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") Co-developed-by: Chenyuan Yang <chenyuan0y@xxxxxxxxx> Signed-off-by: Chenyuan Yang <chenyuan0y@xxxxxxxxx> Co-developed-by: Matti Vaittinen <mazziesaccount@xxxxxxxxx> Signed-off-by: Matti Vaittinen <mazziesaccount@xxxxxxxxx> --- Original commit (by Chenyuan Yang) was amended by me to remove duplicates so that the user-space callers do not get multiple instances of same time as was discussed here: https://lore.kernel.org/all/a59061f8-5caa-43d4-bd4f-5ac4c39515ba@xxxxxxxxx/ --- drivers/iio/industrialio-gts-helper.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/iio/industrialio-gts-helper.c b/drivers/iio/industrialio-gts-helper.c index b51eb6cb766f..59d7615c0f56 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(×[j + 1], ×[j], (idx - j) * sizeof(int)); times[j] = new; idx++; + break; } } } -- 2.44.0 -- Matti Vaittinen, Linux device drivers ROHM Semiconductors, Finland SWDC Kiviharjunlenkki 1E 90220 OULU FINLAND ~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~ Simon says - in Latin please. ~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~ Thanks to Simon Glass for the translation =]
Attachment:
signature.asc
Description: PGP signature
