rand_unix.c: don't discard entropy bytes from /dev/*random
Don't discard partial reads from /dev/*random and retry instead.
@@ -493,22 +493,27 @@ size_t rand_pool_acquire_entropy(RAND_POOL *pool)
size_t i;
for (i = 0; bytes_needed > 0 && i < OSSL_NELEM(random_device_paths); i++) {
+ ssize_t bytes = 0;
+ /* Maximum allowed number of consecutive unsuccessful attempts */
+ int attempts = 3;
const int fd = get_random_device(i);
if (fd == -1)
continue;
+
+ while (bytes_needed != 0 && attempts-- > 0) {
buffer = rand_pool_add_begin(pool, bytes_needed);
- if (buffer != NULL) {
- const ssize_t n = read(fd, buffer, bytes_needed);
+ bytes = read(fd, buffer, bytes_needed);
- if (n <= 0) {
- close_random_device(i);
- continue;
+ if (bytes > 0) {
+ rand_pool_add_end(pool, bytes, 8 * bytes);
+ bytes_needed -= bytes;
+ attempts = 3; /* reset counter after successful attempt */
+ } else if (bytes < 0 && errno != EINTR) {
+ break;
}
-
- rand_pool_add_end(pool, n, 8 * n);
}
- if (!keep_random_devices_open)
+ if (bytes < 0 || !keep_random_devices_open)
close_random_device(i);
bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
