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| author | Florian Westphal <fw@strlen.de> | 2024-07-02 17:08:14 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-07-11 13:51:12 +0300 |
| commit | 09e650c3a3a7d804430260510534ccbf71c75b2e (patch) | |
| tree | 76b4da9a23cec5f09789119c9484fcab5c6ed8bf /net/netfilter/nf_tables_api.c | |
| parent | 484dd545271d02d1571e1c6b62ea7df9dbe5e692 (diff) | |
| download | linux-09e650c3a3a7d804430260510534ccbf71c75b2e.tar.xz | |
netfilter: nf_tables: unconditionally flush pending work before notifier
[ Upstream commit 9f6958ba2e902f9820c594869bd710ba74b7c4c0 ]
syzbot reports:
KASAN: slab-uaf in nft_ctx_update include/net/netfilter/nf_tables.h:1831
KASAN: slab-uaf in nft_commit_release net/netfilter/nf_tables_api.c:9530
KASAN: slab-uaf int nf_tables_trans_destroy_work+0x152b/0x1750 net/netfilter/nf_tables_api.c:9597
Read of size 2 at addr ffff88802b0051c4 by task kworker/1:1/45
[..]
Workqueue: events nf_tables_trans_destroy_work
Call Trace:
nft_ctx_update include/net/netfilter/nf_tables.h:1831 [inline]
nft_commit_release net/netfilter/nf_tables_api.c:9530 [inline]
nf_tables_trans_destroy_work+0x152b/0x1750 net/netfilter/nf_tables_api.c:9597
Problem is that the notifier does a conditional flush, but its possible
that the table-to-be-removed is still referenced by transactions being
processed by the worker, so we need to flush unconditionally.
We could make the flush_work depend on whether we found a table to delete
in nf-next to avoid the flush for most cases.
AFAICS this problem is only exposed in nf-next, with
commit e169285f8c56 ("netfilter: nf_tables: do not store nft_ctx in transaction objects"),
with this commit applied there is an unconditional fetch of
table->family which is whats triggering the above splat.
Fixes: 2c9f0293280e ("netfilter: nf_tables: flush pending destroy work before netlink notifier")
Reported-and-tested-by: syzbot+4fd66a69358fc15ae2ad@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=4fd66a69358fc15ae2ad
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'net/netfilter/nf_tables_api.c')
| -rw-r--r-- | net/netfilter/nf_tables_api.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index faa77b031d1f..0f77ba3306c2 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -11479,8 +11479,7 @@ static int nft_rcv_nl_event(struct notifier_block *this, unsigned long event, gc_seq = nft_gc_seq_begin(nft_net); - if (!list_empty(&nf_tables_destroy_list)) - nf_tables_trans_destroy_flush_work(); + nf_tables_trans_destroy_flush_work(); again: list_for_each_entry(table, &nft_net->tables, list) { if (nft_table_has_owner(table) && |