From patchwork Tue Oct 22 07:13:54 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming-Hung Tsai X-Patchwork-Id: 13845230 X-Patchwork-Delegate: mpatocka@redhat.com Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 45BDA1494CE for ; Tue, 22 Oct 2024 07:14:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729581259; cv=none; b=gqJ6lgFVrPl04HoIC/yMv/Iwn3R6ptXLivvuN4ejTuD5BFKVUrc8MbgLDtlWwXOWrKhsZ2sJ+M6R11ANEa+NpnbVca/S+S8vjiHxnxjnUzQHx+liO7w4sJz08Y0YwV4T1Ytp2ivlb+pd2sj8Q4Lm9fjWclHzwAJMMGFJBGr2vV0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729581259; c=relaxed/simple; bh=Q8ENeAkz48Y3VTR3Dq4JyHQdC/MhcnnpEPGIlvpUPdo=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=azwEkC8b776rfSt6kmHd5WyAdJoxUwDDteBllgn/cY7JO/OSaYdPsH7SW2E29g1E7p7S/y3w2cmh8zZhi+GRDe7+OZtYtQmSXcF6vQt9qwJo/3+oabTmztVap6GhldF2lnpcTrf2HFir/LHvJdj0a/L2PWxqC2Q1lwM/0iXc8GI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=MfUzMQzi; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="MfUzMQzi" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1729581256; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=vyrm88n/l7VkCAM9KVpNUNAT+MCV4oTA4h4H35isFR4=; b=MfUzMQzizLrlhWpg0jum1N8MyjQEFON/TgiU7iBYoayCrhJ4CmUpbYvfYm4s/BM0ZhXkzx HEyYCRdA9j675u9HbbI+t+nyBo9+vUArvMcsZnXPqekCwEvM2WVxR5RcFlzw5YpszGRJLx VLQyIRNI9+tM40vkSXGwsafEyouIhEE= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-439-40kV8SuRNnuJM90TMW7E0A-1; Tue, 22 Oct 2024 03:14:12 -0400 X-MC-Unique: 40kV8SuRNnuJM90TMW7E0A-1 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 191FD19560A2; Tue, 22 Oct 2024 07:14:12 +0000 (UTC) Received: from thinkpad.redhat.com (unknown [10.67.24.92]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id AA69C1955F39; Tue, 22 Oct 2024 07:14:08 +0000 (UTC) From: Ming-Hung Tsai To: dm-devel@lists.linux.dev Cc: mpatocka@redhat.com, thornber@redhat.com, heinzm@redhat.com, snitzer@kernel.org, Ming-Hung Tsai Subject: [PATCH 5/5] dm cache: fix potential out-of-bounds access on the first resume Date: Tue, 22 Oct 2024 15:13:54 +0800 Message-ID: <20241022071354.778749-1-mtsai@redhat.com> Precedence: bulk X-Mailing-List: dm-devel@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com 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") --- drivers/md/dm-cache-target.c | 37 ++++++++++++++++-------------------- 1 file changed, 16 insertions(+), 21 deletions(-) diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c index fa8ef2c32af8..40709310e327 100644 --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -2901,24 +2901,24 @@ static dm_cblock_t get_cache_dev_size(struct cache *cache) 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; @@ -2949,20 +2949,15 @@ static int cache_preresume(struct dm_target *ti) /* * 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) {