Re: [PATCH 05/32] brcmfmac: Use mem_to_flex_dup() with struct brcmf_fweh_queue_item

Arend van Spriel
2022-05-16T12:50:00Z

[-- Attachment #1: Type: text/plain, Size: 2603 bytes --]

On 5/4/2022 3:44 AM, Kees Cook wrote:
> As part of the work to perform bounds checking on all memcpy() uses,
> replace the open-coded a deserialization of bytes out of memory into a
> trailing flexible array by using a flex_array.h helper to perform the
> allocation, bounds checking, and copying.
>
Reviewed-by: Arend van Spriel <aspriel@gmail.com>
> Cc: Franky Lin <franky.lin@broadcom.com>
> Cc: Hante Meuleman <hante.meuleman@broadcom.com>
> Cc: Kalle Valo <kvalo@kernel.org>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: linux-wireless@vger.kernel.org
> Cc: brcm80211-dev-list.pdl@broadcom.com
> Cc: SHA-cyfmac-dev-list@infineon.com
> Cc: netdev@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> .../net/wireless/broadcom/brcm80211/brcmfmac/fweh.c | 11 ++++-------
> 1 file changed, 4 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c
> index bc3f4e4edcdf..bea798ca6466 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c
> @@ -32,8 +32,8 @@ struct brcmf_fweh_queue_item {
> u8 ifidx;
> u8 ifaddr[ETH_ALEN];
> struct brcmf_event_msg_be emsg;
> - u32 datalen;
> - u8 data[];
> + DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(u32, datalen);
> + DECLARE_FLEX_ARRAY_ELEMENTS(u8, data);
> };
>
> /*
> @@ -395,7 +395,7 @@ void brcmf_fweh_process_event(struct brcmf_pub *drvr,
> {
> enum brcmf_fweh_event_code code;
> struct brcmf_fweh_info *fweh = &drvr->fweh;
> - struct brcmf_fweh_queue_item *event;
> + struct brcmf_fweh_queue_item *event = NULL;
> void *data;
> u32 datalen;
>
> @@ -414,8 +414,7 @@ void brcmf_fweh_process_event(struct brcmf_pub *drvr,
> datalen + sizeof(*event_packet) > packet_len)
> return;
>
> - event = kzalloc(sizeof(*event) + datalen, gfp);
> - if (!event)
> + if (mem_to_flex_dup(&event, data, datalen, gfp))
> return;
>
> event->code = code;
> @@ -423,8 +422,6 @@ void brcmf_fweh_process_event(struct brcmf_pub *drvr,
>
> /* use memcpy to get aligned event message */
> memcpy(&event->emsg, &event_packet->msg, sizeof(event->emsg));
> - memcpy(event->data, data, datalen);
> - event->datalen = datalen;

So does mem_to_flex_dup() store event->datalen?

Don't have the entire thread so missing bits and pieces, but at least
this raises questions for me.

Thanks,
Arend

[-- Attachment #2: S/MIME Cryptographic Signature --]
[-- Type: application/pkcs7-signature, Size: 4219 bytes --]