CVE-2023-53075

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

ftrace: Fix invalid address access in lookup_rec() when index is 0

KASAN reported follow problem:

BUG: KASAN: use-after-free in lookup_rec Read of size 8 at addr ffff000199270ff0 by task modprobe CPU: 2 Comm: modprobe Call trace: kasan_report __asan_load8 lookup_rec ftrace_location arch_check_ftrace_location check_kprobe_address_safe register_kprobe

When checking pg->records[pg->index - 1].ip in lookup_rec(), it can get a pg which is newly added to ftrace_pages_start in ftrace_process_locs(). Before the first pg->index++, index is 0 and accessing pg->records[-1].ip will cause this problem.

Don't check the ip when pg->index is 0.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.