From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [91.216.245.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DEE3B344D88 for ; Tue, 16 Jun 2026 19:19:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.216.245.30 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781637592; cv=none; b=A7x2kk0PWA62iNfxYBFKxs5UN4SjvEXjG754KhqBn0LtihKyV/BBLdU7E//zmUxOdFfWk5kV388Kfk31sGwyYfOZo9frKF2Dle/YO535jRLnP1KhFzUtaJ0kpGOLlX05KLDWLC3UGUStxVqAaPy7JExJSxJuPDGD5ue7KPbqc8s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781637592; c=relaxed/simple; bh=KNFVqx0LQkPsCuIxy6ZaxpKoJWzOj7uv6ouedO9Ro3c=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=UkZu86PQJT4hJNG4UV6sEOADSKr1Q8ioykcK/u3dkcMczSJweMaaWWBmwnA3ApMSLEhaXJQTwGinaxbenWnMYEd/vZJ37WmiwBysLq/edpqFDUaX9+DxwFxH3J34NeWDmwEeMwyUc3vGcX4LMrNcnUW9JLVkwVwIj9uNtQa2Cuo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de; spf=pass smtp.mailfrom=Chamillionaire.breakpoint.cc; arc=none smtp.client-ip=91.216.245.30 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=Chamillionaire.breakpoint.cc Received: by Chamillionaire.breakpoint.cc (Postfix, from userid 1003) id 910F360541; Tue, 16 Jun 2026 21:19:48 +0200 (CEST) From: Florian Westphal To: Cc: Florian Westphal , Seesee , Stefano Brivio Subject: [PATCH nf] netfilter: nft_set_pipapo: don't leak bad clone into future transaction Date: Tue, 16 Jun 2026 21:19:34 +0200 Message-ID: <20260616191938.2875-1-fw@strlen.de> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: netfilter-devel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On memory allocation failure the cloned nft_pipapo_match can enter a bad state: - some fields can have their lookup tables resized while others did not - bits might have been toggled - scratch map can be undersized which also means m->bsize_max can be lower than what is required This means that the next insertion in the same batch can trigger out-of-bounds writes. Futhermore, a failure in the first can result in the bad clone to leak into the next transaction because the abort callback is never executed in this case (the upper layer saw an error and no attempt to allocate a transactional request was made). Record a state for the nft_pipapo_match structure: - NEW (pristine clone) - MOD (modified clone with good state) - ERR (potentially bogus content) Then make it so that deletes and insertions fail when the clone entered ERR state. In case the very first insert attempt results in an error, free the clone right away. Reported-by: Seesee Cc: Stefano Brivio Fixes: 3c4287f62044 ("nf_tables: Add set type for arbitrary concatenation of ranges") Signed-off-by: Florian Westphal --- For some reason reporter did not share a PoC despite claiming there is one, so I have no fucking clue if this patch is correct or not, its based on guesswork without any validation. net/netfilter/nft_set_pipapo.c | 34 +++++++++++++++++++++++++++++----- net/netfilter/nft_set_pipapo.h | 8 ++++++++ 2 files changed, 37 insertions(+), 5 deletions(-) diff --git a/net/netfilter/nft_set_pipapo.c b/net/netfilter/nft_set_pipapo.c index 50d4a4f04309..61b8601ee377 100644 --- a/net/netfilter/nft_set_pipapo.c +++ b/net/netfilter/nft_set_pipapo.c @@ -342,6 +342,8 @@ #include "nft_set_pipapo_avx2.h" #include "nft_set_pipapo.h" +static void nft_pipapo_abort(const struct nft_set *set); + /** * pipapo_refill() - For each set bit, set bits from selected mapping table item * @map: Bitmap to be scanned for set bits @@ -1296,7 +1298,7 @@ static int nft_pipapo_insert(const struct net *net, const struct nft_set *set, const u8 *start_p, *end_p; int i, bsize_max, err = 0; - if (!m) + if (!m || m->state == NFT_PIPAPO_CLONE_ERR) return -ENOMEM; if (nft_set_ext_exists(ext, NFT_SET_EXT_KEY_END)) @@ -1367,8 +1369,10 @@ static int nft_pipapo_insert(const struct net *net, const struct nft_set *set, else ret = pipapo_expand(f, start, end, f->groups * f->bb); - if (ret < 0) - return ret; + if (ret < 0) { + err = ret; + goto abort; + } if (f->bsize > bsize_max) bsize_max = f->bsize; @@ -1384,7 +1388,7 @@ static int nft_pipapo_insert(const struct net *net, const struct nft_set *set, err = pipapo_realloc_scratch(m, bsize_max); if (err) - return err; + goto abort; m->bsize_max = bsize_max; } else { @@ -1396,7 +1400,26 @@ static int nft_pipapo_insert(const struct net *net, const struct nft_set *set, pipapo_map(m, rulemap, e); + m->state = NFT_PIPAPO_CLONE_MOD; return 0; +abort: + DEBUG_NET_WARN_ON_ONCE(m->state == NFT_PIPAPO_CLONE_ERR); + + /* Two rollback cases: + * 1) no previous changes. nft_pipapo_abort is not + * guaranteed to be invoked (there might be no further + * add/delete requests coming after this). + * + * 2) we had previous changes: there are transaction + * records pointing to this set. Leave the rollback to + * the transaction handling. + */ + if (m->state == NFT_PIPAPO_CLONE_NEW) + nft_pipapo_abort(set); /* releases m */ + else + m->state = NFT_PIPAPO_CLONE_ERR; + + return err; } /** @@ -1473,6 +1496,7 @@ static struct nft_pipapo_match *pipapo_clone(struct nft_pipapo_match *old) dst++; } + new->state = NFT_PIPAPO_CLONE_NEW; return new; out_mt: @@ -1896,7 +1920,7 @@ nft_pipapo_deactivate(const struct net *net, const struct nft_set *set, /* removal must occur on priv->clone, if we are low on memory * we have no choice and must fail the removal request. */ - if (!m) + if (!m || m->state == NFT_PIPAPO_CLONE_ERR) return NULL; e = pipapo_get(m, (const u8 *)elem->key.val.data, diff --git a/net/netfilter/nft_set_pipapo.h b/net/netfilter/nft_set_pipapo.h index b82abb03576e..a19e980d06ef 100644 --- a/net/netfilter/nft_set_pipapo.h +++ b/net/netfilter/nft_set_pipapo.h @@ -131,9 +131,16 @@ struct nft_pipapo_scratch { unsigned long __map[]; }; +enum nft_pipapo_clone_state { + NFT_PIPAPO_CLONE_NEW, + NFT_PIPAPO_CLONE_MOD, + NFT_PIPAPO_CLONE_ERR, +}; + /** * struct nft_pipapo_match - Data used for lookup and matching * @field_count: Amount of fields in set + * @state: add/delete state; used from control plane * @bsize_max: Maximum lookup table bucket size of all fields, in longs * @scratch: Preallocated per-CPU maps for partial matching results * @rcu: Matching data is swapped on commits @@ -141,6 +148,7 @@ struct nft_pipapo_scratch { */ struct nft_pipapo_match { u8 field_count; + enum nft_pipapo_clone_state state:8; unsigned int bsize_max; struct nft_pipapo_scratch * __percpu *scratch; struct rcu_head rcu; -- 2.53.0