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

thunderbolt: Fix KASAN reported stack out-of-bounds read in tb_retimer_scan()

KASAN reported following issue:

BUG: KASAN: stack-out-of-bounds in tb_retimer_scan+0xffe/0x1550 [thunderbolt]
Read of size 4 at addr ffff88810111fc1c by task kworker/u56:0/11
CPU: 0 UID: 0 PID: 11 Comm: kworker/u56:0 Tainted: G U 6.11.0+ #1387
Tainted: [U]=USER
Workqueue: thunderbolt0 tb_handle_hotplug [thunderbolt]
Call Trace:

dump_stack_lvl+0x6c/0x90
print_report+0xd1/0x630
kasan_report+0xdb/0x110
__asan_report_load4_noabort+0x14/0x20
tb_retimer_scan+0xffe/0x1550 [thunderbolt]
tb_scan_port+0xa6f/0x2060 [thunderbolt]
tb_handle_hotplug+0x17b1/0x3080 [thunderbolt]
process_one_work+0x626/0x1100
worker_thread+0x6c8/0xfa0
kthread+0x2c8/0x3a0
ret_from_fork+0x3a/0x80
ret_from_fork_asm+0x1a/0x30

This happens because the loop variable still gets incremented by one so
max becomes 3 instead of 2, and this makes the second loop read past the
the array declared on the stack.

Fix this by assigning to max directly in the loop body.

References

• https://nvd.nist.gov/vuln/detail/CVE-2024-50227
• https://git.kernel.org/stable/c/08b2771e9270fbe1ed4fbbe93abe05ac7fe9861d
• https://git.kernel.org/stable/c/e9e1b20fae7de06ba36dd3f8dba858157bad233d