🛡️ CVE-2024-50195 — kernel

posix-clock: Fix missing timespec64 check in pc_clock_settime()

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

posix-clock: Fix missing timespec64 check in pc_clock_settime()

As Andrew pointed out, it will make sense that the PTP core

checked timespec64 struct's tv_sec and tv_nsec range before calling

ptp->info->settime64().

As the man manual of clock_settime() said, if tp.tv_sec is negative or

tp.tv_nsec is outside the range [0..999,999,999], it should return EINVAL,

which include dynamic clocks which handles PTP clock, and the condition is

consistent with timespec64_valid(). As Thomas suggested, timespec64_valid()

only check the timespec is valid, but not ensure that the time is

in a valid range, so check it ahead using timespec64_valid_strict()

in pc_clock_settime() and return -EINVAL if not valid.

There are some drivers that use tp->tv_sec and tp->tv_nsec directly to

write registers without validity checks and assume that the higher layer

has checked it, which is dangerous and will benefit from this, such as

hclge_ptp_settime(), igb_ptp_settime_i210(), _rcar_gen4_ptp_settime(),

and some drivers can remove the checks of itself.