The compiler attribute __counted_by_ptr can be used by KASAN and UBSAN to detect out-of-bounds accesses to pointer fields in structs where a corresponding element count field is available.
In "struct iio_gts", there are multiple pointer fields associated with an element count. This patch annotates these pointer fields with "__counted_by_ptr" to improve runtime safety: - 'hwgain_table': counted by 'num_hwgain' - 'itime_table': counted by 'num_itime' - 'per_time_avail_scale_tables': counted by 'num_itime' - 'avail_all_scales_table': counted by 'num_avail_all_scales' - 'avail_time_tables': counted by 'num_avail_time_tables' To ensure that the count is set correctly before any pointer is accessed or assigned, we update "iio_init_iio_gts()" to set the counts prior to assigning the pointers. Cc: [email protected] Assisted-by: LLM Signed-off-by: Bill Wendling <[email protected]> Acked-by: Matti Vaittinen <[email protected]> Reviewed-by: Gustavo A. R. Silva <[email protected]> --- v2: Remove reordering of assignments. It's not necessary as an assignment of the pointer isn't an access that's checked by KASAN. --- include/linux/iio/iio-gts-helper.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/include/linux/iio/iio-gts-helper.h b/include/linux/iio/iio-gts-helper.h index 66f830ab9b49..7e7d3396ff1a 100644 --- a/include/linux/iio/iio-gts-helper.h +++ b/include/linux/iio/iio-gts-helper.h @@ -58,14 +58,14 @@ struct iio_itime_sel_mul { struct iio_gts { u64 max_scale; - const struct iio_gain_sel_pair *hwgain_table; + const struct iio_gain_sel_pair *hwgain_table __counted_by_ptr(num_hwgain); int num_hwgain; - const struct iio_itime_sel_mul *itime_table; + const struct iio_itime_sel_mul *itime_table __counted_by_ptr(num_itime); int num_itime; - int **per_time_avail_scale_tables; - int *avail_all_scales_table; + int **per_time_avail_scale_tables __counted_by_ptr(num_itime); + int *avail_all_scales_table __counted_by_ptr(num_avail_all_scales); int num_avail_all_scales; - int *avail_time_tables; + int *avail_time_tables __counted_by_ptr(num_avail_time_tables); int num_avail_time_tables; }; -- 2.56.0.rc1.310.g51773c2048-goog
