From patchwork Tue Oct 22 07:13:16 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: 13845228 X-Patchwork-Delegate: mpatocka@redhat.com Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 409BD148FE6 for ; Tue, 22 Oct 2024 07:13:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729581223; cv=none; b=owzCd7y4wbIErHWL3PXbjYlzZyY9hFvLm1uAjavDBC9Zx0b68ITj8EvMHsW3DAt9yZ38c44t5DnTkR2MF3cf8lfUK04H9F3/fGpwJMnb1GdSZIBQmXZg+8eq4AolYPz5KGaRjhiDnkFto0fYzwbx6UeZCnftIz56P1KeoGwbsXM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729581223; c=relaxed/simple; bh=HziE+9R9hbAULDhZfQfMVIYcLf8bwHGg5b/8sQ/CIsU=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=A+XHN7HWkhg2Daqek5y8IGZMerZfpXr1jluTucnytyhjHN/lQFZKYdJ1B6eRFXmCc3KTjlYr6zSFfdYaviGJBGX/UGZNwpc2aYIzA5NnHIl3f4bM5UgQGuKZT8Ht9RIYDdao62fL5N3p9DYnPYPBZNNuy8OLf2OcPdrg/wAhURY= 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=E2tLMpSm; arc=none smtp.client-ip=170.10.133.124 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="E2tLMpSm" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1729581221; 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=Cg8EzfYlEr6Qde/+EDpQcl/0vJfF0E9uTITWkJfKrUY=; b=E2tLMpSmgG0LbHvnOOlcxiy6SbxjP3WnzfVU/l+95llmFdG2MZ7Aoo9060KC/pschF+za3 oF+LV5lcS4xLPYcM9u4aS11BhaxCpA5nn5kSHn8qhcDUVHuo1FLYfPdK5hz4iKdGUCyBR0 7jTTRgyIMW/xke3sa2SmqN0h3WKlYiE= Received: from mx-prod-mc-02.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-220-lk8F_xQCOFKVmn16bTxPLw-1; Tue, 22 Oct 2024 03:13:40 -0400 X-MC-Unique: lk8F_xQCOFKVmn16bTxPLw-1 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (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-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1ECB51956096; Tue, 22 Oct 2024 07:13:39 +0000 (UTC) Received: from thinkpad.redhat.com (unknown [10.67.24.92]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9E2801955F43; Tue, 22 Oct 2024 07:13:35 +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 3/5] dm cache: fix out-of-bounds access to the dirty bitset when resizing Date: Tue, 22 Oct 2024 15:13:16 +0800 Message-ID: <20241022071316.778660-1-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 10.30.177.40 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com 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") --- drivers/md/dm-cache-target.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c index 68e9a1abd303..1fcd8c5c220e 100644 --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -2912,13 +2912,13 @@ static bool can_resize(struct cache *cache, dm_cblock_t new_size) * 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;