diff options
| author | Leah Rowe <leah@libreboot.org> | 2026-03-19 18:34:28 +0000 |
|---|---|---|
| committer | Leah Rowe <leah@libreboot.org> | 2026-03-19 18:34:28 +0000 |
| commit | f8b07dba2932714507f7ead6b8464ba3157d84bd (patch) | |
| tree | 3e16546c3827d7a18f5b14ec28217161eb0f01f2 /util/nvmutil/include/common.h | |
| parent | 7c66a788bdfc8136a603eec6d805b75cc382b239 (diff) | |
util/nvmutil: rand: use getrandom on newer linux
we still fall back to the old /dev/urandom read
on older linux, via runtime detection (ENOSYS).
getrandom is better, because it guarantees entropy
via blocking, and works even when /dev/urandom
is unavailable.
it has the same practical benefit as arc4random,
which i use on bsd. linux can have arc4random,
but not every linux libc has it, so it's better
to use getrandom on linux.
older linux will fall back to /dev/urandom
Signed-off-by: Leah Rowe <leah@libreboot.org>
Diffstat (limited to 'util/nvmutil/include/common.h')
| -rw-r--r-- | util/nvmutil/include/common.h | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/util/nvmutil/include/common.h b/util/nvmutil/include/common.h index 36218d25..0a3beeac 100644 --- a/util/nvmutil/include/common.h +++ b/util/nvmutil/include/common.h @@ -9,6 +9,25 @@ #include <sys/stat.h> #include <limits.h> +/* for linux getrandom + */ +#if defined(__linux__) +#include <errno.h> +#if defined(__has_include) +#if __has_include(<sys/random.h>) +#include <sys/random.h> +#define HAVE_GETRANDOM 1 +#endif +#endif +#if !defined(HAVE_GETRANDOM) +#include <sys/syscall.h> +#if defined(SYS_getrandom) +#define HAVE_GETRANDOM_SYSCALL 1 +#endif +#endif + +#endif + #define items(x) (sizeof((x)) / sizeof((x)[0])) /* system prototypes @@ -318,6 +337,12 @@ void set_mac_nib(unsigned long mac_str_pos, unsigned long mac_byte_pos, unsigned long mac_nib_pos); unsigned short hextonum(char ch_s); unsigned long rlong(void); +#if defined(__linux__) +#if defined(HAVE_GETRANDOM) || \ + defined(HAVE_GETRANDOM_SYSCALL) +int fallback_rand_getrandom(void *buf, size_t len); +#endif +#endif void write_mac_part(unsigned long partnum); /* Helper functions for command: dump |