diff options
Diffstat (limited to 'util/nvmutil/lib/num.c')
| -rw-r--r-- | util/nvmutil/lib/num.c | 102 |
1 files changed, 97 insertions, 5 deletions
diff --git a/util/nvmutil/lib/num.c b/util/nvmutil/lib/num.c index 3ef2ad6f..0f795107 100644 --- a/util/nvmutil/lib/num.c +++ b/util/nvmutil/lib/num.c @@ -8,6 +8,10 @@ #include <sys/param.h> #endif #include <sys/types.h> +#if defined(FALLBACK_RAND_1989) && \ + (FALLBACK_RAND_1989) > 0 +#include <sys/time.h> +#endif #include <errno.h> #if !((defined(__OpenBSD__) && (OpenBSD) >= 201) || \ @@ -18,6 +22,10 @@ #include <limits.h> #include <stddef.h> #include <string.h> +#if defined(FALLBACK_RAND_1989) && \ + (FALLBACK_RAND_1989) > 0 +#include <time.h> +#endif #include <unistd.h> #include "../include/common.h" @@ -49,6 +57,8 @@ hextonum(char ch_s) unsigned long rlong(void) { +#if !(defined(FALLBACK_RAND_1989) && \ + ((FALLBACK_RAND_1989) > 0)) #if (defined(__OpenBSD__) && (OpenBSD) >= 201) || \ defined(__FreeBSD__) || \ defined(__NetBSD__) || defined(__APPLE__) @@ -131,8 +141,8 @@ retry_urandom_read: O_RDONLY | O_BINARY | O_NOFOLLOW | O_CLOEXEC); -#ifdef PORTABLE_RAND_DEV -#if (PORTABLE_RAND_DEV) > 0 +#ifdef USE_OLD_DEV_RANDOM +#if (USE_OLD_DEV_RANDOM) > 0 /* WARNING: * /dev/random may block * forever and does **NOT** @@ -190,15 +200,29 @@ rlong_next: off = 0; nr = -1; -/* TODO: will re-add timer-based fallback here #if defined(PORTABLE) */ - err(EIO, "Can't read from /dev/[ua]random"); return 0; - /* add portable timers here */ +#endif +#else /* FALLBACK_RAND_1989 */ + /* your computer is from a museum + */ + unsigned long mix = 0; + int nr; + + /* 100 times, for entropy + */ + for (nr = 0; nr < 100; nr++) + mix ^= fallback_rand_1989(); + + /* 101 times ;) + */ + return fallback_rand_1989(); #endif } +#if !(defined(FALLBACK_RAND_1989) && \ + ((FALLBACK_RAND_1989) > 0)) #if defined(__linux__) #if defined(HAVE_GETRANDOM) || \ defined(HAVE_GETRANDOM_SYSCALL) @@ -243,6 +267,74 @@ fallback_rand_getrandom(void *buf, size_t len) } #endif #endif +#else +/* nobody should use this + * (not crypto-safe) + */ +unsigned long +fallback_rand_1989(void) +{ + static unsigned long mix = 0; + static unsigned long counter = 0; + + struct timeval tv; + + gettimeofday(&tv, NULL); + + mix ^= (unsigned long)tv.tv_sec + ^ (unsigned long)tv.tv_usec + ^ (unsigned long)getpid() + ^ (unsigned long)&mix + ^ counter++ + ^ entropy_jitter(); + + /* + * Stack addresses can vary between + * calls, thus increasing entropy. + */ + mix ^= (unsigned long)&mix; + mix ^= (unsigned long)&tv; + mix ^= (unsigned long)&counter; + + return mix; +} + +unsigned long +entropy_jitter(void) +{ + unsigned long mix; + + struct timeval a, b; + long mix_diff; + + int c; + + mix = 0; + + gettimeofday(&a, NULL); + + for (c = 0; c < 32; c++) { + + getpid(); + gettimeofday(&b, NULL); + + /* + * prevent negative numbers to prevent overflow, + * which would bias rand to large numbers + */ + mix_diff = (long)(b.tv_usec - a.tv_usec); + if (mix_diff < 0) + mix_diff = -mix_diff; + + mix ^= (unsigned long)(mix_diff); + + mix ^= (unsigned long)&mix; + + } + + return mix; +} +#endif void check_bin(unsigned long a, const char *a_name) |