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 53CD7286A4 for ; Mon, 7 Sep 2026 01:03:22 +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=1788743003; cv=none; b=M2PPYeKWHAJD20jJmJ49X5xUgOjyXbp4RVFUXuuJ/BOSO2cWBGIMJGZnX/zGY49nhCanzjR5tz8C1RS/nLWJ0rUQYZRB0gs3nMliuMq0mjV/SMTFb6pnCzjbuuXrTF+++EvU5I6LIPpXhaay+7cOLV+iXtCmW0XpLqT0+rnZkZw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788743003; c=relaxed/simple; bh=OVak9tL2byUvu8cSSyvrwsL3yhG+KmC3husRegqMfEo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OdySQzCB3Sc6cvl07QuGD0t4kkdZJA0VEPAYZNf/ejpyw5acZOCDg+DP82OxLkA2McBYLb4FrebgBVaXO34DGDPj2ii2IxYyO7PPLYYkoWFZE7QB4n8QnKaH9aj7oGw4mEeNdr16LDEtsvS9IVdCkvzGazujOobG/QgJ1BXKtlk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LP6bC+DI; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="LP6bC+DI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AAC171F00AC4; Mon, 7 Sep 2026 01:03:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788743002; bh=WaUeF5JCeZgK1wUNbhoMVmx0N4TVvOWfH9o/f4lv8vg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=LP6bC+DIEeho4JfNJXYmxZHGWwTMv4+WjaDCZokfMOt+x+v5UBOY68efNy+kgTgh9 zQ+Wi5yRP8vcCfEGBhIkVTX44Iwxi7Y/AHa4MmtjngdC0zC42bY+sQjgzlobVh5kVH ICSC2DVe117eyTLIrKWOxDxuiL8WrR3Mu9y999Z0FbFGv8P+Z9QpradFtBP5ILL+p7 Zh5oMsGIgBFM07qFHpqERgXcL0ux/zUImmY3GCwqD82vU/VrGJiogIudd5I2SZq8QY VmSCA0Zjx2w6dBDX/HnZBfRBJZ53NhRw2BwW8GvsM8K4zD6Ktb8GpGmfNRuQX4nb0u tvv/KD+bjq7fg== From: Sasha Levin To: stable@vger.kernel.org Cc: Frank Sorenson , Namjae Jeon , Paulo Alcantara , Sasha Levin Subject: [PATCH 5.10.y] cifs: fix loff_t underflow in cifs_remap_file_range() when len == 0 Date: Sun, 6 Sep 2026 21:03:19 -0400 Message-ID: <20260907010319.1950366-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026090322-dweeb-catchy-bac2@gregkh> References: <2026090322-dweeb-catchy-bac2@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Frank Sorenson [ Upstream commit 6c322f5cf7476ded7a9a20f7be72462065a03c68 ] With len == 0 (clone to EOF), the effective length is computed as: len = src_inode->i_size - off; If off > i_size, this is a negative loff_t, corrupting the ByteCount in the FSCTL_DUPLICATE_EXTENTS_TO_FILE request and inverting the range in filemap_write_and_wait_range(). The existing off >= i_size check fires only after the ioctl has already been sent. Snapshot i_size_read() once for both the bounds check and the length calculation, eliminating the TOCTOU and 32-bit torn-read risk. Reject off > src_size with -EINVAL. Treat off == src_size as a no-op, consistent with __generic_remap_file_range_prep(). Fixes: 04b38d601239 ("vfs: pull btrfs clone API to vfs layer") Cc: stable@vger.kernel.org Signed-off-by: Frank Sorenson Reviewed-by: Namjae Jeon Signed-off-by: Paulo Alcantara [ added the missing unlock label at the existing common unlock path ] Signed-off-by: Sasha Levin --- fs/cifs/cifsfs.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index 900ac4d04d901..228087c90de25 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -1117,8 +1117,19 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off, */ lock_two_nondirectories(target_inode, src_inode); - if (len == 0) - len = src_inode->i_size - off; + if (len == 0) { + loff_t src_size = i_size_read(src_inode); + + if (off > src_size) { + rc = -EINVAL; + goto unlock; + } + len = src_size - off; + if (!len) { + rc = 0; + goto unlock; + } + } cifs_dbg(FYI, "about to flush pages\n"); /* should we flush first and last page first */ @@ -1134,6 +1145,7 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off, /* force revalidate of size and timestamps of target file now that target is updated on the server */ CIFS_I(target_inode)->time = 0; +unlock: /* although unlocking in the reverse order from locking is not strictly necessary here it is a little cleaner to be consistent */ unlock_two_nondirectories(src_inode, target_inode); -- 2.53.0