From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 0012E28A3EE; Thu, 3 Apr 2025 19:10:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743707445; cv=none; b=nZIOE8/nE3kSsKeNVevry6Wo36j9lg4PMeR6UwUtSBsySp2Q3qSreDl8tBG7jLYnsvIfbc7Mwx0W4yNmTRtA44/LP8FUzMRjaqOGxYDsQnD3eAQq/d+4rjGxNNN7ufYyKz2Q9jH5DdbLMPHNjro3ElphNL/66tuLanEbH7wwi+g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743707445; c=relaxed/simple; bh=eBQc9PCYZrCjyx8p39U2MG6elWbeNnZFG9NajQGLrjc=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=OfU1okL5+Ius9PxLkYgroYLV7c42twmEalRCm/EQMt+VtNGqmjmjDQ3k7VCUTVjbwdUAq4z2c6SBpynHr39dv+HejYT5bBG3pZORM1ShCXk/An7hIoR1Q9m3adQoD1OD5yT7sLWrPbKmXsuzrSxJuTtCPs5j04z+5gi+Ht4ZXl0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XijhNIfY; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XijhNIfY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 19A7EC4CEE8; Thu, 3 Apr 2025 19:10:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743707444; bh=eBQc9PCYZrCjyx8p39U2MG6elWbeNnZFG9NajQGLrjc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XijhNIfYdzuW6H8O87CofRR7amBg71WtLFsjFPVu9nHDHXi5puPCw/qsiUp1Ei7FK T4s2qpREUBd7BKoDCLWejhmlFvfwXrVE1c/jCNmqF9SrV5hx2jUdjuVlC/ZMCAqgje zEBYiPmosxtExwfJeD45g/tK9EK6vkD13A79ux5uFYHk6rqof3BvLKUGU1Y35IQHnt sdaNg+iSBvShyKBioB62xmuZR4Luvkihc/dymfRdOZ+rpNmbnG/qx0oBOixYOl4Rc8 cde+WxbOuTWgHIhAF1wQuNHO8tULFv+vsSRzhQWOe/6nP4D9Vqwpf5uozkr18LKK96 lUQsM24vCxxQA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Rand Deeb , Dave Kleikamp , Sasha Levin , shaggy@kernel.org, eadavis@qq.com, niharchaithanya@gmail.com, rbrasga@uci.edu, aha310510@gmail.com, peili.dev@gmail.com, ghanshyam1898@gmail.com, jfs-discussion@lists.sourceforge.net Subject: [PATCH AUTOSEL 5.4 02/14] fs/jfs: cast inactags to s64 to prevent potential overflow Date: Thu, 3 Apr 2025 15:10:24 -0400 Message-Id: <20250403191036.2678799-2-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250403191036.2678799-1-sashal@kernel.org> References: <20250403191036.2678799-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.4.291 Content-Transfer-Encoding: 8bit From: Rand Deeb [ Upstream commit 70ca3246ad201b53a9f09380b3f29d8bac320383 ] The expression "inactags << bmp->db_agl2size" in the function dbFinalizeBmap() is computed using int operands. Although the values (inactags and db_agl2size) are derived from filesystem parameters and are usually small, there is a theoretical risk that the shift could overflow a 32-bit int if extreme values occur. According to the C standard, shifting a signed 32-bit int can lead to undefined behavior if the result exceeds its range. In our case, an overflow could miscalculate free blocks, potentially leading to erroneous filesystem accounting. To ensure the arithmetic is performed in 64-bit space, we cast "inactags" to s64 before shifting. This defensive fix prevents any risk of overflow and complies with kernel coding best practices. Found by Linux Verification Center (linuxtesting.org) with SVACE. Signed-off-by: Rand Deeb Signed-off-by: Dave Kleikamp Signed-off-by: Sasha Levin --- fs/jfs/jfs_dmap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c index 812945c8e3840..3bc304d4886e6 100644 --- a/fs/jfs/jfs_dmap.c +++ b/fs/jfs/jfs_dmap.c @@ -3728,8 +3728,8 @@ void dbFinalizeBmap(struct inode *ipbmap) * system size is not a multiple of the group size). */ inactfree = (inactags && ag_rem) ? - ((inactags - 1) << bmp->db_agl2size) + ag_rem - : inactags << bmp->db_agl2size; + (((s64)inactags - 1) << bmp->db_agl2size) + ag_rem + : ((s64)inactags << bmp->db_agl2size); /* determine how many free blocks are in the active * allocation groups plus the average number of free blocks -- 2.39.5