rand_unix.c: don't discard entropy bytes from syscall_random()
Fixes
Don't discard partial reads from syscall_random() and retry instead.
@@ -458,17 +458,25 @@ size_t rand_pool_acquire_entropy(RAND_POOL *pool)
unsigned char *buffer;
# ifdef OPENSSL_RAND_SEED_GETRANDOM
+ {
+ ssize_t bytes;
+ /* Maximum allowed number of consecutive unsuccessful attempts */
+ int attempts = 3;
+
bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
+ while (bytes_needed != 0 && attempts-- > 0) {
buffer = rand_pool_add_begin(pool, bytes_needed);
- if (buffer != NULL) {
- size_t bytes = 0;
-
- if (syscall_random(buffer, bytes_needed) == (int)bytes_needed)
- bytes = bytes_needed;
-
+ bytes = syscall_random(buffer, bytes_needed);
+ if (bytes > 0) {
rand_pool_add_end(pool, bytes, 8 * bytes);
- entropy_available = rand_pool_entropy_available(pool);
+ bytes_needed -= bytes;
+ attempts = 3; /* reset counter after successful attempt */
+ } else if (bytes < 0 && errno != EINTR) {
+ break;
+ }
}
+ }
+ entropy_available = rand_pool_entropy_available(pool);
if (entropy_available > 0)
return entropy_available;
# endif
