From: Al Viro Date: Sun, 16 May 2021 20:59:56 +0000 (-0400) Subject: tomoyo: use vsnprintf() properly X-Git-Tag: v6.1-rc1~144^2~1 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=89868773fe862eabc049aaa6f6b587177b3f2ea6;p=thirdparty%2Flinux.git tomoyo: use vsnprintf() properly Idiomatic way to find how much space sprintf output would take is len = snprintf(NULL, 0, ...) + 1; Once upon a time there'd been libc implementations that blew chunks on that and somebody had come up with the following "cute" trick: len = snprintf((char *) &len, 1, ...) + 1; for doing the same. However, that's unidiomatic, harder to follow *and* any such libc implementation would violate both C99 and POSIX (since 2001). IOW, this kludge is best buried along with such libc implementations, nevermind getting cargo-culted into newer code. Our vsnprintf() does not suffer that braindamage, TYVM. Acked-by: Tetsuo Handa Signed-off-by: Al Viro --- diff --git a/security/tomoyo/audit.c b/security/tomoyo/audit.c index 023bedd9dfa30..7cf8fdbb29bfd 100644 --- a/security/tomoyo/audit.c +++ b/security/tomoyo/audit.c @@ -423,7 +423,7 @@ void tomoyo_write_log(struct tomoyo_request_info *r, const char *fmt, ...) int len; va_start(args, fmt); - len = vsnprintf((char *) &len, 1, fmt, args) + 1; + len = vsnprintf(NULL, 0, fmt, args) + 1; va_end(args); va_start(args, fmt); tomoyo_write_log2(r, len, fmt, args); diff --git a/security/tomoyo/common.c b/security/tomoyo/common.c index ff17abc96e5c1..f4cd9b58b2054 100644 --- a/security/tomoyo/common.c +++ b/security/tomoyo/common.c @@ -2057,7 +2057,7 @@ int tomoyo_supervisor(struct tomoyo_request_info *r, const char *fmt, ...) bool quota_exceeded = false; va_start(args, fmt); - len = vsnprintf((char *) &len, 1, fmt, args) + 1; + len = vsnprintf(NULL, 0, fmt, args) + 1; va_end(args); /* Write /sys/kernel/security/tomoyo/audit. */ va_start(args, fmt);