From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 A17BA19AD51; Tue, 16 Jul 2024 16:07:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721146040; cv=none; b=bsNhglu2J0TEI5ALtNhYMhDzi5bltLW3nfn779l5k/O6ZYiw8DZOYf5wUsb7Vq3GC0ESEBwYl0ynfA3oG9Cq3Bt2uwoNGatosbAdB2bHLFr3rJJvmDMLo+oOR+0GIGZFITHh/gdJ3a9feooW04MH1R8eElnZmpEIzB5XQsupnIA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721146040; c=relaxed/simple; bh=+4CRm1bSxxWccrsUEYAq+xFLPS5GfXj4j9yhI6klYY8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RsVcAUt4AUGsEaMd1hNVQKtZZ2vpuJNJwrnG1X4WDlLPAfsja/muslWUSV7eA89CBGVXVzJAhhdFAMEV7HKeOWUM+zRkyw54tri7Gls0MFcPDE1QaDLwQMTn/i0ZlFXtNrfkvtEpmm5KT3WUzq5LkqO+3ADuglD0S6q8XECl1XY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=HS0kLm24; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="HS0kLm24" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D3427C116B1; Tue, 16 Jul 2024 16:07:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1721146040; bh=+4CRm1bSxxWccrsUEYAq+xFLPS5GfXj4j9yhI6klYY8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HS0kLm24EwN/NhGdzDFq9ujOobHtrbR/WK777ZLyq/Fz9XXBYuSzE31/2jpWdp7Nv aN5sXAakFk2TmbQaLPodFWMG4ZJQYcWv6wP4dhhnW5HjGowbUUF9rN3aPFJZKY6z88 Vs5OTH1tiKXGC8bb+AP9zHLElle1PaTg3b3Wo2+o= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Florian Westphal , Pablo Neira Ayuso , Sasha Levin , syzbot+4fd66a69358fc15ae2ad@syzkaller.appspotmail.com Subject: [PATCH 5.15 038/144] netfilter: nf_tables: unconditionally flush pending work before notifier Date: Tue, 16 Jul 2024 17:31:47 +0200 Message-ID: <20240716152754.008272586@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240716152752.524497140@linuxfoundation.org> References: <20240716152752.524497140@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Florian Westphal [ Upstream commit 9f6958ba2e902f9820c594869bd710ba74b7c4c0 ] syzbot reports: KASAN: slab-uaf in nft_ctx_update include/net/netfilter/nf_tables.h:1831 KASAN: slab-uaf in nft_commit_release net/netfilter/nf_tables_api.c:9530 KASAN: slab-uaf int nf_tables_trans_destroy_work+0x152b/0x1750 net/netfilter/nf_tables_api.c:9597 Read of size 2 at addr ffff88802b0051c4 by task kworker/1:1/45 [..] Workqueue: events nf_tables_trans_destroy_work Call Trace: nft_ctx_update include/net/netfilter/nf_tables.h:1831 [inline] nft_commit_release net/netfilter/nf_tables_api.c:9530 [inline] nf_tables_trans_destroy_work+0x152b/0x1750 net/netfilter/nf_tables_api.c:9597 Problem is that the notifier does a conditional flush, but its possible that the table-to-be-removed is still referenced by transactions being processed by the worker, so we need to flush unconditionally. We could make the flush_work depend on whether we found a table to delete in nf-next to avoid the flush for most cases. AFAICS this problem is only exposed in nf-next, with commit e169285f8c56 ("netfilter: nf_tables: do not store nft_ctx in transaction objects"), with this commit applied there is an unconditional fetch of table->family which is whats triggering the above splat. Fixes: 2c9f0293280e ("netfilter: nf_tables: flush pending destroy work before netlink notifier") Reported-and-tested-by: syzbot+4fd66a69358fc15ae2ad@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=4fd66a69358fc15ae2ad Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin --- net/netfilter/nf_tables_api.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 506dc5c4cdccb..6e4ce511f51ba 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -10659,8 +10659,7 @@ static int nft_rcv_nl_event(struct notifier_block *this, unsigned long event, gc_seq = nft_gc_seq_begin(nft_net); - if (!list_empty(&nf_tables_destroy_list)) - nf_tables_trans_destroy_flush_work(); + nf_tables_trans_destroy_flush_work(); again: list_for_each_entry(table, &nft_net->tables, list) { if (nft_table_has_owner(table) && -- 2.43.0