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 6AFE320D4E3; Tue, 12 Nov 2024 10:24:41 +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=1731407081; cv=none; b=JTkk5j9c7TuqfVFuToTDfYuOVYS+UBoznxUeMsPwozgLbp1tZS8qPkhDD8Kj2xKq42UsU3AlB0o9RD8Xg6YS5SPlmXdtUZAHKEaT3gKRHSdDY6hB/6ZxU8yRE0gvFsFRsJm1zMa+bL5EdgquMi7UNG8vX7bz75DEug2Dc162s9g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731407081; c=relaxed/simple; bh=X1Z1IEkHUbY+bKF4prBAG4ymXFPCHkru0dO4UtN/Y2U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Neog024OpS9/cJzxkWyfvfN8jpJ0jSOm0wzaI3/kfC0YVdS4WsLqrIbzsQYfeig2AxNouK7Oig2xJmh64+urirnmenZ+BE0zFzmqU9dq95NKz8cewYIoE1rGqE1Hy61W+goSP1Vlh60Oq/zM1DKUYGXbno2bOk7kSpmNmpnS2jw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=La4SAII1; 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="La4SAII1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CF8B7C4CECD; Tue, 12 Nov 2024 10:24:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1731407081; bh=X1Z1IEkHUbY+bKF4prBAG4ymXFPCHkru0dO4UtN/Y2U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=La4SAII1rvcf1QqP8AzDmKFw70eXcnwNR1YMDL9uHxZIwOtQAS5hCaFow0mxYJARU LpGeQs0iwkD7GLmCsONZVX30SglP9Ziw3BxvYWN7hTHWoglAsGwEcJpId+Wy6kC84I Ui5W/5hxXzJb2RBZ5IIKK3lVxsVWDA9bnbZV2ABg= 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 5.15 44/76] dm cache: fix out-of-bounds access to the dirty bitset when resizing Date: Tue, 12 Nov 2024 11:21:09 +0100 Message-ID: <20241112101841.461553592@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241112101839.777512218@linuxfoundation.org> References: <20241112101839.777512218@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: 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 @@ -2891,13 +2891,13 @@ 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;