From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-129.mta1.migadu.com [95.215.58.129]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6621936B928 for ; Sun, 23 Aug 2026 15:11:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.129 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787497896; cv=none; b=Xcvpg3Rt/yA50ERRTL0WEF/GG6VbYgYv/CN9qMAhc3QfbmNW4tmnF3yTJRbITzT43gFcYG0OALwfGJv0vfkGB399+rjikCwla4JP7DG0uH8/IdpBGG+wwLHsnV6LbWdQXGCqCBSY0luypt8RYxKpucJkkoAVyaW/IYR6MaHAufk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787497896; c=relaxed/simple; bh=wLD20CgWJXIysPLhdyNyOF51BfWz7KZURSsyYC0vNes=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=lPa3ri3yaefJN6rop9Ml6VPn0MEXgfwInVM2uAFFcerArtT+KN7WQDdmGT00TnD6lFbN+LOJKBvPFFGaBbGpq7ic1EtQjldV13/oPWHURpeNBTQYI95PesMCVT7nq/VnpgivoAgdKDKuW7ScvsuQSAfY9n1fPmX5KXrNYGQWmtA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=mRthk1HX; arc=none smtp.client-ip=95.215.58.129 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="mRthk1HX" X-Envelope-To: linux-cifs@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=wLD20CgWJXIysPLhdyNyOF51BfWz7KZURSsyYC0vNes=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1787497891; v=1; x=1788102691; b=mRthk1HXiMW+0/9sJjtp631TYe/h0Ex41/7/ibcasUD2WCLBUHCvvJbOaCgxgb+ev9l382LT E1F1xshBL2MDI50zTRRsuThgainJcqxcn3eF7mnDHDEOTpP8s7GMeMPP63QOF/SKVfE6piQI6ju dJDfP70s4kkGQWwQa9SNEfkM= X-Envelope-To: linux-cifs@vger.kernel.org Received: from localhost.localdomain (2408:8352:470:269e:918b:d2e0:eaa5:de79) by smtp.migadu.com with ESMTPS id 309e12369837ce1a; Sun, 23 Aug 2026 15:11:31 +0000 X-Mizu-Trace-ID: 309e12369837ce1a X-Migadu-Flow: FLOW_OUT From: Huiwen He To: linkinjeon@kernel.org, pc@manguebit.org, ronniesahlberg@gmail.com, sprasad@microsoft.com, tom@talpey.com, bharathsm@microsoft.com, senozhatsky@chromium.org, dhowells@redhat.com, chenxiaosong@kylinos.cn Cc: linux-cifs@vger.kernel.org Subject: [PATCH v3 1/7] smb/client: validate new EOF for insert range Date: Sun, 23 Aug 2026 23:10:47 +0800 Message-ID: <20260823151053.935889-2-huiwen.he@linux.dev> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260823151053.935889-1-huiwen.he@linux.dev> References: <20260823151053.935889-1-huiwen.he@linux.dev> Precedence: bulk X-Mailing-List: linux-cifs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Huiwen He smb3_insert_range() does not check if the new file size (i_size + len) is valid. This allows FALLOC_FL_INSERT_RANGE to bypass RLIMIT_FSIZE, exceed s_maxbytes, or produce a size outside the loff_t range. Use check_add_overflow() to calculate the new EOF. Validate it with inode_newsize_ok() before modifying the file. Reproducer, using a file on a CIFS mount: bash -c ' FILE=/mnt/cifs/repro trap "" SIGXFSZ ulimit -f 3072 # RLIMIT_FSIZE = 3 MiB # A regular write is stopped at 3 MiB. dd if=/dev/zero of="$FILE" bs=1M count=4 status=none stat -c "size after write: %s" "$FILE" # Insert 2 MiB into a 2 MiB file. truncate -s 2M "$FILE" fallocate -i -o 0 -l 2M "$FILE" stat -c "size after insert: %s" "$FILE" ' Before this change, the regular write stops at the 3 MiB limit, but insert range grows the file to 4 MiB: dd: error writing '/mnt/cifs/repro': File too large size after write: 3145728 size after insert: 4194304 After this change, insert range also fails at the limit and leaves the 2 MiB file unchanged: dd: error writing '/mnt/cifs/repro': File too large size after write: 3145728 fallocate: fallocate failed: File too large size after insert: 2097152 Fixes: 7fe6fe95b936 ("cifs: add FALLOC_FL_INSERT_RANGE support") Signed-off-by: Huiwen He Reviewed-by: ChenXiaoSong --- fs/smb/client/smb2ops.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c index 192649fec25d..bc7dda6d825a 100644 --- a/fs/smb/client/smb2ops.c +++ b/fs/smb/client/smb2ops.c @@ -3985,7 +3985,8 @@ static long smb3_insert_range(struct file *file, struct cifs_tcon *tcon, struct cifsFileInfo *cfile = file->private_data; struct inode *inode = file_inode(file); struct cifsInodeInfo *cifsi = CIFS_I(inode); - __u64 count, old_eof, new_eof; + u64 count; + loff_t old_eof, new_eof; xid = get_xid(); @@ -3995,8 +3996,15 @@ static long smb3_insert_range(struct file *file, struct cifs_tcon *tcon, goto out; } + if (check_add_overflow(old_eof, len, &new_eof)) { + rc = -EFBIG; + goto out; + } + rc = inode_newsize_ok(inode, new_eof); + if (rc) + goto out; + count = old_eof - off; - new_eof = old_eof + len; filemap_invalidate_lock(inode->i_mapping); rc = filemap_write_and_wait_range(inode->i_mapping, off, new_eof - 1); -- 2.43.0