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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id ls14sm6239286pjb.0.2022.02.12.09.14.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 12 Feb 2022 09:14:51 -0800 (PST) From: Kees Cook To: Jakub Kicinski Cc: Kees Cook , Marc Kleine-Budde , "David S. Miller" , netdev@vger.kernel.org, Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , KP Singh , linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH] etherdevice: Adjust ether_addr* prototypes to silence -Wstringop-overead Date: Sat, 12 Feb 2022 09:14:49 -0800 Message-Id: <20220212171449.3000885-1-keescook@chromium.org> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2660; h=from:subject; bh=eVRNZb9+/scN9PRdT1Roirs8n4TTSE7XSUI757xJXEg=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBiB+sIVUHseDW+2l3grw1ne1EWyqjHGcHHhXf+atvk CB/an1KJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCYgfrCAAKCRCJcvTf3G3AJhs7D/ 443r8N7ZVCj+oC03dpcpCQpU9ac1ACqyZ9F+kU1vzi/Xba89SWTuaXrLQigr/9sinBhdsw9U4c9izS aErYdxXKko/9gLWHfjefU7EGgD1oyxii6K3YT0dwZnu2jPZ4RCzEqX6S1Y8D3gmWgSOEVLi7w/CA6J AAZ9WaQFEAyRbMyxm7XuT136wmilqpdt4+iH7jDoN4erjeF8FKU//m7GmVdaw/w8cDTz0+AEbZWZMT X5I65NUIHLa+ERT7uJ4qnwpM5OsJlmL/Ihat1ZPJUTx/Pxge3a2L8qOyhVPGfLR/1BkGRtAd3//c/d l5fzHgSW7tzHcHVy8p8v+v83q0wYHVcArkUlH+R8CjC0Knkgfxk+gDMeN3sz7YkR3/a35EZbYAunOb 6IpS8dCrMgiUgFNMyCToj+9TpLFSO29VUqXUuvfVl2/Ksw95IZdDpwCoibGjpQ5OvAz22wYwyH1ku3 HJQ6RlcUbjWbSuGFlyrBPc+PcNsDGm212Kld6//3CK/expJ6WlcO+xIrfMWyVF35bIyOwSQfE3LXVm 1LUW6E8SNahsfuMGkz4sXWwW4vOruDhb0WYccJqyQmOWqwiFscTaYcjYTXWvT/RhnM2DKBldJbpRzJ d68iGuY4StYQpqQnIRKBRmpfIj1bUfGW56ZDNNN8SGhojG/yZzXZJaEmW4Yg== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org 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 Tested-by: Marc Kleine-Budde Link: https://lore.kernel.org/netdev/20220212090811.uuzk6d76agw2vv73@pengutronix.de Cc: Jakub Kicinski Cc: "David S. Miller" Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook --- include/linux/etherdevice.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h index 2ad71cc90b37..92b10e67d5f8 100644 --- a/include/linux/etherdevice.h +++ b/include/linux/etherdevice.h @@ -134,7 +134,7 @@ static inline bool is_multicast_ether_addr(const u8 *addr) #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 @@ -372,8 +372,7 @@ static inline bool ether_addr_equal(const u8 *addr1, const u8 *addr2) * 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);