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 A74F7189902; Fri, 15 Nov 2024 06:40:17 +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=1731652817; cv=none; b=sDhHyUEjJEe5lKuEI1H/XEgLdayRz54W87acASQXRxo1dBMmtBHP+ycrtl5FIo53dTxfGhMZ8ZtY3XmTB8OjOOz46a+W9vC+9UNAS7NKg9OaksACbTPLNgDq749pVm8HG3iYdWDPIGKYy8DvKSxrlpjhNEQhLyxzUWvrqYF81rI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731652817; c=relaxed/simple; bh=Ns0sYMhu886R4S9qyyImfXSjkNtTb/vcAzHoniSNDIY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=S7Kriae00PNcv5xJesbvkZmDGhyM+LweAqhDvuUYQOlII0EOfAHcLCSHbsz/+FpZTcEWbgDbBgiTug48J36FxGxNsZh4rBFGMOJ1qv6YKrzNnfuBrex805Ocd29mSRGcfoA6K8A/lstTiYgotzmkqztjlVBoLmYbK18g6uxJWQY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=zolmkig2; 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="zolmkig2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 172ACC4CECF; Fri, 15 Nov 2024 06:40:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1731652817; bh=Ns0sYMhu886R4S9qyyImfXSjkNtTb/vcAzHoniSNDIY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zolmkig20dcju1nsvk87hB/LrYqUWti9TR43sx6e91ZPLVvYh/vO6z7fp7Tox0qr3 YLL7/qjKF4s35y2oRAqy6egVH+OPDOcaZ9XDUL7TEBzF5zLFqHK+n2ZBx2vKFuWxPE +LN6wDf/u7XFtcj7XVXbLRkr2LL+GXAPYX84rXmU= 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 23/52] dm cache: fix potential out-of-bounds access on the first resume Date: Fri, 15 Nov 2024 07:37:36 +0100 Message-ID: <20241115063723.694049653@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 c0ade5d98979585d4f5a93e4514c2e9a65afa08d upstream. Out-of-bounds access occurs if the fast device is expanded unexpectedly before the first-time resume of the cache table. This happens because expanding the fast device requires reloading the cache table for cache_create to allocate new in-core data structures that fit the new size, and the check in cache_preresume is not performed during the first resume, leading to the issue. Reproduce steps: 1. prepare component devices: dmsetup create cmeta --table "0 8192 linear /dev/sdc 0" dmsetup create cdata --table "0 65536 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 2. load a cache table of 512 cache blocks, and deliberately expand the fast device before resuming the cache, making the in-core data structures inadequate. dmsetup create cache --notable dmsetup reload cache --table "0 524288 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" dmsetup reload cdata --table "0 131072 linear /dev/sdc 8192" dmsetup resume cdata dmsetup resume cache 3. suspend the cache to write out the in-core dirty bitset and hint array, leading to out-of-bounds access to the dirty bitset at offset 0x40: dmsetup suspend cache KASAN reports: BUG: KASAN: vmalloc-out-of-bounds in is_dirty_callback+0x2b/0x80 Read of size 8 at addr ffffc90000085040 by task dmsetup/90 (...snip...) The buggy address belongs to the virtual mapping at [ffffc90000085000, ffffc90000087000) created by: cache_ctr+0x176a/0x35f0 (...snip...) Memory state around the buggy address: ffffc90000084f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc90000084f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 >ffffc90000085000: 00 00 00 00 00 00 00 00 f8 f8 f8 f8 f8 f8 f8 f8 ^ ffffc90000085080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc90000085100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 Fix by checking the size change on the first resume. 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 | 37 ++++++++++++++++--------------------- 1 file changed, 16 insertions(+), 21 deletions(-) --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -2991,24 +2991,24 @@ static dm_cblock_t get_cache_dev_size(st static bool can_resize(struct cache *cache, dm_cblock_t new_size) { if (from_cblock(new_size) > from_cblock(cache->cache_size)) { - if (cache->sized) { - DMERR("%s: unable to extend cache due to missing cache table reload", - cache_device_name(cache)); - return false; - } + DMERR("%s: unable to extend cache due to missing cache table reload", + cache_device_name(cache)); + return false; } /* * We can't drop a dirty block when shrinking the cache. */ - new_size = to_cblock(find_next_bit(cache->dirty_bitset, - from_cblock(cache->cache_size), - from_cblock(new_size))); - if (new_size != cache->cache_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; + if (cache->loaded_mappings) { + new_size = to_cblock(find_next_bit(cache->dirty_bitset, + from_cblock(cache->cache_size), + from_cblock(new_size))); + if (new_size != cache->cache_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; + } } return true; @@ -3039,20 +3039,15 @@ static int cache_preresume(struct dm_tar /* * Check to see if the cache has resized. */ - if (!cache->sized) { - r = resize_cache_dev(cache, csize); - if (r) - return r; - - cache->sized = true; - - } else if (csize != cache->cache_size) { + if (!cache->sized || csize != cache->cache_size) { if (!can_resize(cache, csize)) return -EINVAL; r = resize_cache_dev(cache, csize); if (r) return r; + + cache->sized = true; } if (!cache->loaded_mappings) {