diff options
Diffstat (limited to 'wrapper.c')
| -rw-r--r-- | wrapper.c | 81 |
1 files changed, 70 insertions, 11 deletions
@@ -463,8 +463,6 @@ int git_mkstemps_mode(char *pattern, int suffix_len, int mode) static const int num_letters = ARRAY_SIZE(letters) - 1; static const char x_pattern[] = "XXXXXX"; static const int num_x = ARRAY_SIZE(x_pattern) - 1; - uint64_t value; - struct timeval tv; char *filename_template; size_t len; int fd, count; @@ -485,12 +483,13 @@ int git_mkstemps_mode(char *pattern, int suffix_len, int mode) * Replace pattern's XXXXXX characters with randomness. * Try TMP_MAX different filenames. */ - gettimeofday(&tv, NULL); - value = ((uint64_t)tv.tv_usec << 16) ^ tv.tv_sec ^ getpid(); filename_template = &pattern[len - num_x - suffix_len]; for (count = 0; count < TMP_MAX; ++count) { - uint64_t v = value; int i; + uint64_t v; + if (csprng_bytes(&v, sizeof(v)) < 0) + return error_errno("unable to get random bytes for temporary file"); + /* Fill in the random bits. */ for (i = 0; i < num_x; i++) { filename_template[i] = letters[v % num_letters]; @@ -506,12 +505,6 @@ int git_mkstemps_mode(char *pattern, int suffix_len, int mode) */ if (errno != EEXIST) break; - /* - * This is a random value. It is only necessary that - * the next TMP_MAX values generated by adding 7777 to - * VALUE are different with (module 2^32). - */ - value += 7777; } /* We return the null string if we can't find a unique file name. */ pattern[0] = '\0'; @@ -702,3 +695,69 @@ int open_nofollow(const char *path, int flags) return open(path, flags); #endif } + +int csprng_bytes(void *buf, size_t len) +{ +#if defined(HAVE_ARC4RANDOM) || defined(HAVE_ARC4RANDOM_LIBBSD) + /* This function never returns an error. */ + arc4random_buf(buf, len); + return 0; +#elif defined(HAVE_GETRANDOM) + ssize_t res; + char *p = buf; + while (len) { + res = getrandom(p, len, 0); + if (res < 0) + return -1; + len -= res; + p += res; + } + return 0; +#elif defined(HAVE_GETENTROPY) + int res; + char *p = buf; + while (len) { + /* getentropy has a maximum size of 256 bytes. */ + size_t chunk = len < 256 ? len : 256; + res = getentropy(p, chunk); + if (res < 0) + return -1; + len -= chunk; + p += chunk; + } + return 0; +#elif defined(HAVE_RTLGENRANDOM) + if (!RtlGenRandom(buf, len)) + return -1; + return 0; +#elif defined(HAVE_OPENSSL_CSPRNG) + int res = RAND_bytes(buf, len); + if (res == 1) + return 0; + if (res == -1) + errno = ENOTSUP; + else + errno = EIO; + return -1; +#else + ssize_t res; + char *p = buf; + int fd, err; + fd = open("/dev/urandom", O_RDONLY); + if (fd < 0) + return -1; + while (len) { + res = xread(fd, p, len); + if (res < 0) { + err = errno; + close(fd); + errno = err; + return -1; + } + len -= res; + p += res; + } + close(fd); + return 0; +#endif +} |