CVE-2026-93119usb: ljca: bound bank_num in ljca_enumerate_gpio()

Official description

In the Linux kernel, the following vulnerability has been resolved: usb: ljca: bound bank_num in ljca_enumerate_gpio() ljca_enumerate_gpio() reads desc->bank_num from the device and loops valid_pin[i] = get_unaligned_le32(...) for i < bank_num. valid_pin[] holds only LJCA_MAX_GPIO_NUM / 32 = 2 entries. Two checks run before the loop. The reply length must match struct_size(desc, bank_desc, bank_num). The product pins_per_bank * bank_num must not exceed LJCA_MAX_GPIO_NUM. Neither one bounds bank_num against the size of valid_pin[]. The reply is capped at LJCA_MAX_PAYLOAD_SIZE (60) bytes, so the struct_size check limits bank_num to 9. A device that reports bank_num 9 with pins_per_bank 7 still passes both checks. gpio_num is 63 and the reply is 56 bytes. The loop then writes nine u32 into the two entry array and overruns valid_pin[] on the stack. A broken or malicious LJCA device can therefore overflow the stack. Reject a bank_num that does not fit valid_pin[].

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/0069593170a3d177de793c9a0b36989c4f069111
• https://git.kernel.org/stable/c/aed958c4f784a29cf42abb3e54af51a16bddde46
• https://git.kernel.org/stable/c/9c4bc8f7426aa001387800bf0140bfc5087a6de3
• https://git.kernel.org/stable/c/dd9483726d0f16c1a56879c3edb65128259a4e2b