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 3D0E218734F; Fri, 15 Nov 2024 06:40:11 +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=1731652811; cv=none; b=DgkRDS4v0AIzVyFG6323uB7QLUDs/FyFJA9enfsPok5Ru4/hl9aoxUP5s8xdqVGYL0EpsOCzj55LX09bt7XXcttWJHrc883qrb/UQoty2PusYLDgaYQuhpnZ9tDmjGjyW0twGqhOQJeVxrfiBETAqh53kDhxnLgqMOLdKYyXqEo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731652811; c=relaxed/simple; bh=PSIRR2sKKiNXpAq0mC6Z8MeG/YFu8lp/wqRAZVUAgdM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=D6dcoeCqkkWL7s8ptgRIgViskqj9K03N+drscBBhIzJWqefoJkVz2nY1FhgbCrS79ADrd+1LYV9rThRG6SlFmFEboRO6P0VDqZ70xUszHX4pNSchtM5eTVsSuB+wexLO4Qd+Hkaiu1KawN3r3n1J/8w+fA3XM/WQVhGumYfqL4o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Vj1HO1wr; 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="Vj1HO1wr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AEB68C4CED9; Fri, 15 Nov 2024 06:40:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1731652811; bh=PSIRR2sKKiNXpAq0mC6Z8MeG/YFu8lp/wqRAZVUAgdM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Vj1HO1wry2BTPQUDgiYgkDf551NvNVzLU08ESTPEgpEsF/0V76/mGCElzF34uAUF3 xdv29POq73AaNoqNigXJJRxy57pqPNsmr877L4qTydhlnpBm/mT79BCSGpe98T1pDF l+2Mz27znm9DF+ubzPNQcar/PirTsEFQDC/NIvh4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ming-Hung Tsai , Mikulas Patocka , Joe Thornber Subject: [PATCH 4.19 21/52] dm cache: fix out-of-bounds access to the dirty bitset when resizing Date: Fri, 15 Nov 2024 07:37:34 +0100 Message-ID: <20241115063723.621903114@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241115063722.845867306@linuxfoundation.org> References: <20241115063722.845867306@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 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ming-Hung Tsai commit 792227719725497ce10a8039803bec13f89f8910 upstream. dm-cache checks the dirty bits of the cache blocks to be dropped when shrinking the fast device, but an index bug in bitset iteration causes out-of-bounds access. Reproduce steps: 1. create a cache device of 1024 cache blocks (128 bytes dirty bitset) dmsetup create cmeta --table "0 8192 linear /dev/sdc 0" dmsetup create cdata --table "0 131072 linear /dev/sdc 8192" dmsetup create corig --table "0 524288 linear /dev/sdc 262144" dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct dmsetup create cache --table "0 524288 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" 2. shrink the fast device to 512 cache blocks, triggering out-of-bounds access to the dirty bitset (offset 0x80) dmsetup suspend cache dmsetup reload cdata --table "0 65536 linear /dev/sdc 8192" dmsetup resume cdata dmsetup resume cache KASAN reports: BUG: KASAN: vmalloc-out-of-bounds in cache_preresume+0x269/0x7b0 Read of size 8 at addr ffffc900000f3080 by task dmsetup/131 (...snip...) The buggy address belongs to the virtual mapping at [ffffc900000f3000, ffffc900000f5000) created by: cache_ctr+0x176a/0x35f0 (...snip...) Memory state around the buggy address: ffffc900000f2f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc900000f3000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffffc900000f3080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ^ ffffc900000f3100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc900000f3180: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 Fix by making the index post-incremented. Signed-off-by: Ming-Hung Tsai Fixes: f494a9c6b1b6 ("dm cache: cache shrinking support") Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka Acked-by: Joe Thornber Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-cache-target.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -3002,13 +3002,13 @@ static bool can_resize(struct cache *cac * We can't drop a dirty block when shrinking the cache. */ while (from_cblock(new_size) < from_cblock(cache->cache_size)) { - new_size = to_cblock(from_cblock(new_size) + 1); if (is_dirty(cache, new_size)) { DMERR("%s: unable to shrink cache; cache block %llu is dirty", cache_device_name(cache), (unsigned long long) from_cblock(new_size)); return false; } + new_size = to_cblock(from_cblock(new_size) + 1); } return true;