HID: bpf: cast size to ssize_t when checking hid_bpf_hw_request

Overview

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

HID: bpf: cast size to ssize_t when checking hid_bpf_hw_request

As reported by Sashiko: If a transport driver encounters a hardware error and returns a negative error code such as -EPIPE, ret is implicitly promoted to size_t when compared against size. This causes the negative error code to evaluate as a large positive number, making the (ret > size) condition true.

This silently converts the hardware error into a success return value and copies the unmodified buffer back, which could leave BPF programs operating on uninitialized or stale data.

Fix this by casting size into ssize_t to return the actual negative error code.

Affected

• Linux >= d6efaa50af62fb0790dd1fd4e7e5506b46312510 < 8b85ef0f561039e249c3f883c5280a1449c6dbee
• Linux >= 73c5b5aea1c443239c8cb4191b4af7a4bd6fd7b1 < 97be6396817bd3b11d06239010d27902940bfaa9
• Linux >= 2b658c1c442ec1cd9eec5ead98d68662c40fe645 < f9f808227554b2c116fd07dd2328ecd74ea3f411
• Linux >= 2b658c1c442ec1cd9eec5ead98d68662c40fe645 < 3afefbfe55c2a8a0c4bdf6f4cc1f773da120027c
• Linux eb57dae20fdf6f3069cdc07821fa3bb46de381d7
• Linux >= 6.12.78 < 6.12.113
• Linux >= 6.18.20 < 6.18.56
• Linux >= 6.19.10 < 6.20
• Linux 7.0

Remediation

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