smb: client: fix overflow in passthrough ioctl bounds check

Overview

In the Linux kernel, the following vulnerability has been resolved:

smb: client: fix overflow in passthrough ioctl bounds check

smb2_ioctl_query_info() validates the PASSTHRU_FSCTL response payload before copying it to userspace.

The payload offset and length both come from 32-bit fields. The bounds check currently adds OutputOffset and qi.input_buffer_length directly, so the addition can wrap in 32-bit arithmetic before the result is compared against the response buffer length.

A malicious server can use a large OutputOffset and a small OutputCount to make the wrapped sum pass the bounds check. The later copy_to_user() then reads from io_rsp + OutputOffset, outside the response buffer.

Use size_add() for the offset plus length check so overflow is treated as out of bounds.

Affected

• Linux >= 2b1116bbe898aefdf584838448c6869f69851e0f < 175357ee0c596cb82054650dfa32fda51ad35aaa
• Linux >= 2b1116bbe898aefdf584838448c6869f69851e0f < dbd126539c098dba3159ce7d34b10b2daddcbd0f
• Linux >= 2b1116bbe898aefdf584838448c6869f69851e0f < 63feb687e89a3a52a31e6e01764117cc500f1974
• Linux >= 2b1116bbe898aefdf584838448c6869f69851e0f < 160045fc943f6c46b227644261252c8a22b8a87a
• Linux >= 2b1116bbe898aefdf584838448c6869f69851e0f < b30771b69eafae750afb7385fbcc3d77ed3f3670
• Linux >= 2b1116bbe898aefdf584838448c6869f69851e0f < 1627e7d5c9b09721a141d07cedb178882f1ded67
• Linux >= 2b1116bbe898aefdf584838448c6869f69851e0f < 1a638c55f2db6cb2296e5e3138015dd8fd9d4aa9
• Linux >= 2b1116bbe898aefdf584838448c6869f69851e0f < a4f27ad055392fa164f5649e89a3637b033c5fcc
• Linux 2005c32ec99ee2490e8131b3953f3f212009ffea
• Linux >= 5.4.69 < 5.5
• Linux 5.5

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.