.pt DSIC/IPL */
+static char *malloced_cnfromcert(X509 *cert) {
+    int loc, l;
+    char *v;
+    X509_NAME *nm;
+    X509_NAME_ENTRY *e;
+    ASN1_STRING *t;
+
+    nm = X509_get_subject_name(cert);
+    loc = -1;
+    for (;;) {
+        loc = X509_NAME_get_index_by_NID(nm, NID_commonName, loc);
+        if (loc == -1)
+            break;
+        e = X509_NAME_get_entry(nm, loc);
+        t = X509_NAME_ENTRY_get_data(e);
+        v = (char *) ASN1_STRING_get0_data(t);
+        l = ASN1_STRING_length(t);
+        if (l < 0)
+            continue;
+        return stringcopy((char *)v, l);
+    }
+    /* not found */
+    return NULL;
+}
+
 void *tlsservernew(void *arg) {
     int s, origflags;
     struct sockaddr_storage from;
@@ -538,6 +568,12 @@ void *tlsservernew(void *arg) {
 
     while (conf) {
         if (accepted_tls == conf->tlsconf && verifyconfcert(cert, conf)) {
+            char *cn = malloced_cnfromcert(cert);
+            if(cn) {
+                debug(DBG_WARN, "tlsservernew: from %s, host %s, cert CN %s",
+                    addr2string((struct sockaddr *)&from,tmp, sizeof(tmp)), conf->name, cn);
+                free(cn);
+            }
             X509_free(cert);
             client = addclient(conf, 1);
             if (client) {