Fix the following out-of-bounds warning by enclosing
structure members daddr and saddr into new struct addr:
arch/x86/include/asm/string_32.h:182:25: warning: '__builtin_memcpy' offset
[18, 23] from the object at 'sig' is out of the bounds of referenced subobject
'daddr' with type 'u8[6]' {aka 'unsigned char[6]'} at offset 11 [-Warray-bounds]
Refactor the code, accordingly:
$ pahole -C wl3501_md_req drivers/net/wireless/wl3501_cs.o
struct wl3501_md_req {
u16 next_blk; /* 0 2 */
u8 sig_id; /* 2 1 */
u8 routing; /* 3 1 */
u16 data; /* 4 2 */
u16 size; /* 6 2 */
u8 pri; /* 8 1 */
u8 service_class; /* 9 1 */
struct {
u8 daddr[6]; /* 10 6 */
u8 saddr[6]; /* 16 6 */
} addr; /* 10 12 */
/* size: 22, cachelines: 1, members: 8 */
/* last cacheline: 22 bytes */
};
The problem is that the original code is trying to copy data into a
couple of arrays adjacent to each other in a single call to memcpy().
Now that a new struct _addr_ enclosing those two adjacent arrays
is introduced, memcpy() doesn't overrun the length of &sig.daddr[0],
because the address of the new struct object _addr_ is used as
destination, instead.
Also, this helps with the ongoing efforts to enable -Warray-bounds and
avoid confusing the compiler.
Link: https://github.com/KSPP/linux/issues/109
Reported-by: kernel test robot <l...@intel.com>
Build-tested-by: kernel test robot <l...@intel.com>
Link: https://lore.kernel.org/lkml/60641d9b.2enledogsdcsoav2%25...@intel.com/
Signed-off-by: Gustavo A. R. Silva <gustavo...@kernel.org>
---
Changes in v2:
- Update changelog text.
- Replace a couple of magic numbers with new variable sig_addr_len.
drivers/net/wireless/wl3501.h | 6 ++++--
drivers/net/wireless/wl3501_cs.c | 7 ++++---
2 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/net/wireless/wl3501.h b/drivers/net/wireless/wl3501.h
index e98e04ee9a2c..ef9d605d8c88 100644
--- a/drivers/net/wireless/wl3501.h
+++ b/drivers/net/wireless/wl3501.h
@@ -471,8 +471,10 @@ struct wl3501_md_req {
u16 size;
u8 pri;
u8 service_class;
- u8 daddr[ETH_ALEN];
- u8 saddr[ETH_ALEN];
+ struct {
+ u8 daddr[ETH_ALEN];
+ u8 saddr[ETH_ALEN];
+ } addr;
};
struct wl3501_md_ind {
diff --git a/drivers/net/wireless/wl3501_cs.c b/drivers/net/wireless/wl3501_cs.c
index 8ca5789c7b37..e149ef81d6cc 100644
--- a/drivers/net/wireless/wl3501_cs.c
+++ b/drivers/net/wireless/wl3501_cs.c
@@ -469,6 +469,7 @@ static int wl3501_send_pkt(struct wl3501_card *this, u8
*data, u16 len)
struct wl3501_md_req sig = {
.sig_id = WL3501_SIG_MD_REQ,
};
+ size_t sig_addr_len = sizeof(sig.addr);
u8 *pdata = (char *)data;
int rc = -EIO;
@@ -484,9 +485,9 @@ static int wl3501_send_pkt(struct wl3501_card *this, u8
*data, u16 len)
goto out;
}
rc = 0;
- memcpy(&sig.daddr[0], pdata, 12);
- pktlen = len - 12;
- pdata += 12;
+ memcpy(&sig.addr, pdata, sig_addr_len);
+ pktlen = len - sig_addr_len;
+ pdata += sig_addr_len;
sig.data = bf;
if (((*pdata) * 256 + (*(pdata + 1))) > 1500) {
u8 addr4[ETH_ALEN] = {
--
2.27.0
