From: Kees Cook keescook@chromium.org
commit 2618a0dae09ef37728dab89ff60418cbe25ae6bd upstream.
With GCC 12, -Wstringop-overread was warning about an implicit cast from char[6] to char[8]. However, the extra 2 bytes are always thrown away, alignment doesn't matter, and the risk of hitting the edge of unallocated memory has been accepted, so this prototype can just be converted to a regular char *. Silences:
net/core/dev.c: In function ‘bpf_prog_run_generic_xdp’: net/core/dev.c:4618:21: warning: ‘ether_addr_equal_64bits’ reading 8 bytes from a region of size 6 [-Wstringop-overread] 4618 | orig_host = ether_addr_equal_64bits(eth->h_dest, > skb->dev->dev_addr); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ net/core/dev.c:4618:21: note: referencing argument 1 of type ‘const u8[8]’ {aka ‘const unsigned char[8]’} net/core/dev.c:4618:21: note: referencing argument 2 of type ‘const u8[8]’ {aka ‘const unsigned char[8]’} In file included from net/core/dev.c:91: include/linux/etherdevice.h:375:20: note: in a call to function ‘ether_addr_equal_64bits’ 375 | static inline bool ether_addr_equal_64bits(const u8 addr1[6+2], | ^~~~~~~~~~~~~~~~~~~~~~~
Reported-by: Marc Kleine-Budde mkl@pengutronix.de Tested-by: Marc Kleine-Budde mkl@pengutronix.de Link: https://lore.kernel.org/netdev/20220212090811.uuzk6d76agw2vv73@pengutronix.d... Cc: Jakub Kicinski kuba@kernel.org Cc: "David S. Miller" davem@davemloft.net Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook keescook@chromium.org Signed-off-by: David S. Miller davem@davemloft.net Cc: Khem Raj raj.khem@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/linux/etherdevice.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
--- a/include/linux/etherdevice.h +++ b/include/linux/etherdevice.h @@ -127,7 +127,7 @@ static inline bool is_multicast_ether_ad #endif }
-static inline bool is_multicast_ether_addr_64bits(const u8 addr[6+2]) +static inline bool is_multicast_ether_addr_64bits(const u8 *addr) { #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64 #ifdef __BIG_ENDIAN @@ -352,8 +352,7 @@ static inline bool ether_addr_equal(cons * Please note that alignment of addr1 & addr2 are only guaranteed to be 16 bits. */
-static inline bool ether_addr_equal_64bits(const u8 addr1[6+2], - const u8 addr2[6+2]) +static inline bool ether_addr_equal_64bits(const u8 *addr1, const u8 *addr2) { #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64 u64 fold = (*(const u64 *)addr1) ^ (*(const u64 *)addr2);