Re: [PATCH][next] wifi: brcmfmac: fweh: Add __counted_by for struct brcmf_fweh_queue_item and use struct_size()

From: Arend Van Spriel
Date: Tue Oct 10 2023 - 10:26:39 EST


On October 9, 2023 11:42:11 PM "Gustavo A. R. Silva" <gustavoars@xxxxxxxxxx> wrote:

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).

Also, relocate `event->datalen = datalen;` to before calling
`memcpy(event->data, data, datalen);`, so that the __counted_by
annotation has effect, and flex-array member `data` can be properly
bounds-checked at run-time.

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.

From the description above I think this change looks sane so...

Acked-by: Arend van Spriel <arend.vanspriel@xxxxxxxxxxxx>
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
---
drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)


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