2021-08-19 20:29:12

by Kees Cook

[permalink] [raw]
Subject: [PATCH 3/3] pcmcia: ray_cs: Split memcpy() to avoid bounds check warning

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.

Split memcpy() for each address range to help memcpy() correctly reason
about the bounds checking. Avoids the future warning:

In function 'fortify_memcpy_chk',
inlined from 'memcpy_toio' at ./include/asm-generic/io.h:1204:2,
inlined from 'ray_build_header.constprop' at drivers/net/wireless/ray_cs.c:984:3:
./include/linux/fortify-string.h:285:4: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
285 | __write_overflow_field(p_size_field, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Cc: Kalle Valo <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
drivers/net/wireless/ray_cs.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ray_cs.c b/drivers/net/wireless/ray_cs.c
index 590bd974d94f..d57bbe551630 100644
--- a/drivers/net/wireless/ray_cs.c
+++ b/drivers/net/wireless/ray_cs.c
@@ -982,7 +982,9 @@ AP to AP 1 1 dest AP src AP dest source
if (local->net_type == ADHOC) {
writeb(0, &ptx->mac.frame_ctl_2);
memcpy_toio(ptx->mac.addr_1, ((struct ethhdr *)data)->h_dest,
- 2 * ADDRLEN);
+ memcpy_toio(ptx->mac.addr_2, ((struct ethhdr *)data)->h_source,
memcpy_toio(ptx->mac.addr_3, local->bss_id, ADDRLEN);
} else { /* infrastructure */