diff options
Diffstat (limited to 'util.c')
| -rw-r--r-- | util.c | 54 |
1 files changed, 54 insertions, 0 deletions
@@ -34,6 +34,9 @@ #include "passt.h" #include "packet.h" #include "log.h" +#ifdef HAS_GETRANDOM +#include <sys/random.h> +#endif /** * sock_l4_sa() - Create and bind socket to socket address, add to epoll list @@ -783,3 +786,54 @@ bool snprintf_check(char *str, size_t size, const char *format, ...) return false; } + +#define DEV_RANDOM "/dev/random" + +/** + * raw_random() - Get high quality random bytes + * @buf: Buffer to fill with random bytes + * @buflen: Number of bytes of random data to put in @buf + * + * Assumes that the random data is essential, and will die() if unable to obtain + * it. + */ +void raw_random(void *buf, size_t buflen) +{ + size_t random_read = 0; +#ifndef HAS_GETRANDOM + int fd = open(DEV_RANDOM, O_RDONLY); + + if (fd < 0) + die_perror("Couldn't open %s", DEV_RANDOM); +#endif + + while (random_read < buflen) { + ssize_t ret; + +#ifdef HAS_GETRANDOM + ret = getrandom((char *)buf + random_read, + buflen - random_read, GRND_RANDOM); +#else + ret = read(dev_random, (char *)buf + random_read, + buflen - random_read); +#endif + + if (ret == -1 && errno == EINTR) + continue; + + if (ret < 0) + die_perror("Error on random data source"); + + if (ret == 0) + break; + + random_read += ret; + } + +#ifndef HAS_GETRANDOM + close(dev_random); +#endif + + if (random_read < buflen) + die("Unexpected EOF on random data source"); +} |