From 6f5d8671225dc77190647f18a27a0d156d4ca97a Mon Sep 17 00:00:00 2001
From: Prasad J Pandit <pjp@fedoraproject.org>
Date: Tue, 23 Jul 2019 16:17:52 +0530
Subject: [PATCH 1/2] qemu-bridge-helper: restrict interface name to IFNAMSIZ
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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.

This patch fixes CVE-2019-13164.

Reported-by: Riccardo Schirone <rschiron@redhat.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Li Qiang <liq3ea@gmail.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
(cherry-picked from commit 6f5d8671225dc77190647f18a27a0d156d4ca97a)
---
 qemu-bridge-helper.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/qemu-bridge-helper.c b/qemu-bridge-helper.c
index 95624bc300..2058e10454 100644
--- a/qemu-bridge-helper.c
+++ b/qemu-bridge-helper.c
@@ -119,6 +119,13 @@ 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) {
@@ -269,6 +276,10 @@ 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);
-- 
2.19.1

