Prepare for the coming implementation by GCC and Clang of the __counted_by attribute. Flexible array members annotated with __counted_by can have their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions).
As found with Coccinelle[1], add __counted_by for struct reset_control_array. Additionally, since the element count member must be set before accessing the annotated flexible array member, move its initialization earlier. [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci Cc: Philipp Zabel <p.za...@pengutronix.de> Signed-off-by: Kees Cook <keesc...@chromium.org> --- drivers/reset/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/reset/core.c b/drivers/reset/core.c index f0a076e94118..7ece6a8e9858 100644 --- a/drivers/reset/core.c +++ b/drivers/reset/core.c @@ -60,7 +60,7 @@ struct reset_control { struct reset_control_array { struct reset_control base; unsigned int num_rstcs; - struct reset_control *rstc[]; + struct reset_control *rstc[] __counted_by(num_rstcs); }; static const char *rcdev_name(struct reset_controller_dev *rcdev) @@ -1185,6 +1185,7 @@ of_reset_control_array_get(struct device_node *np, bool shared, bool optional, resets = kzalloc(struct_size(resets, rstc, num), GFP_KERNEL); if (!resets) return ERR_PTR(-ENOMEM); + resets->num_rstcs = num; for (i = 0; i < num; i++) { rstc = __of_reset_control_get(np, NULL, i, shared, optional, @@ -1193,7 +1194,6 @@ of_reset_control_array_get(struct device_node *np, bool shared, bool optional, goto err_rst; resets->rstc[i] = rstc; } - resets->num_rstcs = num; resets->base.array = true; return &resets->base; -- 2.34.1
