cifs: don't update i_size in cifs_do_truncate without a cached handle
Impact
In the Linux kernel, the following vulnerability has been resolved:
Source excerpt · LinuxAffected packages
Affected products
Vendor version evidence. Product records are separate from automatic dependency matching.
Linux · Linux
Other versions: unaffected
| Version / range | Source status |
|---|---|
| 110fee6b9bb58a5c50047fc2594d415f741b591e to before 04d020b3d0b58a1b7e116900e4095b96a7f4e11a | affected |
| 110fee6b9bb58a5c50047fc2594d415f741b591e to before 88a51743cd8094b76fd910f53f718747c7729cc8 | affected |
| 110fee6b9bb58a5c50047fc2594d415f741b591e to before fe39cd9d48f2346605f3746e0cc19e89d5f373eb | affected |
Linux · Linux
Other versions: affected
| Version / range | Source status |
|---|---|
| 6.18 | affected |
| 0 to before 6.18 | unaffected |
| 6.18.59 through 6.18.* (inclusive) | unaffected |
| 7.2.13 through 7.2.* (inclusive) | unaffected |
| 7.3 through * (inclusive) | unaffected |
Original source description
In the Linux kernel, the following vulnerability has been resolved:
cifs: don't update i_size in cifs_do_truncate without a cached handle
If find_writable_file() returns null, cifs_file_flush will return 0 without issuing set_file_size, and the outer 'if (!rc)' block will set i_size to 0 before telling the server to truncate. If the cifs_open() then fails, the inode will have size 0, while the server file is unchanged.
Move the netfs_resize_file() and cifs_setsize() into the 'if (cfile)', so they only run after a successful set_file_size.
In the no-handle else branch, evict stale pages with truncate_inode_pages before the O_TRUNC open to dispose of old cache pages, and let the open response set the i_size.