wireguard: Add __nonstring annotations for unterminated strings
Subsystems (3)
PATCH v2 1/1 wireguard: Add __nonstring annotations for unterminated strings
When a character array without a terminating NUL character has a static initializer, GCC 15's -Wunterminated-string-initialization will only warn if the array lacks the "nonstring" attribute[1]. Mark the arrays with __nonstring to correctly identify the char array as "not a C string" and thereby eliminate the warning:
../drivers/net/wireguard/cookie.c:29:56: warning: initializer-string for array of 'unsigned char' truncates NUL terminator but destination lacks 'nonstring' attribute (9 chars into 8 available) [-Wunterminated-string-initialization]
29 | static const u8 mac1_key_label[COOKIE_KEY_LABEL_LEN] = "mac1----";
| ^~~~~~~~~~../drivers/net/wireguard/cookie.c:30:58: warning: initializer-string for array of 'unsigned char' truncates NUL terminator but destination lacks 'nonstring' attribute (9 chars into 8 available) [-Wunterminated-string-initialization]
30 | static const u8 cookie_key_label[COOKIE_KEY_LABEL_LEN] = "cookie--";
| ^~~~~~~~~~../drivers/net/wireguard/noise.c:28:38: warning: initializer-string for array of 'unsigned char' truncates NUL terminator but destination lacks 'nonstring' attribute (38 chars into 37 available) [-Wunterminated-string-initialization]
28 | static const u8 handshake_name[37] = "Noise_IKpsk2_25519_ChaChaPoly_BLAKE2s";
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../drivers/net/wireguard/noise.c:29:39: warning: initializer-string for array of 'unsigned char' truncates NUL terminator but destination lacks 'nonstring' attribute (35 chars into 34 available) [-Wunterminated-string-initialization]
29 | static const u8 identifier_name[34] = "WireGuard v1 zx2c4 [email protected]";
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~The arrays are always used with their fixed size, so use __nonstring.
---
v2: Improve commit log, add cookie nonstrings too
v1: https://lore.kernel.org/lkml/[email protected]/
Cc: Jason A. Donenfeld <[email protected]>
Cc: "Jason A. Donenfeld" <[email protected]>
Cc: Andrew Lunn <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: Paolo Abeni <[email protected]>
Cc: [email protected]
Cc: [email protected]
--- drivers/net/wireguard/cookie.c | 4 ++-- drivers/net/wireguard/noise.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-)
drivers/net/wireguard/cookie.c +2 -2
@@ -26,8 +26,8 @@ void wg_cookie_checker_init(struct cookie_checker *checker, }enum {COOKIE_KEY_LABEL_LEN =8 }; -static const u8 mac1_key_label[COOKIE_KEY_LABEL_LEN ] ="mac1----" ; -static const u8 cookie_key_label[COOKIE_KEY_LABEL_LEN ] ="cookie--" ; +static const u8 mac1_key_label[COOKIE_KEY_LABEL_LEN] __nonstring = "mac1----"; +static const u8 cookie_key_label[COOKIE_KEY_LABEL_LEN] __nonstring = "cookie--"; static void precompute_key(u8 key[NOISE_SYMMETRIC_KEY_LEN], const u8 pubkey[NOISE_PUBLIC_KEY_LEN],
drivers/net/wireguard/noise.c +2 -2
@@ -25,8 +25,8 @@* <- e, ee, se, psk, {} */ -static const u8 handshake_name[37 ] ="Noise_IKpsk2_25519_ChaChaPoly_BLAKE2s" ; -static const u8 identifier_name[34 ] ="WireGuard v1 zx2c4 [email protected]" ; +static const u8 handshake_name[37] __nonstring = "Noise_IKpsk2_25519_ChaChaPoly_BLAKE2s"; +static const u8 identifier_name[34] __nonstring = "WireGuard v1 zx2c4 [email protected]";static u8 handshake_init_hash[NOISE_HASH_LEN ]__ro_after_init ;static u8 handshake_init_chaining_key[NOISE_HASH_LEN ]__ro_after_init ;static atomic64_t keypair_counter =ATOMIC64_INIT (0 );
Signature · 1 line
2.34.1
Quoted 19 lines · Kees Cook
