On 4/1/22 10:12, Guenter Roeck wrote:
> In __nat25_add_pppoe_tag(), the tag length is read from the tag data
> structure. The value is kept in network format, but read as raw value.
> With -Warray-bounds, this results in the following gcc error/warning
> when building the driver on a big endian system such as alpha.
>
> In function '__nat25_add_pppoe_tag',
> inlined from 'nat25_db_handle' at
> drivers/staging/r8188eu/core/rtw_br_ext.c:479:11:
> arch/alpha/include/asm/string.h:22:16: error:
> '__builtin_memcpy' forming offset [40, 2051] is out of the bounds
> [0, 40] of object 'tag_buf' with type 'unsigned char[40]'
>
> Add the missing ntohs().
>
> Fixes: 15865124feed ("staging: r8188eu: introduce new core dir for RTL8188eu driver")
> Cc: Phillip Potter <[email protected]>
> Signed-off-by: Guenter Roeck <[email protected]>
> ---
> drivers/staging/r8188eu/core/rtw_br_ext.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/staging/r8188eu/core/rtw_br_ext.c b/drivers/staging/r8188eu/core/rtw_br_ext.c
> index d68611ef22f8..31bcd495ec04 100644
> --- a/drivers/staging/r8188eu/core/rtw_br_ext.c
> +++ b/drivers/staging/r8188eu/core/rtw_br_ext.c
> @@ -70,7 +70,7 @@ static int __nat25_add_pppoe_tag(struct sk_buff *skb, struct pppoe_tag *tag)
> struct pppoe_hdr *ph = (struct pppoe_hdr *)(skb->data + ETH_HLEN);
> int data_len;
>
> - data_len = tag->tag_len + TAG_HDR_LEN;
> + data_len = htons(tag->tag_len) + TAG_HDR_LEN;
> if (skb_tailroom(skb) < data_len)
> return -1;
>
Strange that a BE compiler would generate a warning for what is actually an
execution error on LE platforms.
I prefer be16_to_cpu() to htons() as the former makes it clearer what is
happening, but I suppose that is a matter of choice.
Reviewed_by: Larry Finger <[email protected]>
Incidentally, Sparse shows 3 more __be16 problems in this routine. I leave their
fixing to you.
Larry