From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netfilter-devel@vger.kernel.org
Cc: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org,
pabeni@redhat.com, edumazet@google.com, fw@strlen.de,
horms@kernel.org
Subject: [PATCH net 01/12] netfilter: nft_set_pipapo_avx2: don't return non-matching entry on expiry
Date: Thu, 26 Mar 2026 13:51:42 +0100 [thread overview]
Message-ID: <20260326125153.685915-2-pablo@netfilter.org> (raw)
In-Reply-To: <20260326125153.685915-1-pablo@netfilter.org>
From: Florian Westphal <fw@strlen.de>
New test case fails unexpectedly when avx2 matching functions are used.
The test first loads a ranomly generated pipapo set
with 'ipv4 . port' key, i.e. nft -f foo.
This works. Then, it reloads the set after a flush:
(echo flush set t s; cat foo) | nft -f -
This is expected to work, because its the same set after all and it was
already loaded once.
But with avx2, this fails: nft reports a clashing element.
The reported clash is of following form:
We successfully re-inserted
a . b
c . d
Then we try to insert a . d
avx2 finds the already existing a . d, which (due to 'flush set') is marked
as invalid in the new generation. It skips the element and moves to next.
Due to incorrect masking, the skip-step finds the next matching
element *only considering the first field*,
i.e. we return the already reinserted "a . b", even though the
last field is different and the entry should not have been matched.
No such error is reported for the generic c implementation (no avx2) or when
the last field has to use the 'nft_pipapo_avx2_lookup_slow' fallback.
Bisection points to
7711f4bb4b36 ("netfilter: nft_set_pipapo: fix range overlap detection")
but that fix merely uncovers this bug.
Before this commit, the wrong element is returned, but erronously
reported as a full, identical duplicate.
The root-cause is too early return in the avx2 match functions.
When we process the last field, we should continue to process data
until the entire input size has been consumed to make sure no stale
bits remain in the map.
Link: https://lore.kernel.org/netfilter-devel/20260321152506.037f68c0@elisabeth/
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
net/netfilter/nft_set_pipapo_avx2.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/net/netfilter/nft_set_pipapo_avx2.c b/net/netfilter/nft_set_pipapo_avx2.c
index 7ff90325c97f..6395982e4d95 100644
--- a/net/netfilter/nft_set_pipapo_avx2.c
+++ b/net/netfilter/nft_set_pipapo_avx2.c
@@ -242,7 +242,7 @@ static int nft_pipapo_avx2_lookup_4b_2(unsigned long *map, unsigned long *fill,
b = nft_pipapo_avx2_refill(i_ul, &map[i_ul], fill, f->mt, last);
if (last)
- return b;
+ ret = b;
if (unlikely(ret == -1))
ret = b / XSAVE_YMM_SIZE;
@@ -319,7 +319,7 @@ static int nft_pipapo_avx2_lookup_4b_4(unsigned long *map, unsigned long *fill,
b = nft_pipapo_avx2_refill(i_ul, &map[i_ul], fill, f->mt, last);
if (last)
- return b;
+ ret = b;
if (unlikely(ret == -1))
ret = b / XSAVE_YMM_SIZE;
@@ -414,7 +414,7 @@ static int nft_pipapo_avx2_lookup_4b_8(unsigned long *map, unsigned long *fill,
b = nft_pipapo_avx2_refill(i_ul, &map[i_ul], fill, f->mt, last);
if (last)
- return b;
+ ret = b;
if (unlikely(ret == -1))
ret = b / XSAVE_YMM_SIZE;
@@ -505,7 +505,7 @@ static int nft_pipapo_avx2_lookup_4b_12(unsigned long *map, unsigned long *fill,
b = nft_pipapo_avx2_refill(i_ul, &map[i_ul], fill, f->mt, last);
if (last)
- return b;
+ ret = b;
if (unlikely(ret == -1))
