Check return value of snprintf().

[tlsproxy/tlsproxy.git] / src / verify.c

diff --git a/src/verify.c b/src/verify.c
index 4cd9d503d791ae3c427c7ffe3e845037897747cd..63ca6da2d982a121d36cb8b6779e795ba0c72f30 100644 (file)
--- a/src/verify.c
+++ b/src/verify.c
@@ -111,6 +111,7 @@ int verify_tls_connection(gnutls_session_t session, const char *hostname) {
 
     /* Open stored server certificate file. */
     if (0 != server_certificate_path(&file, hostname, path, sizeof(path))) {
+        LOG(LOG_DEBUG, "server certificate:\n%s", server_cert);
         return -1;
     }
 
@@ -121,9 +122,10 @@ int verify_tls_connection(gnutls_session_t session, const char *hostname) {
         size += strlen(buffer);
         /* Make sure the buffer is big enough. */
         if (sizeof(stored_cert) <= size) {
-            LOG(LOG_WARNING, "verify_tls_connection(): '%s' too big",
-                path);
+            LOG(LOG_WARNING, "verify_tls_connection(): '%s' too big", path);
             fclose(file);
+
+            LOG(LOG_DEBUG, "server certificate:\n%s", server_cert);
             return -1;
         }
 
@@ -134,6 +136,8 @@ int verify_tls_connection(gnutls_session_t session, const char *hostname) {
         LOG(LOG_WARNING,
             "verify_tls_connection(): failed to read from '%s': %s",
             path, strerror(errno));
+
+        LOG(LOG_DEBUG, "server certificate:\n%s", server_cert);
         return -1;
     }
     fclose(file);
@@ -143,13 +147,18 @@ int verify_tls_connection(gnutls_session_t session, const char *hostname) {
         LOG(LOG_ERROR,
             "verify_tls_connection(): server certificate changed!",
             path, strerror(errno));
+
+        LOG(LOG_WARNING, "server certificate:\n%s", server_cert);
         return -2;
     }
 
     return 0;
 }
 
-int server_certificate_path(FILE **file, const char *hostname, char *path, size_t size) {
+int server_certificate_path(FILE **file, const char *hostname,
+                            char *path, size_t size) {
+    int result;
+
     /* Hostname too long. */
     if (size - strlen(STORED_SERVER_CERT_FORMAT) <= strlen(hostname)) {
         LOG(LOG_WARNING,
@@ -164,14 +173,29 @@ int server_certificate_path(FILE **file, const char *hostname, char *path, size_
             hostname);
         return -1;
     }
-    snprintf(path, size, STORED_SERVER_CERT_FORMAT, hostname);
+    result = snprintf(path, size, STORED_SERVER_CERT_FORMAT, hostname);
+    if (result < 0) {
+        LOG_PERROR(LOG_ERROR,
+                   "server_certificate_path(): snprintf failed");
+        return -1;
+    } else if ((size_t)result >= size) {
+        LOG(LOG_ERROR,
+            "server_certificate_path(): snprintf buffer too short");
+        return -1;
+    }
 
     /* Open the stored certificate file. */
     *file = fopen(path, "rb");
     if (NULL == *file) {
-        LOG(global_passthrough_unknown ? LOG_DEBUG : LOG_WARNING,
-            "server_certificate_path(): failed to open '%s': %s",
-            path, strerror(errno));
+        if (global_passthrough_unknown) {
+            LOG(LOG_DEBUG,
+                "server_certificate_path(): failed to open '%s': %s",
+                path, strerror(errno));
+        } else {
+            LOG(LOG_WARNING,
+                "server_certificate_path(): failed to open '%s': %s",
+                path, strerror(errno));
+        }
         /* Couldn't open the file, special case. */
         return -2;
     }