diff options
Diffstat (limited to 'util/libreboot-utils/lib')
| -rw-r--r-- | util/libreboot-utils/lib/rand.c | 43 |
1 files changed, 35 insertions, 8 deletions
diff --git a/util/libreboot-utils/lib/rand.c b/util/libreboot-utils/lib/rand.c index c4cf008c..bfcde5ac 100644 --- a/util/libreboot-utils/lib/rand.c +++ b/util/libreboot-utils/lib/rand.c @@ -59,7 +59,6 @@ rlong(void) { size_t rval; int saved_errno = errno; - errno = 0; #if (defined(__OpenBSD__) || defined(__FreeBSD__) || \ defined(__NetBSD__) || defined(__APPLE__) || \ @@ -68,12 +67,39 @@ rlong(void) arc4random_buf(&rval, sizeof(size_t)); goto out; +#elif defined(USE_URANDOM) && \ + ((USE_URANDOM) > 0) + + /* Use of /dev/urandom is ill advised, due + to FD exhaustion */ + + int fd = -1; + ssize_t rc = 0; + + errno = 0; + + if ((fd = open("/dev/urandom", O_RDONLY)) < 0) + goto err; + +retry_rand: + + if ((rc = read(fd, &rval, sizeof(rval))) < 0) { + if (errno == EINTR || errno == EAGAIN) + goto retry_rand; + goto err; + } + + if ((rval += (size_t)rc) < sizeof(rval)) + goto retry_rand; + #elif defined(__linux__) size_t off = 0; size_t len = sizeof(rval); ssize_t rc; + errno = 0; + retry_rand: rc = (ssize_t)syscall(SYS_getrandom, (char *)&rval + off, len - off, 0); @@ -91,6 +117,13 @@ retry_rand: goto retry_rand; goto out; +#else +#error Unsupported operating system (possibly unsecure randomisation) +#endif + +out: + errno = saved_errno; + return rval; err: /* * getrandom can return with error, but arc4random @@ -103,12 +136,6 @@ err: "Randomisation failure, possibly unsupported in your kernel."); exit(EXIT_FAILURE); -#else -#error Unsupported operating system (possibly unsecure randomisation) -#endif - -out: - errno = saved_errno; - return rval; + return 0; } #endif |