6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Frank Sorenson <redacted>
commit 6c322f5cf7476ded7a9a20f7be72462065a03c68 upstream.
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: <redacted>
Signed-off-by: Frank Sorenson <redacted>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/smb/client/cifsfs.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
--- a/fs/smb/client/cifsfs.c
+++ b/fs/smb/client/cifsfs.c
@@ -1317,8 +1317,19 @@ static loff_t cifs_remap_file_range(stru
*/
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, "clone range\n");