| Message ID | 20231206133822.620802-1-dmantipov@yandex.ru (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net: asix: fix fortify warning | expand |
On Wed, 6 Dec 2023 16:38:04 +0300 Dmitry Antipov wrote: > When compiling with gcc version 14.0.0 20231129 (experimental) and > CONFIG_FORTIFY_SOURCE=y, I've noticed the following warning: > > ... > In function 'fortify_memcpy_chk', > inlined from 'ax88796c_tx_fixup' at drivers/net/ethernet/asix/ax88796c_main.c:287:2: > ./include/linux/fortify-string.h:588:25: warning: call to '__read_overflow2_field' > declared with attribute warning: detected read beyond size of field (2nd parameter); > maybe use struct_group()? [-Wattribute-warning] > 588 | __read_overflow2_field(q_size_field, size); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > ... > > This call to 'memcpy()' is interpreted as an attempt to copy TX_OVERHEAD > (which is 8) bytes from 4-byte 'sop' field of 'struct tx_pkt_info' and > thus overread warning is issued. Since we actually wants to copy both > 'sop' and 'seg' fields at once, use the convenient 'struct_group()' here. Can we change the definition of TX_OVERHEAD to be sizeof_field(... tx_overhead), to make it clear that the two are indeed identical?
diff --git a/drivers/net/ethernet/asix/ax88796c_main.c b/drivers/net/ethernet/asix/ax88796c_main.c index e551ffaed20d..11e8996b33d7 100644 --- a/drivers/net/ethernet/asix/ax88796c_main.c +++ b/drivers/net/ethernet/asix/ax88796c_main.c @@ -284,7 +284,7 @@ ax88796c_tx_fixup(struct net_device *ndev, struct sk_buff_head *q) ax88796c_proc_tx_hdr(&info, skb->ip_summed); /* SOP and SEG header */ - memcpy(skb_push(skb, TX_OVERHEAD), &info.sop, TX_OVERHEAD); + memcpy(skb_push(skb, TX_OVERHEAD), &info.tx_overhead, TX_OVERHEAD); /* Write SPI TXQ header */ memcpy(skb_push(skb, spi_len), ax88796c_tx_cmd_buf, spi_len); diff --git a/drivers/net/ethernet/asix/ax88796c_main.h b/drivers/net/ethernet/asix/ax88796c_main.h index 4a83c991dcbe..678b47b29042 100644 --- a/drivers/net/ethernet/asix/ax88796c_main.h +++ b/drivers/net/ethernet/asix/ax88796c_main.h @@ -549,8 +549,10 @@ struct tx_eop_header { }; struct tx_pkt_info { - struct tx_sop_header sop; - struct tx_segment_header seg; + struct_group(tx_overhead, + struct tx_sop_header sop; + struct tx_segment_header seg; + ); struct tx_eop_header eop; u16 pkt_len; u16 seq_num;
When compiling with gcc version 14.0.0 20231129 (experimental) and CONFIG_FORTIFY_SOURCE=y, I've noticed the following warning: ... In function 'fortify_memcpy_chk', inlined from 'ax88796c_tx_fixup' at drivers/net/ethernet/asix/ax88796c_main.c:287:2: ./include/linux/fortify-string.h:588:25: warning: call to '__read_overflow2_field' declared with attribute warning: detected read beyond size of field (2nd parameter); maybe use struct_group()? [-Wattribute-warning] 588 | __read_overflow2_field(q_size_field, size); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ... This call to 'memcpy()' is interpreted as an attempt to copy TX_OVERHEAD (which is 8) bytes from 4-byte 'sop' field of 'struct tx_pkt_info' and thus overread warning is issued. Since we actually wants to copy both 'sop' and 'seg' fields at once, use the convenient 'struct_group()' here. Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru> --- drivers/net/ethernet/asix/ax88796c_main.c | 2 +- drivers/net/ethernet/asix/ax88796c_main.h | 6 ++++-- 2 files changed, 5 insertions(+), 3 deletions(-)