random-util: make use of GRND_INSECURE when it is defined

[thirdparty/systemd.git] / src / basic / random-util.c

diff --git a/src/basic/random-util.c b/src/basic/random-util.c
index c32e6e2aac92f137df07038f0233a64de52a277c..73cc7272db41cfd8c2331da5030043f6e31b8b1c 100644 (file)
--- a/src/basic/random-util.c
+++ b/src/basic/random-util.c
@@ -208,7 +208,9 @@ int genuine_random_bytes(void *p, size_t n, RandomFlags flags) {
         if (have_syscall != 0 && !HAS_FEATURE_MEMORY_SANITIZER) {
 
                 for (;;) {
-                        r = getrandom(p, n, FLAGS_SET(flags, RANDOM_BLOCK) ? 0 : GRND_NONBLOCK);
+                        r = getrandom(p, n,
+                                      (FLAGS_SET(flags, RANDOM_BLOCK) ? 0 : GRND_NONBLOCK) |
+                                      (FLAGS_SET(flags, RANDOM_ALLOW_INSECURE) ? GRND_INSECURE : 0));
                         if (r > 0) {
                                 have_syscall = true;
 
@@ -264,6 +266,18 @@ int genuine_random_bytes(void *p, size_t n, RandomFlags flags) {
 
                                 /* Use /dev/urandom instead */
                                 break;
+
+                        } else if (errno == EINVAL) {
+
+                                /* Most likely: unknown flag. We know that GRND_INSECURE might cause this,
+                                 * hence try without. */
+
+                                if (FLAGS_SET(flags, RANDOM_ALLOW_INSECURE)) {
+                                        flags = flags &~ RANDOM_ALLOW_INSECURE;
+                                        continue;
+                                }
+
+                                return -errno;
                         } else
                                 return -errno;
                 }
@@ -395,7 +409,7 @@ void random_bytes(void *p, size_t n) {
          * This function is hence not useful for generating UUIDs or cryptographic key material.
          */
 
-        if (genuine_random_bytes(p, n, RANDOM_EXTEND_WITH_PSEUDO|RANDOM_MAY_FAIL|RANDOM_ALLOW_RDRAND) >= 0)
+        if (genuine_random_bytes(p, n, RANDOM_EXTEND_WITH_PSEUDO|RANDOM_MAY_FAIL|RANDOM_ALLOW_RDRAND|RANDOM_ALLOW_INSECURE) >= 0)
                 return;
 
         /* If for some reason some user made /dev/urandom unavailable to us, or the kernel has no entropy, use a PRNG instead. */