From: Prasad J Pandit <p...@fedoraproject.org>
The network interface name in Linux is defined to be of size
IFNAMSIZ(=16), including the terminating null('\0') byte.
The same is applied to interface names read from 'bridge.conf'
file to form ACL rules. If user supplied '--br=bridge' name
is not restricted to the same length, it could lead to ACL bypass
issue. Restrict interface name to IFNAMSIZ, including null byte.
Reported-by: Riccardo Schirone <rschi...@redhat.com>
Signed-off-by: Prasad J Pandit <p...@fedoraproject.org>
---
qemu-bridge-helper.c | 11 +++++++++++
1 file changed, 11 insertions(+)
Reviewed v3
-> https://lists.nongnu.org/archive/html/qemu-devel/2019-07/msg00245.html
diff --git a/qemu-bridge-helper.c b/qemu-bridge-helper.c
index f9940deefd..e90c22f07d 100644
--- a/qemu-bridge-helper.c
+++ b/qemu-bridge-helper.c
@@ -109,6 +109,13 @@ static int parse_acl_file(const char *filename, ACLList
*acl_list)
}
*argend = 0;
+ if (!g_str_equal(cmd, "include") && strlen(arg) >= IFNAMSIZ) {
+ fprintf(stderr, "name `%s' too long: %zu\n", arg, strlen(arg));
+ fclose(f);
+ errno = EINVAL;
+ return -1;
+ }
+
if (strcmp(cmd, "deny") == 0) {
acl_rule = g_malloc(sizeof(*acl_rule));
if (strcmp(arg, "all") == 0) {
@@ -259,6 +266,10 @@ int main(int argc, char **argv)
usage();
return EXIT_FAILURE;
}
+ if (strlen(bridge) >= IFNAMSIZ) {
+ fprintf(stderr, "name `%s' too long: %zu\n", bridge, strlen(bridge));
+ return EXIT_FAILURE;
+ }
/* parse default acl file */
QSIMPLEQ_INIT(&acl_list);
--
2.21.0
