Commit 2a626448 authored by Dmitry Antipov's avatar Dmitry Antipov Committed by Jakub Kicinski
Browse files

net: asix: fix fortify warning 



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 want to copy both
'sop' and 'seg' fields at once, use the convenient 'struct_group()' here.

Signed-off-by: default avatarDmitry Antipov <dmantipov@yandex.ru>
Acked-by: default avatarŁukasz Stelmach <l.stelmach@samsung.com>
Link: https://lore.kernel.org/r/20231211090535.9730-1-dmantipov@yandex.ru


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 609c767f

drivers/net/ethernet/asix/ax88796c_main.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

drivers/net/ethernet/asix/ax88796c_main.h

+5 −3
Original line number Diff line number Diff line
@@ -25,7 +25,7 @@ 
#define AX88796C_PHY_REGDUMP_LEN	14

#define AX88796C_PHY_ID			0x10



#define TX_OVERHEAD			8

#define TX_OVERHEAD     sizeof_field(struct tx_pkt_info, tx_overhead)

#define TX_EOP_SIZE			4



#define AX_MCAST_FILTER_SIZE		8
@@ -549,8 +549,10 @@ struct tx_eop_header { 
};



struct tx_pkt_info {

	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;