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.zabel@xxxxxxxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
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;