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).

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).

Affected: Ubuntu:16.04:LTS: linux-hwe-edge, Ubuntu:18.04:LTS: linux-aws-5.0, Ubuntu:18.04:LTS: linux-aws-5.3, Ubuntu:18.04:LTS: linux-azure, Ubuntu:18.04:LTS: linux-azure-5.3, Ubuntu:18.04:LTS: linux-azure-edge, Ubuntu:18.04:LTS: linux-gcp, Ubuntu:18.04:LTS: linux-gcp-5.3, Ubuntu:18.04:LTS: linux-gke-4.15, Ubuntu:18.04:LTS: linux-gke-5.4 and 155 more

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).

Ein Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen, möglicherweise einen Denial-of-Service-Angriff auszulösen, Daten zu manipulieren oder offenzulegen oder Sicherheitsmaßnahmen zu umgehen.