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 4EC7A253331; Thu, 3 Apr 2025 19:10:10 +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=1743707410; cv=none; b=tmCUWysbNqdvHZUAhGYMEoyeB8ZwCDEe9z9ewieYyA6dhmy0hwlLSJbNDPL2RAZD/QDqP4qWLs3crhh0NP2Y1bL0x+dYd3m3KHKjU3SOCGRULUf8kpkHO0PYdPxhEYwe28vOB3USBHupWFa5meSj79DGV7pAb8U8ek+w0+WQegE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743707410; c=relaxed/simple; bh=fK2ogpiXpRoYoMpAwWAjaO9nttY7dsX12awqv0nZ1XQ=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=HFRb06RAeOeKTkeHfdLa95tC/IXRDLVbsgC8Xhs8gsi1bIyoGNf64SxW3amFiTTACXCECYtAJUVhbms2BhuHEdzZzl6ww6WTfuInOmo2mq6ucz/YqLJNUAUubPeSmX631e3eNgbSjzpeueiSYiUxI/hUuPWuJSChEIpMX1zVRxM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MRrIXOoj; 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="MRrIXOoj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DAA63C4CEE3; Thu, 3 Apr 2025 19:10:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743707410; bh=fK2ogpiXpRoYoMpAwWAjaO9nttY7dsX12awqv0nZ1XQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MRrIXOojZD5ltBgUIz3oZlqyZ0A2yZkf7ExDbc/4rhaqt8B4O8krbqzMKCbVwSaXi V0mfY8etoCJNTphiZq1DWmV4m7Iyxn4tDtlaw0oaQm5AKAVC5/woTyW1g5qrHG+bIv Wo5xr51fwa5OJlVkNpWFV2uWYp9fvtmCPsqo8uMdpk8Gxri6xec35+UsMkbS6qKlrr 1Y510j6c+8Vq7rjH5uqi29cV8yBnptm+hUVykce9KbdnwkdiLhqNRzL/oXt+vqx2r3 Cf0RFwAdEmaNpu5v4+eFMOAn23wwMi5Ql5JoTXeNmvMSC3+kyHCnc7hULLzlLxW8Kl 5f43uOmxDdppg== 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, rbrasga@uci.edu, ghanshyam1898@gmail.com, aha310510@gmail.com, niharchaithanya@gmail.com, jfs-discussion@lists.sourceforge.net Subject: [PATCH AUTOSEL 5.10 02/15] fs/jfs: cast inactags to s64 to prevent potential overflow Date: Thu, 3 Apr 2025 15:09:49 -0400 Message-Id: <20250403191002.2678588-2-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250403191002.2678588-1-sashal@kernel.org> References: <20250403191002.2678588-1-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 5.10.235 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 ef220709c7f51..389dafd23d15e 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