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 E577B3F4DF2; Mon, 20 Jul 2026 11:14:07 +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=1784546049; cv=none; b=cjF0eLqYUfbTqC7rpTNxoU5KcwbK701lUi4A1rM4YJ9nJzcyfoN3KAipdHqRVDmyr2IDR2yDyhszQwwniXJjcCviYHFR5LEA3tt5sCa2AQ2bPzRbP53COiwSwvjCNeWBrlZIz9GqgC0Z7fY5Y6ri+yGZNqm4736eyPNT3ebXMIU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784546049; c=relaxed/simple; bh=YI82VNNEo/LwgUIDuwttqbRtglLcASOGSIS8oEAYia4=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=S6t1bO1bhl9PHDCyHL8k3TQcgl/cOTGc3+Z7yqUY/WbyFFnk1cVnpqYY4pZ7tnqQRp/n7mYg8cinyqAodcaB2lYAqEtqTXCiAa2u9AVkDtjHaJYNWs26dJBMpia7w8khA2PLVLi06vwyv7rIiRbT3X6n2/gf4nHcy2OkiH2vjfg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 Received: by smtp.kernel.org (Postfix) with ESMTPSA id E10F71F00A3A; Mon, 20 Jul 2026 11:14:05 +0000 (UTC) From: colyli@fygo.io To: yukuai@fygo.io Cc: linux-raid@vger.kernel.org, linux-block@vger.kernel.org, Coly Li , stable@vger.kernel.org, Ramesh Adhikari Subject: [PATCH] md: do overflow check for sb->bblog_shift in super_1_load() Date: Mon, 20 Jul 2026 19:14:00 +0800 Message-ID: <20260720111400.2120834-1-colyli@fygo.io> X-Mailer: git-send-email 2.47.3 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Coly Li In super_1_load(), sb->bblog_shift is an __u8 type value loaded from on- disk superblock. It is used for badblocks API badblocks_set() by the following sequence, 1930 rdev->badblocks.shift = sb->bblog_shift; 1931 for (i = 0 ; i < (sectors << (9-3)) ; i++, bbp++) { 1932 u64 bb = le64_to_cpu(*bbp); 1933 int count = bb & (0x3ff); 1934 u64 sector = bb >> 10; 1935 sector <<= sb->bblog_shift; 1936 count <<= sb->bblog_shift; 1937 if (bb + 1 == 0) 1938 break; 1939 if (!badblocks_set(&rdev->badblocks, sector, count, 1)) 1940 return -EINVAL; 1941 } bb->bblog_shit is in range of 0-255, variable sector is 64bit width, for an invalid bb->bblog_shit, it is possible to make sector be overflowed by the following calculation, 1935 sector <<= sb->bblog_shift; Then in turn when call badblocks_set() at line 1939 with the invalid rdev->badblocks.shift set at line 1930, may result an overflow inside _badblocks_clear() in block/badblocks.c. Although there are many places to call badblocks APIs, the non-zero shift value is only used in super_1_load(), other places always use 0 as the shift value. Therefore it is unnecessary to do a general shift value overflow check inside badblock API, and just check here as the caller. This may avoid unnecessary check, make the badblocks API code more simple and elegant. Fixes: 2699b67223aca ("md: load/store badblock list from v1.x metadata") Fixes: 1726c77467833 ("badblocks: improve badblocks_set() for multiple ranges handling") Cc: stable@vger.kernel.org Cc: Ramesh Adhikari Signed-off-by: Coly Li --- drivers/md/md.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/md/md.c b/drivers/md/md.c index d1465bcd86c8..67f8edf4db36 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -1918,10 +1918,17 @@ static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_ bb_sector = (long long)offset; if (!sync_page_io(rdev, bb_sector, sectors << 9, rdev->bb_page, REQ_OP_READ, true)) return -EIO; bbp = (__le64 *)page_address(rdev->bb_page); + + /* check for badblocks api. */ + if (sb->bblog_shift >= BITS_PER_TYPE(sector_t)) { + pr_err("md: %pg: bogus bblog_shift %u for badblocks.\n", + rdev->bdev, sb->bblog_shift); + return -EINVAL; + } rdev->badblocks.shift = sb->bblog_shift; for (i = 0 ; i < (sectors << (9-3)) ; i++, bbp++) { u64 bb = le64_to_cpu(*bbp); int count = bb & (0x3ff); u64 sector = bb >> 10; -- 2.47.3