summaryrefslogtreecommitdiffstats
path: root/net/bridge
diff options
context:
space:
mode:
authorFlorian Westphal <fw@strlen.de>2023-02-17 23:20:06 +0100
committerPablo Neira Ayuso <pablo@netfilter.org>2023-02-22 00:22:31 +0100
commite58a171d35e32e6e8c37cfe0e8a94406732a331f (patch)
tree36765ffc5190d73d9b1942b55cc225bb59cb2fb7 /net/bridge
parentnetfilter: ip6t_rpfilter: Fix regression with VRF interfaces (diff)
downloadlinux-e58a171d35e32e6e8c37cfe0e8a94406732a331f.tar.xz
linux-e58a171d35e32e6e8c37cfe0e8a94406732a331f.zip
netfilter: ebtables: fix table blob use-after-free
We are not allowed to return an error at this point. Looking at the code it looks like ret is always 0 at this point, but its not. t = find_table_lock(net, repl->name, &ret, &ebt_mutex); ... this can return a valid table, with ret != 0. This bug causes update of table->private with the new blob, but then frees the blob right away in the caller. Syzbot report: BUG: KASAN: vmalloc-out-of-bounds in __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168 Read of size 4 at addr ffffc90005425000 by task kworker/u4:4/74 Workqueue: netns cleanup_net Call Trace: kasan_report+0xbf/0x1f0 mm/kasan/report.c:517 __ebt_unregister_table+0xc00/0xcd0 net/bridge/netfilter/ebtables.c:1168 ebt_unregister_table+0x35/0x40 net/bridge/netfilter/ebtables.c:1372 ops_exit_list+0xb0/0x170 net/core/net_namespace.c:169 cleanup_net+0x4ee/0xb10 net/core/net_namespace.c:613 ... ip(6)tables appears to be ok (ret should be 0 at this point) but make this more obvious. Fixes: c58dd2dd443c ("netfilter: Can't fail and free after table replacement") Reported-by: syzbot+f61594de72d6705aea03@syzkaller.appspotmail.com Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/bridge')
-rw-r--r--net/bridge/netfilter/ebtables.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index ce5dfa3babd2..757ec46fc45a 100644
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -1090,7 +1090,7 @@ static int do_replace_finish(struct net *net, struct ebt_replace *repl,
audit_log_nfcfg(repl->name, AF_BRIDGE, repl->nentries,
AUDIT_XT_OP_REPLACE, GFP_KERNEL);
- return ret;
+ return 0;
free_unlock:
mutex_unlock(&ebt_mutex);