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 719EA585970 for ; Fri, 11 Sep 2026 19:57:42 +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=1789156680; cv=none; b=Wit+1T8XWuPIWDDrRrj/nn5I7W9edlfi9dlmpsg8UxmcJgYLCsMK5q+lwXM46tmCSxEvxC/KNQpeoi8DRtuimLQvq8JIL/EpvR1f/GiM5W8wVuRLIuSjqW3teco1AyxHqsImmK4pYq0Ic23lePD+84cyYqKRmurFSuuA5SPTl6s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156680; c=relaxed/simple; bh=XqHqFN1JgmmKV8ybiFCqsCZBC1KMXcvOZYWNomP1cAA=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=jakQ2BpwzPKUWRdI4rCmn2Zhz6NldVrPf2Df34L39XBlUZsjZguRAcWJ65uecRDD++IuftFjOAWShBXrB3q8gHSaWDZRDA4WR2TiYWHUS+JmTuYR7y2g2Au93FI8zqquhqAEsr+E8ej5Hae4pQbCKPwT3QnsNeyyqdE6Xxu/8SA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Z6xz2gK1; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Z6xz2gK1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5D8111F0089C; Fri, 11 Sep 2026 19:57:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156661; bh=jwvszn4NbbLzphGWM29NOyk16HDFFRTf35/33RADDfk=; h=From:To:Cc:Subject:Date:Reply-To; b=Z6xz2gK1Auu1TjuLI6vyoc+S5jw0f2ShZL/RK9HZqGePNeuYRtv8eIDksYzO10Fh8 4FCEscOuIFKUWCnTRKNcIhM4OacqO4SFScorGdrsCWIfRheVgKqgrSQPU7V0w/QoBy dMXk8k9dwoOgHT87cjBYjCaP+SmOrcf55f8i4kGk= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89557: md: do overflow check for sb->bblog_shift in super_1_load() Date: Fri, 11 Sep 2026 21:44:06 +0200 Message-ID: <2026091123-CVE-2026-89557-55de@gregkh> X-Mailer: git-send-email 2.55.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3688; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=LQSXPXicihznopRE51wsiFTTEUIxlgkH9wV23sg9A18=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIpN/P5Tavqc2SM6z5fis8o8W81gvCbnf3PX29lbxS 9zT5rG0dcSyMAgyMciKKbJ82cZzdH/FIUUvQ9vTMHNYmUCGMHBxCsBE3KYxLJg5Le3Jh6m373Dw Kof9ldguonvF4TrDgh06P+YfN/VxXenm2Zp5Zl3tpl0zswE= X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In the Linux kernel, the following vulnerability has been resolved: md: do overflow check for sb->bblog_shift in super_1_load() 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. The Linux kernel CVE team has assigned CVE-2026-89557 to this issue. Affected and fixed versions =========================== Issue introduced in 3.1 with commit 2699b67223aca6b1450fc2f72e40fada952afc85 and fixed in 6.12.109 with commit 75d15738fd33a782606d0dc80cfeff47edf2ddd8 Issue introduced in 3.1 with commit 2699b67223aca6b1450fc2f72e40fada952afc85 and fixed in 6.18.50 with commit 3b097416b4cff77285c1f472fc2c4058d8a7554f Issue introduced in 3.1 with commit 2699b67223aca6b1450fc2f72e40fada952afc85 and fixed in 7.2.4 with commit df7d4d011d5ace20699ea948712f09f9ac08924f Issue introduced in 3.1 with commit 2699b67223aca6b1450fc2f72e40fada952afc85 and fixed in 7.3-rc1 with commit 35d522bd32462afcf1981dab6da8a9256c26c1e0 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2026-89557 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: drivers/md/md.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/75d15738fd33a782606d0dc80cfeff47edf2ddd8 https://git.kernel.org/stable/c/3b097416b4cff77285c1f472fc2c4058d8a7554f https://git.kernel.org/stable/c/df7d4d011d5ace20699ea948712f09f9ac08924f https://git.kernel.org/stable/c/35d522bd32462afcf1981dab6da8a9256c26c1e0