diff options
| author | Florian Westphal <fw@strlen.de> | 2020-01-16 12:03:01 +0100 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2020-01-16 14:22:33 +0100 |
| commit | 335178d5429c4cee61b58f4ac80688f556630818 (patch) | |
| tree | 368c893913d4fb2b363132dac9d8692f0a2f7751 /net | |
| parent | cd77e75b5e4632d05d61fec5383052713c8ede2b (diff) | |
netfilter: nf_tables: fix flowtable list del corruption
syzbot reported following crash:
list_del corruption, ffff88808c9bb000->prev is LIST_POISON2 (dead000000000122)
[..]
Call Trace:
__list_del_entry include/linux/list.h:131 [inline]
list_del_rcu include/linux/rculist.h:148 [inline]
nf_tables_commit+0x1068/0x3b30 net/netfilter/nf_tables_api.c:7183
[..]
The commit transaction list has:
NFT_MSG_NEWTABLE
NFT_MSG_NEWFLOWTABLE
NFT_MSG_DELFLOWTABLE
NFT_MSG_DELTABLE
A missing generation check during DELTABLE processing causes it to queue
the DELFLOWTABLE operation a second time, so we corrupt the list here:
case NFT_MSG_DELFLOWTABLE:
list_del_rcu(&nft_trans_flowtable(trans)->list);
nf_tables_flowtable_notify(&trans->ctx,
because we have two different DELFLOWTABLE transactions for the same
flowtable. We then call list_del_rcu() twice for the same flowtable->list.
The object handling seems to suffer from the same bug so add a generation
check too and only queue delete transactions for flowtables/objects that
are still active in the next generation.
Reported-by: syzbot+37a6804945a3a13b1572@syzkaller.appspotmail.com
Fixes: 3b49e2e94e6eb ("netfilter: nf_tables: add flow table netlink frontend")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/netfilter/nf_tables_api.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 896a6e8aff91..65f51a2e9c2a 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -1048,12 +1048,18 @@ static int nft_flush_table(struct nft_ctx *ctx) } list_for_each_entry_safe(flowtable, nft, &ctx->table->flowtables, list) { + if (!nft_is_active_next(ctx->net, flowtable)) + continue; + err = nft_delflowtable(ctx, flowtable); if (err < 0) goto out; } list_for_each_entry_safe(obj, ne, &ctx->table->objects, list) { + if (!nft_is_active_next(ctx->net, obj)) + continue; + err = nft_delobj(ctx, obj); if (err < 0) goto out; |