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 via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions).
While there, use struct_size() helper, instead of the open-coded version, to calculate the size for the allocation of the whole flexible structure, including of course, the flexible-array member.
This code was found with the help of Coccinelle, and audited and fixed manually.
Signed-off-by: Gustavo A. R. Silva gustavoars@kernel.org --- drivers/staging/greybus/raw.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/greybus/raw.c b/drivers/staging/greybus/raw.c index a00978c8e1d2..b9c6eff7cdc1 100644 --- a/drivers/staging/greybus/raw.c +++ b/drivers/staging/greybus/raw.c @@ -29,7 +29,7 @@ struct gb_raw { struct raw_data { struct list_head entry; u32 len; - u8 data[]; + u8 data[] __counted_by(len); };
static const struct class raw_class = { @@ -73,7 +73,7 @@ static int receive_data(struct gb_raw *raw, u32 len, u8 *data) goto exit; }
- raw_data = kmalloc(sizeof(*raw_data) + len, GFP_KERNEL); + raw_data = kmalloc(struct_size(raw_data, data, len), GFP_KERNEL); if (!raw_data) { retval = -ENOMEM; goto exit;