In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memcpy(), memmove(), and memset(), avoid intentionally writing across neighboring fields.
Use struct_group() in struct rss_hdr around members imm_data and intr_gen, so they can be referenced together. This will allow memcpy() and sizeof() to more easily reason about sizes, improve readability, and avoid future warnings about writing beyond the end of imm_data.
"pahole" shows no size nor member offset changes to struct rss_hdr. "objdump -d" shows no object code changes.
Signed-off-by: Kees Cook keescook@chromium.org --- drivers/net/ethernet/chelsio/cxgb3/sge.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/chelsio/cxgb3/sge.c b/drivers/net/ethernet/chelsio/cxgb3/sge.c index cb5c79c43bc9..1ab1bd86a3a6 100644 --- a/drivers/net/ethernet/chelsio/cxgb3/sge.c +++ b/drivers/net/ethernet/chelsio/cxgb3/sge.c @@ -126,8 +126,10 @@ struct rsp_desc { /* response queue descriptor */ struct rss_header rss_hdr; __be32 flags; __be32 len_cq; - u8 imm_data[47]; - u8 intr_gen; + struct_group(immediate, + u8 imm_data[47]; + u8 intr_gen; + ); };
/* @@ -929,7 +931,8 @@ static inline struct sk_buff *get_imm_packet(const struct rsp_desc *resp)
if (skb) { __skb_put(skb, IMMED_PKT_SIZE); - skb_copy_to_linear_data(skb, resp->imm_data, IMMED_PKT_SIZE); + BUILD_BUG_ON(IMMED_PKT_SIZE != sizeof(resp->immediate)); + skb_copy_to_linear_data(skb, &resp->immediate, IMMED_PKT_SIZE); } return skb; }