iio: Fix the sorting functionality in iio_gts_build_avail_time_table

[ Upstream commit 5acc3f971a01be48d5ff4252d8f9cdb87998cdfb ]

The sorting in iio_gts_build_avail_time_table 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->itime_table[i].time_us 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->itime_table[i].time_us 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.

Reported-by: Chenyuan Yang <chenyuan0y@gmail.com>
Suggested-by: Matti Vaittinen <mazziesaccount@gmail.com>
Fixes: 38416c28e1 ("iio: light: Add gain-time-scale helpers")
Signed-off-by: Chenyuan Yang <chenyuan0y@gmail.com>
Co-developed-by: Matti Vaittinen <mazziesaccount@gmail.com>
Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Link: https://lore.kernel.org/r/d501ade8c1f7b202d34c6404eda423489cab1df5.1714480171.git.mazziesaccount@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Chenyuan Yang 2024-04-30 15:44:53 +03:00 committed by Greg Kroah-Hartman
parent 0cd55c6e6d
commit 31ff8464ef
1 changed files with 5 additions and 2 deletions

View File

@ -362,17 +362,20 @@ static int iio_gts_build_avail_time_table(struct iio_gts *gts)
for (i = gts->num_itime - 1; i >= 0; i--) {
int new = gts->itime_table[i].time_us;
if (times[idx] < new) {
if (idx == 0 || times[idx - 1] < new) {
times[idx++] = new;
continue;
}
for (j = 0; j <= idx; j++) {
for (j = 0; j < idx; j++) {
if (times[j] == new)
break;
if (times[j] > new) {
memmove(&times[j + 1], &times[j],
(idx - j) * sizeof(int));
times[j] = new;
idx++;
break;
}
}
}