ret = b / XSAVE_YMM_SIZE;
@@ -641,7 +641,7 @@ static int nft_pipapo_avx2_lookup_4b_32(unsigned long *map, unsigned long *fill,
b = nft_pipapo_avx2_refill(i_ul, &map[i_ul], fill, f->mt, last);
if (last)
- return b;
+ ret = b;
if (unlikely(ret == -1))
ret = b / XSAVE_YMM_SIZE;
@@ -699,7 +699,7 @@ static int nft_pipapo_avx2_lookup_8b_1(unsigned long *map, unsigned long *fill,
b = nft_pipapo_avx2_refill(i_ul, &map[i_ul], fill, f->mt, last);
if (last)
- return b;
+ ret = b;
if (unlikely(ret == -1))
ret = b / XSAVE_YMM_SIZE;
@@ -764,7 +764,7 @@ static int nft_pipapo_avx2_lookup_8b_2(unsigned long *map, unsigned long *fill,
b = nft_pipapo_avx2_refill(i_ul, &map[i_ul], fill, f->mt, last);
if (last)
- return b;
+ ret = b;
if (unlikely(ret == -1))
ret = b / XSAVE_YMM_SIZE;
@@ -839,7 +839,7 @@ static int nft_pipapo_avx2_lookup_8b_4(unsigned long *map, unsigned long *fill,
b = nft_pipapo_avx2_refill(i_ul, &map[i_ul], fill, f->mt, last);
if (last)
- return b;
+ ret = b;
if (unlikely(ret == -1))
ret = b / XSAVE_YMM_SIZE;
@@ -925,7 +925,7 @@ static int nft_pipapo_avx2_lookup_8b_6(unsigned long *map, unsigned long *fill,
b = nft_pipapo_avx2_refill(i_ul, &map[i_ul], fill, f->mt, last);
if (last)
- return b;
+ ret = b;
if (unlikely(ret == -1))
ret = b / XSAVE_YMM_SIZE;
@@ -1019,7 +1019,7 @@ static int nft_pipapo_avx2_lookup_8b_16(unsigned long *map, unsigned long *fill,
b = nft_pipapo_avx2_refill(i_ul, &map[i_ul], fill, f->mt, last);
if (last)
- return b;
+ ret = b;
if (unlikely(ret == -1))
ret = b / XSAVE_YMM_SIZE;
--
2.47.3
next prev parent reply other threads:[~2026-03-26 12:52 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-26 12:51 [PATCH net,v3 00/12] Netfilter for net Pablo Neira Ayuso
2026-03-26 12:51 ` Pablo Neira Ayuso [this message]
2026-03-26 12:51 ` [PATCH net 02/12] selftests: netfilter: nft_concat_range.sh: add check for flush+reload bug Pablo Neira Ayuso
2026-03-26 12:51 ` [PATCH net 03/12] netfilter: nfnetlink_log: fix uninitialized padding leak in NFULA_PAYLOAD Pablo Neira Ayuso
2026-03-26 12:51 ` [PATCH net 04/12] netfilter: ip6t_rt: reject oversized addrnr in rt_mt6_check() Pablo Neira Ayuso
2026-03-26 12:51 ` [PATCH net 05/12] netfilter: nft_set_rbtree: revisit array resize logic Pablo Neira Ayuso
2026-03-26 12:51 ` [PATCH net 06/12] netfilter: nf_conntrack_expect: honor expectation helper field Pablo Neira Ayuso
2026-03-26 12:51 ` [PATCH net 07/12] netfilter: nf_conntrack_expect: use expect->helper Pablo Neira Ayuso
2026-03-26 12:51 ` [PATCH net 08/12] netfilter: ctnetlink: ensure safe access to master conntrack Pablo Neira Ayuso
2026-03-26 12:51 ` [PATCH net 09/12] netfilter: nf_conntrack_expect: store netns and zone in expectation Pablo Neira Ayuso
2026-03-26 12:51 ` [PATCH net 10/12] netfilter: nf_conntrack_expect: skip expectations in other netns via proc Pablo Neira Ayuso
2026-03-26 12:51 ` [PATCH net 11/12] netfilter: nf_conntrack_sip: fix use of uninitialized rtp_addr in process_sdp Pablo Neira Ayuso
2026-03-26 12:51 ` [PATCH net 12/12] netfilter: ctnetlink: use netlink policy range checks Pablo Neira Ayuso
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260326125153.685915-2-pablo@netfilter.org \
--to=pablo@netfilter.org \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=fw@strlen.de \
--cc=horms@kernel.org \
--cc=kuba@kernel.org \
--cc=netdev@vger.kernel.org \
--cc=netfilter-devel@vger.kernel.org \
--cc=pabeni@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox