From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792774995; b=3weQsJQkbCJfZb3S4gz2HZ2g+x7KqC1vaKVlkkPFEQktytkYIrCL+fejxWpgAG0tajaE sm7Z5xlYVEq9IRBmvJRlue8FNqg+kP5MG3xsifdMdD9wbUPRWZjWhH2BYSkdtHMlJhMjL HNYJ3oqfTFGdAay1JYVWlskZSbk8wtxFKC+rMGY+Hgsldl8lmIqac7hF8Or2mg+EaFKAG CsXCfkhBB91t1H25P3ON6Ge72Fke7yCXAgVdKkcDhcC2YxOg0/ADZU62q3UoRaJcD9z7J cvquziPxd/01/GkVS14swAQP3bMn5XPEElaHu3jvKZm2GfHocKhPa3RMYzkKIo7T1kg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792774995; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=Pu5zSZdttZJSgXmUMy0vkx+5EJ3fEPN5qXydSYm2lbg=; b=Op9g8R9g+ti41J4T2urhwrZCjfdLvxc/KcywhW/i7GKAW6+42qJnniUbt7iak62A8CYS p6krTi4KG+gmppUzLAJw7rVsX8dJtrflTlIrPFaJrsn65r2jGbGiFaSVu9LWEVfHbCyxd ucmRKvUVLSqmL9hDXBssJO6zNc7k3aG4jzPqYfD4Qgj9wnP6dqgrv5lMp+KDmzJUxOAcg lNXab0t7soenouUcgV18WArXvnkpM2MQPz3aeM364F1xBHJ9J9ZwfD+vFA4lbAx2xFWEf Xva0HdJxZWTEw3Wbx4Wzd3iFP0/DDUOatmO6ta1xYl2lFuMJUc0hZBjO+9/Twy+uGpg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=n8SzfGu7; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 71862606A31B; Fri, 23 Oct 2026 17:03:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=n8SzfGu7 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 596881F01825; Fri, 23 Oct 2026 17:03:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792774995; bh=Pu5zSZdttZJSgXmUMy0vkx+5EJ3fEPN5qXydSYm2lbg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=n8SzfGu7FgXH5C9Jm9Klb4Ly05meHc5jxVdzUknuxAXHeT6HqMYaxK9TrIMkrGFDe O04crcQLpsOu1Ysl8upxTzW1wJiQQ5bsSz3q3BpWi5BBSDjUgiaGdI8O75EasTU4uj 6IVi4yguNjSIPoft3onamqhEVhj9PUx42OMIPADg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Hongling Zeng , Baolin Liu , Namjae Jeon Subject: [PATCH 7.2 227/242] ntfs: fix undefined behavior in mft/index record size calculation Date: Fri, 23 Oct 2026 18:41:09 +0200 Message-ID: <20261023163719.210331003@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261023163713.816071858@linuxfoundation.org> References: <20261023163713.816071858@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hongling Zeng commit a79899ca38af4ce5518a59a22f0eb1f59f7e6089 upstream. The boot sector validation allows clusters_per_mft_record and clusters_per_index_record to range from 0xE1 (-31) to 0xF7 (-9) when interpreted as signed values. When these are used as negative shift counts in expressions like `1 << -clusters_per_mft_record`, values like 0xE1 cause `1 << 31`, which shifts into the sign bit of a 32-bit signed integer, resulting in undefined behavior. Fix by using unsigned shift (1U << ...) instead of signed shift. This prevents undefined behavior while preserving the full valid range of negative values (-31 to -9) that may appear in NTFS boot sectors. The encoding scheme uses negative values to represent record sizes smaller than cluster_size: -log2(record_size). Common values include -10 (1024 bytes) for mft_record_size and -12 (4096 bytes) for index_record_size. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Hongling Zeng Reviewed-by: Baolin Liu Signed-off-by: Namjae Jeon Signed-off-by: Greg Kroah-Hartman --- fs/ntfs/super.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/fs/ntfs/super.c +++ b/fs/ntfs/super.c @@ -695,7 +695,7 @@ static bool parse_ntfs_boot_sector(struc * = -log2(mft_record_size) bytes. mft_record_size normaly is * 1024 bytes, which is encoded as 0xF6 (-10 in decimal). */ - vol->mft_record_size = 1 << -clusters_per_mft_record; + vol->mft_record_size = 1U << -clusters_per_mft_record; vol->mft_record_size_mask = vol->mft_record_size - 1; vol->mft_record_size_bits = ffs(vol->mft_record_size) - 1; ntfs_debug("vol->mft_record_size = %i (0x%x)", vol->mft_record_size, @@ -732,7 +732,7 @@ static bool parse_ntfs_boot_sector(struc * index_record_size normaly equals 4096 bytes, which is * encoded as 0xF4 (-12 in decimal). */ - vol->index_record_size = 1 << -clusters_per_index_record; + vol->index_record_size = 1U << -clusters_per_index_record; vol->index_record_size_mask = vol->index_record_size - 1; vol->index_record_size_bits = ffs(vol->index_record_size) - 1; ntfs_debug("vol->index_record_size = %i (0x%x)",