This is a note to let you know that I've just added the patch titled
netfilter: nf_tables: fix spurious set element insertion failure
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
netfilter-nf_tables-fix-spurious-set-element-inserti.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 949a1f70d02ec54cf43534a8d2eff243dcb11238
Author: Florian Westphal <fw@xxxxxxxxx>
Date: Thu Jul 20 00:29:58 2023 +0200
netfilter: nf_tables: fix spurious set element insertion failure
[ Upstream commit ddbd8be68941985f166f5107109a90ce13147c44 ]
On some platforms there is a padding hole in the nft_verdict
structure, between the verdict code and the chain pointer.
On element insertion, if the new element clashes with an existing one and
NLM_F_EXCL flag isn't set, we want to ignore the -EEXIST error as long as
the data associated with duplicated element is the same as the existing
one. The data equality check uses memcmp.
For normal data (NFT_DATA_VALUE) this works fine, but for NFT_DATA_VERDICT
padding area leads to spurious failure even if the verdict data is the
same.
This then makes the insertion fail with 'already exists' error, even
though the new "key : data" matches an existing entry and userspace
told the kernel that it doesn't want to receive an error indication.
Fixes: c016c7e45ddf ("netfilter: nf_tables: honor NLM_F_EXCL flag in set element insertion")
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index d56f5d7fa5455..9c3a9e3f1ede9 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -8914,6 +8914,9 @@ static int nft_verdict_init(const struct nft_ctx *ctx, struct nft_data *data,
if (!tb[NFTA_VERDICT_CODE])
return -EINVAL;
+
+ /* zero padding hole for memcmp */
+ memset(data, 0, sizeof(*data));
data->verdict.code = ntohl(nla_get_be32(tb[NFTA_VERDICT_CODE]));
switch (data->verdict.code) {
