Patch "iio: Fix the sorting functionality in iio_gts_build_avail_time_table" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    iio: Fix the sorting functionality in iio_gts_build_avail_time_table

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     iio-fix-the-sorting-functionality-in-iio_gts_build_a.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit d9825578d7875f539b0c87f4a3d89a82c8fee651
Author: Chenyuan Yang <chenyuan0y@xxxxxxxxx>
Date:   Tue Apr 30 15:44:53 2024 +0300

    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@xxxxxxxxx.
    
    Reported-by: Chenyuan Yang <chenyuan0y@xxxxxxxxx>
    Suggested-by: Matti Vaittinen <mazziesaccount@xxxxxxxxx>
    Fixes: 38416c28e168 ("iio: light: Add gain-time-scale helpers")
    Signed-off-by: Chenyuan Yang <chenyuan0y@xxxxxxxxx>
    Co-developed-by: Matti Vaittinen <mazziesaccount@xxxxxxxxx>
    Signed-off-by: Matti Vaittinen <mazziesaccount@xxxxxxxxx>
    Link: https://lore.kernel.org/r/d501ade8c1f7b202d34c6404eda423489cab1df5.1714480171.git.mazziesaccount@xxxxxxxxx
    Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/iio/industrialio-gts-helper.c b/drivers/iio/industrialio-gts-helper.c
index b51eb6cb766f3..59d7615c0f565 100644
--- a/drivers/iio/industrialio-gts-helper.c
+++ b/drivers/iio/industrialio-gts-helper.c
@@ -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;
 			}
 		}
 	}