From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 8954254DAF4 for ; Tue, 8 Sep 2026 13:21:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788873715; cv=none; b=KxsMad1QJ3maZECeoZ3yPq7zMQtjxJOvoFqCPojkPrzHid10bw2GDNlHUMU80zPJkOi4e8dl/Md6WM1U2FTgwJvlDJEXKtCQ/oI8OwZoaUPb0YLvlG7AITnKrD6KtVeTq+thBtJetWmW6dJd0KHdV4Ch2zaj+yvVBGVtsGu02qY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788873715; c=relaxed/simple; bh=pgYO5F07vAjyjZZxywRAUgLDuqJN/Edeh3d2JntgReo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=dI2oBvl9Hh/gqc0Jb0DbvhsXVAj/PHTxT8KpyH6+D74KwPSPBrlBbp5ZBgLCTvngfqC8284qpY0OTxCLL9DVsYtPOHjxVdbjEmt52vnZljOTVBr6FSg3LjvLOcUrOGuvqHO/Qa8rLM57qsRsG9ocGKa6wEIsCmGW4u3NKt9j8bw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UFloy1DW; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UFloy1DW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A03AA1F00ACF; Tue, 8 Sep 2026 13:21:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788873713; bh=/wZDj9uebFbdMyVKBKkMzueDFreuZbiUheBuOChPTHw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=UFloy1DW50JLluJ8zs4bmQ2B9eSM/l7SoWDW7Kzb72TMQ8zt/8agvw001COJqq7ZX 4NL1umaGhJHhD8D3fbq5lLuKK4Y1oPkgOsLXKLDw2/MwsI/P1EjLY6OowKq/hW3brN WIfqCL60RBaGJVAAF8rAAlfaDrWJeFuqcYcvBuL35ayaztH3Al3xoqpflc7+3MRKk/ cUrad1upCUonspmKuc9uXTRC78TE3CsJ0CUPV2l5LBnBiwqidUk61oT70+VJMHKSwZ iYo32JAq7JibwPxgBSob0kW20mU2FXzXlcOZiIDhwlroD4eUjFxumGR7pCsnI0FkoY N5IqI0CCZ07OA== From: Sasha Levin To: stable@vger.kernel.org Cc: Bryam Vargas , Ming-Hung Tsai , Mikulas Patocka , Sasha Levin Subject: [PATCH 5.15.y] dm array: validate array block headers on read Date: Tue, 8 Sep 2026 09:21:50 -0400 Message-ID: <20260908132150.2288286-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026090304-header-ideally-ce6b@gregkh> References: <2026090304-header-ideally-ce6b@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Bryam Vargas [ Upstream commit 2965787723084835b18dfe993cd450ebf5bd4540 ] array_block_check() validates blocknr and csum and nothing else, while node_check(), next to it, has bounded the structural fields since both were written. dm_array_cursor_next() takes its loop bound from the on-disk nr_entries and element_at() is unguarded pointer arithmetic, so a count larger than the block holds keeps the cursor in one block while the index grows past it and the read walks off the dm-bufio buffer -- dm_cache_load_mappings() drives it once per cache block at activation. Check the header against itself: reject a zero value_size, require max_entries to equal calc_max_entries() for that value_size and block size, and require nr_entries to fit. Equality rather than an upper bound, since a count below the real capacity trips BUG_ON() in fill_ablock() and trim_ablock(). Metadata dm-array writes satisfies all three. Fixes: 6513c29f44f2 ("dm persistent data: add transactional array") Suggested-by: Ming-Hung Tsai Cc: stable@vger.kernel.org Signed-off-by: Bryam Vargas Reviewed-by: Ming-Hung Tsai Signed-off-by: Mikulas Patocka [ retained Linux 6.6’s non-const validator callback signature due to the missing constification commit. ] Signed-off-by: Sasha Levin --- drivers/md/persistent-data/dm-array.c | 37 +++++++++++++++++++++------ 1 file changed, 29 insertions(+), 8 deletions(-) diff --git a/drivers/md/persistent-data/dm-array.c b/drivers/md/persistent-data/dm-array.c index 1f1dd077d3f84..18f6bc0bbafa5 100644 --- a/drivers/md/persistent-data/dm-array.c +++ b/drivers/md/persistent-data/dm-array.c @@ -37,6 +37,14 @@ struct array_block { */ #define CSUM_XOR 595846735 +/* + * Each array block can hold this many values. + */ +static uint32_t calc_max_entries(size_t value_size, size_t size_of_block) +{ + return (size_of_block - sizeof(struct array_block)) / value_size; +} + static void array_block_prepare_for_write(struct dm_block_validator *v, struct dm_block *b, size_t size_of_block) @@ -54,6 +62,7 @@ static int array_block_check(struct dm_block_validator *v, size_t size_of_block) { struct array_block *bh_le = dm_block_data(b); + uint32_t nr_entries, max_entries, value_size; __le32 csum_disk; if (dm_block_location(b) != le64_to_cpu(bh_le->blocknr)) { @@ -73,6 +82,26 @@ static int array_block_check(struct dm_block_validator *v, return -EILSEQ; } + nr_entries = le32_to_cpu(bh_le->nr_entries); + max_entries = le32_to_cpu(bh_le->max_entries); + value_size = le32_to_cpu(bh_le->value_size); + + if (!value_size) { + DMERR_LIMIT("%s failed: value_size is zero", __func__); + return -EILSEQ; + } + + if (max_entries != calc_max_entries(value_size, size_of_block)) { + DMERR_LIMIT("%s failed: max_entries %u invalid for value_size %u", + __func__, max_entries, value_size); + return -EILSEQ; + } + + if (nr_entries > max_entries) { + DMERR_LIMIT("%s failed: too many entries", __func__); + return -EILSEQ; + } + return 0; } @@ -136,14 +165,6 @@ static void dec_ablock_entries(struct dm_array_info *info, struct array_block *a on_entries(info, ab, vt->dec); } -/* - * Each array block can hold this many values. - */ -static uint32_t calc_max_entries(size_t value_size, size_t size_of_block) -{ - return (size_of_block - sizeof(struct array_block)) / value_size; -} - /* * Allocate a new array block. The caller will need to unlock block. */ -- 2.53.0