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 5C56343F4C3; Tue, 21 Jul 2026 22:21:58 +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=1784672520; cv=none; b=IJ6s0V4g2cd1LA4LVBxsRoRiIZf2lMgcZR5gsfZupuCPP2SSxqSwrt+VdAXfL1pWmnT2FCmW1HMOUkoPpQEWYa/VttGNouILEke3DkV3OxduQPBI/pioppB1HJWOAX5403IxtfZkdmAHJG/jfEmSHheizIZp7EEoWoT2F4y9mzY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784672520; c=relaxed/simple; bh=FXzeCFnFJbI19piZtLBertp05PBhh6mg07Vtq7qMRQg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=czhyz8t16+zFtMb2HqA5pfAHTQzmMscOdbAfZMWcPrUA557cR32EoSZKeg1NnlTpU1QLMG4t8jzX1WLJBzrGiLtwog2clrLWy+ScXzsrmoy3S6qpj48RpKYL7yKMMV3fDX32c2GT5MSl6eDzoMCWUyGc2uXRvXDF14QpKN3Pfsg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=xO/5+yQg; 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="xO/5+yQg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C174B1F000E9; Tue, 21 Jul 2026 22:21:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784672518; bh=bGIgKvVuLzgepPhkX2xQZGl1ee2gji+xUWVIxK/kGdY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=xO/5+yQgRPcubhhzSUoj1uBSGyHPAYHuJT/gGip+Dc58R3etAI/9RiulGyWUMnU3C VPm9O2My1lx18rBBsX5SY7EyZZuUmUk6Au6a/6wzm11WrYEUeIIYXZQsk4ECY5s6nz e7k685mtLoIJ86q8/UEKoDYDBZumB5/GzrY4yq3A= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Benjamin Marzinski , Mikulas Patocka Subject: [PATCH 5.15 655/843] dm-log: fix a bitset_size overflow on 32bit machines Date: Tue, 21 Jul 2026 17:24:50 +0200 Message-ID: <20260721152420.802896515@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152405.946368001@linuxfoundation.org> References: <20260721152405.946368001@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Benjamin Marzinski commit 9743132a41f4d9d0e54c5f2adcb821b04796bab1 upstream. Commit c20e36b7631d ("dm log: fix out-of-bounds write due to region_count overflow") made sure that region_count could fit in an unsigned int. But the bitmap memory isn't allocated based on region_count. It uses bitset_size (a size_t variable). The first step of calculating bitset_size is to set it to region_count, rounded up to a multiple of BITS_PER_LONG. If region_size is less than BITS_PER_LONG smaller than UINT_MAX, it will get rounded up to 2^32. On a 32bit architecture, this will make bitset_size wrap around to 0 and fail, despite region_count being valid. Since bitset_size gets divided by 8, it can hold any valid region_count. It just needs a special case to handle the rollover. If it is 0, the value rolled over, and bitset size should be set to the number of bytes needed to hold 2^32 bits. Signed-off-by: Benjamin Marzinski Signed-off-by: Mikulas Patocka Fixes: c20e36b7631d ("dm log: fix out-of-bounds write due to region_count overflow") Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-log.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/md/dm-log.c +++ b/drivers/md/dm-log.c @@ -421,6 +421,9 @@ static int create_log_context(struct dm_ */ bitset_size = dm_round_up(region_count, BITS_PER_LONG); bitset_size >>= BYTE_SHIFT; + /* Handle dm_round_up rollover on 32-bit systems */ + if (!bitset_size) + bitset_size = 1UL << (BITS_PER_LONG - BYTE_SHIFT); lc->bitset_uint32_count = bitset_size / sizeof(*lc->clean_bits);