add_arg(): check for overflow

Fixes: #222.

diff --git a/util/mount.fuse.c b/util/mount.fuse.c
index 3f498dbb8707b936643f6a5cffa002ff3abe356a..169fe537f1f167a55258bb0d1c74c207131a1bb6 100644 (file)
--- a/util/mount.fuse.c
+++ b/util/mount.fuse.c
@@ -13,6 +13,7 @@
 #include <string.h>
 #include <unistd.h>
 #include <errno.h>
+#include <stdint.h>
 
 static char *progname;
 
@@ -40,6 +41,10 @@ static void add_arg(char **cmdp, const char *opt)
 {
        size_t optlen = strlen(opt);
        size_t cmdlen = *cmdp ? strlen(*cmdp) : 0;
+       if (optlen >= (SIZE_MAX - cmdlen - 4)/4) {
+               fprintf(stderr, "%s: argument too long\n", progname);
+               exit(1);
+       }
        char *cmd = xrealloc(*cmdp, cmdlen + optlen * 4 + 4);
        char *s;
        s = cmd + cmdlen;