CVE-2024-43825: iio: Fix the sorting functionality in iio_gts_build_avail_time_table

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

iio: Fix the sorting functionality in iiogtsbuildavailtimetable

The sorting in iiogtsbuildavailtimetable is not working as intended. It could result in an out-of-bounds access when the time is zero.

Here are more details:

1. When the gts->itimetable[i].timeus is zero, e.g., the time sequence is 3, 0, 1, the inner for-loop will not terminate and do out-of-bound writes. This is because once times[j] > new, the value new will be added in the current position and the times[j] will be moved to j+1 position, which makes the if-condition always hold. Meanwhile, idx will be added one, making the loop keep running without termination and out-of-bound write. 2. If none of the gts->itimetable[i].timeus is zero, the elements will just be copied without being sorted as described in the comment "Sort times from all tables to one and remove duplicates".

For more details, please refer to https://lore.kernel.org/all/6dd0d822-046c-4dd2-9532-79d7ab96ec05@gmail.com.