From: Florian Westphal fw@strlen.de
[ 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@strlen.de Signed-off-by: Sasha Levin sashal@kernel.org --- net/netfilter/nf_tables_api.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index b016ae68d9db8..68a13ab584acf 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -5852,6 +5852,9 @@ 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) {