smb: client: fix heap overflow in cifs_do_set_acl()
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 |
|---|---|
| dc1af4c4b4721abfa07b351063825acc7e69cc66 to before d96f3365ce61c5f39602955af43c8174548dee98 | affected |
| dc1af4c4b4721abfa07b351063825acc7e69cc66 to before 596b4062e6c75bdd85a7f2b7f2087a872dc420ac | affected |
| dc1af4c4b4721abfa07b351063825acc7e69cc66 to before 1dac61e2c29d1a71784604b48cf3b1234a65ec29 | affected |
Linux · Linux
Other versions: affected
| Version / range | Source status |
|---|---|
| 6.2 | affected |
| 0 to before 6.2 | 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:
smb: client: fix heap overflow in cifs_do_set_acl()
cifs_set_acl() validates ACL size using posix_acl_xattr_size():
4 + (count * 8) // 4-byte header + 8 bytes per ACE
cifs_do_set_acl() then calls posix_acl_to_cifs() to write the CIFS wire format into the same buffer:
6 + (count * 10) // 6-byte header + 10 bytes per ACE
An ACL that passes the xattr-based check in cifs_set_acl() can overflow the heap when posix_acl_to_cifs() writes the larger CIFS format.
Validate the CIFS format size against the remaining buffer space and USHRT_MAX before converting--data_count is __u16, so sizes above USHRT_MAX truncate the on-wire packet length, causing the server to apply a partial ACL. Replace MaxDataCount = 1000 with min(CIFSMaxBufSize, USHRT_MAX).