From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 F1BFC40315E; Wed, 20 May 2026 18:49:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779302956; cv=none; b=sJx+5cky+mfD1RMr9hWpVNxrp7FInKF8jwIxIHFtc0yryebktNNdAvCTpdz3qbIysm6FMHL/1Q39eeT2oZRdAaVjVb9w0ddmNM911TjAHAiSd5rTDmqLFL99254nSUL9nLXskpP4p+KXnjJo2ypyGBiiYRHaZR4tutQB5w/AN/A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779302956; c=relaxed/simple; bh=cyq466VDDgWbCofvKSKrfoL0QfLs7+krejn5ggRWfOo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IOOW0QSweNQfbH2noXwskhuzw+0THZXIal8ycSNlgmnMWAUyl7ke1uOEBdSv4QV2ycjLI1SqpZYplxK9tsqSVV6g3rbnYcOHZGQVFTxjFy3MjCGEHrnYMbXQ0RhHjXhe3wRyRKe2fAz9w8EUAC9gvt9VgFO0A5RmOeeuPHjxL30= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=vberfzya; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="vberfzya" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4AA081F00893; Wed, 20 May 2026 18:49:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779302953; bh=YMrTVCDsp1v+w06FhuFiDapu9M2NH5IKe5kVJzWX+zs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=vberfzyarp0KnoXhTlsElfhJWsGMl8VV6s9ysZ+Pzurm8sw3Rii46VRAYJ+2wbVe4 KRa1Yn4DrT4fcueG4Js2/3kTGd8A9DKL7PIjZZKu2AXHsIVPFKj6Jq7qhVViTujikc XQV3HGJGBdaTe6PCIy0DXsrJn8Alyxy6BXfGZSa0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Inseo An , Pablo Neira Ayuso , Florian Westphal , Li hongliang <1468888505@139.com>, Sasha Levin Subject: [PATCH 6.6 462/508] netfilter: nf_tables: unconditionally bump set->nelems before insertion Date: Wed, 20 May 2026 18:24:45 +0200 Message-ID: <20260520162108.608447515@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520162058.573354582@linuxfoundation.org> References: <20260520162058.573354582@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pablo Neira Ayuso [ Upstream commit def602e498a4f951da95c95b1b8ce8ae68aa733a ] In case that the set is full, a new element gets published then removed without waiting for the RCU grace period, while RCU reader can be walking over it already. To address this issue, add the element transaction even if set is full, but toggle the set_full flag to report -ENFILE so the abort path safely unwinds the set to its previous state. As for element updates, decrement set->nelems to restore it. A simpler fix is to call synchronize_rcu() in the error path. However, with a large batch adding elements to already maxed-out set, this could cause noticeable slowdown of such batches. Fixes: 35d0ac9070ef ("netfilter: nf_tables: fix set->nelems counting with no NLM_F_EXCL") Reported-by: Inseo An Signed-off-by: Pablo Neira Ayuso Signed-off-by: Florian Westphal [ Minor conflict resolved. ] Signed-off-by: Li hongliang <1468888505@139.com> Signed-off-by: Sasha Levin --- net/netfilter/nf_tables_api.c | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index a0914a92e07dd..6fc88bf511092 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -6803,6 +6803,7 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set, struct nft_data_desc desc; enum nft_registers dreg; struct nft_trans *trans; + bool set_full = false; u64 timeout; u64 expiration; int err, i; @@ -7095,10 +7096,18 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set, if (err < 0) goto err_elem_free; + if (!(flags & NFT_SET_ELEM_CATCHALL)) { + unsigned int max = nft_set_maxsize(set), nelems; + + nelems = atomic_inc_return(&set->nelems); + if (nelems > max) + set_full = true; + } + trans = nft_trans_elem_alloc(ctx, NFT_MSG_NEWSETELEM, set); if (trans == NULL) { err = -ENOMEM; - goto err_elem_free; + goto err_set_size; } ext->genmask = nft_genmask_cur(ctx->net); @@ -7130,23 +7139,16 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set, goto err_element_clash; } - if (!(flags & NFT_SET_ELEM_CATCHALL)) { - unsigned int max = nft_set_maxsize(set); - - if (!atomic_add_unless(&set->nelems, 1, max)) { - err = -ENFILE; - goto err_set_full; - } - } - nft_trans_elem(trans) = elem; nft_trans_commit_list_add_tail(ctx->net, trans); - return 0; -err_set_full: - nft_setelem_remove(ctx->net, set, &elem); + return set_full ? -ENFILE : 0; + err_element_clash: kfree(trans); +err_set_size: + if (!(flags & NFT_SET_ELEM_CATCHALL)) + atomic_dec(&set->nelems); err_elem_free: nf_tables_set_elem_destroy(ctx, set, elem.priv); err_parse_data: -- 2.53.0