When a character array without a terminating NUL character has a static initializer, GCC 15's -Wunterminated-string-initialization will only warn if the array lacks the "nonstring" attribute[1]. Mark the arrays with
__nonstringto correctly identify the char array as "not a C string" and thereby eliminate the warning:
../drivers/net/wireguard/cookie.c:29:56: warning: initializer-string for array of 'unsigned char' truncates NUL terminator but destination lacks 'nonstring' attribute (9 chars into 8 available) [-Wunterminated-string-initialization]
29 | static const u8 mac1_key_label[COOKIE_KEY_LABEL_LEN] = "mac1----";
| ^~~~~~~~~~../drivers/net/wireguard/cookie.c:30:58: warning: initializer-string for array of 'unsigned char' truncates NUL terminator but destination lacks 'nonstring' attribute (9 chars into 8 available) [-Wunterminated-string-initialization]
30 | static const u8 cookie_key_label[COOKIE_KEY_LABEL_LEN] = "cookie--";
| ^~~~~~~~~~../drivers/net/wireguard/noise.c:28:38: warning: initializer-string for array of 'unsigned char' truncates NUL terminator but destination lacks 'nonstring' attribute (38 chars into 37 available) [-Wunterminated-string-initialization]28 | static const u8 handshake_name[37] = "Noise_IKpsk2_25519_ChaChaPoly_BLAKE2s"; | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ../drivers/net/wireguard/noise.c:29:39: warning: initializer-string for array of 'unsigned char' truncates NUL terminator but destination lacks 'nonstring' attribute (35 chars into 34 available) [-Wunterminated-string-initialization] 29 | static const u8 identifier_name[34] = "WireGuard v1 zx2c4 [email protected]"; | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Quoted 7 lines
The arrays are always used with their fixed size, so use
__nonstring.Signed-off-by Kees Cook <[email protected]>---
v2: Improve commit log, add cookie nonstrings too
v1: https://lore.kernel.org/lkml/[email protected]/
Hi Kees,
Quoted 13 lines · Kees Cook
When a character array without a terminating NUL character has a static initializer, GCC 15's -Wunterminated-string-initialization will only warn if the array lacks the "nonstring" attribute[1]. Mark the arrays with
__nonstringto correctly identify the char array as "not a C string" and thereby eliminate the warning:
../drivers/net/wireguard/cookie.c:29:56: warning: initializer-string for array of 'unsigned char' truncates NUL terminator but destination lacks 'nonstring' attribute (9 chars into 8 available) [-Wunterminated-string-initialization]
29 | static const u8 mac1_key_label[COOKIE_KEY_LABEL_LEN] = "mac1----";
| ^~~~~~~~~~../drivers/net/wireguard/cookie.c:30:58: warning: initializer-string for array of 'unsigned char' truncates NUL terminator but destination lacks 'nonstring' attribute (9 chars into 8 available) [-Wunterminated-string-initialization]
30 | static const u8 cookie_key_label[COOKIE_KEY_LABEL_LEN] = "cookie--";
| ^~~~~~~~~~../drivers/net/wireguard/noise.c:28:38: warning: initializer-string for array of 'unsigned char' truncates NUL terminator but destination lacks 'nonstring' attribute (38 chars into 37 available) [-Wunterminated-string-initialization]
Quoted 8 lines
28 | static const u8 handshake_name[37] = "Noise_IKpsk2_25519_ChaChaPoly_BLAKE2s"; | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ../drivers/net/wireguard/noise.c:29:39: warning: initializer-string for array of 'unsigned char' truncates NUL terminator but destination lacks 'nonstring' attribute (35 chars into 34 available) [-Wunterminated-string-initialization] 29 | static const u8 identifier_name[34] = "WireGuard v1 zx2c4 [email protected]"; | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~The arrays are always used with their fixed size, so use
__nonstring.
Applied. Thanks for the patch.
Jason