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commit 40e9f174512ac8582e3c90b6a933996bf28a347f
parent ae830af68c1331c3cd97c203157f53d6248a5b13
Author: Christian Grothoff <grothoff@gnunet.org>
Date:   Sun, 16 Aug 2026 08:26:56 +0200

better input validation on UNIXPATH_MODE

Diffstat:
M
src/mhd/mhd_config.c
 | 
35
+++++++++++++++++++++++------------

1 file changed, 23 insertions(+), 12 deletions(-)
diff --git a/src/mhd/mhd_config.c b/src/mhd/mhd_config.c
@@ -327,19 +327,30 @@ TALER_MHD_listen_bind (const struct GNUNET_CONFIGURATION_Handle *cfg,
       GNUNET_free (serve_unixpath);
       return GNUNET_SYSERR;
     }
-    errno = 0;
-    unixpath_mode = (mode_t) strtoul (modestring,
-                                      NULL,
-                                      8);
-    if (0 != errno)
     {
-      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
-                                 section,
-                                 "UNIXPATH_MODE",
-                                 "must be octal number");
-      GNUNET_free (modestring);
-      GNUNET_free (serve_unixpath);
-      return GNUNET_SYSERR;
+      char *endp;
+      unsigned long mode;
+
+      errno = 0;
+      mode = strtoul (modestring,
+                      &endp,
+                      8);
+      /* strtoul() only sets errno on overflow, so we must
+         also check that we actually consumed the entire value */
+      if ( (0 != errno) ||
+           (endp == modestring) ||
+           ('\0' != *endp) ||
+           (mode != (unsigned long) (mode_t) mode) )
+      {
+        GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
+                                   section,
+                                   "UNIXPATH_MODE",
+                                   "must be octal number");
+        GNUNET_free (modestring);
+        GNUNET_free (serve_unixpath);
+        return GNUNET_SYSERR;
+      }
+      unixpath_mode = (mode_t) mode;
     }
     GNUNET_free (modestring);