src/freon.c: Check before extracting mode in open

Fixes #3140
dnschneid · Nov 20, 2017 · 51ffe99 · 51ffe99
1 parent 99877ea
commit 51ffe99
Showing 1 changed file with 7 additions and 2 deletions.
diff --git a/src/freon.c b/src/freon.c
@@ -10,6 +10,7 @@
 
 #define _GNU_SOURCE
 #include <dlfcn.h>
+#include <fcntl.h>
 #include <stdio.h>
 #include <sys/file.h>
 #include <sys/types.h>
@@ -228,9 +229,11 @@ static int _open(int (*origfunc)(const char *pathname, int flags, mode_t mode),
 int open(const char *pathname, int flags, ...) {
     if (!orig_open) preload_init();
 
+    mode_t mode = 0;
     va_list argp;
     va_start(argp, flags);
-    mode_t mode = va_arg(argp, mode_t);
+    if (flags & (O_CREAT | O_TMPFILE))
+        mode = va_arg(argp, mode_t);
     va_end(argp);
 
     return _open(orig_open, "open", pathname, flags, mode);
@@ -239,9 +242,11 @@ int open(const char *pathname, int flags, ...) {
 int open64(const char *pathname, int flags, ...) {
     if (!orig_open64) preload_init();
 
+    mode_t mode = 0;
     va_list argp;
     va_start(argp, flags);
-    mode_t mode = va_arg(argp, mode_t);
+    if (flags & (O_CREAT | O_TMPFILE))
+        mode = va_arg(argp, mode_t);
     va_end(argp);
 
     return _open(orig_open64, "open64", pathname, flags, mode);