Add function to generate random identifier
The function is a wrapper on top of getrandom() (if available via glibc) or
corresponding syscall. If neither is available than failure is always
returned.
It's intended to generate small random data good enough for session
identifiers and keys. To generate long-term cryptographic keys it's
better to use special crypto libraries (like GnuTLS for example)
instead.
As an example it's used to replace old insecure random number generator
in osmo-auc-gen utility.
Change-Id: I0241b814ea4c4ce1458f7ad76e31d390383c2048
Related: OS#1694
diff --git a/utils/osmo-auc-gen.c b/utils/osmo-auc-gen.c
index 1f5c838..9d1215c 100644
--- a/utils/osmo-auc-gen.c
+++ b/utils/osmo-auc-gen.c
@@ -34,6 +34,7 @@
#include <osmocom/crypt/auth.h>
#include <osmocom/core/utils.h>
+#include <osmocom/gsm/gsm_utils.h>
static void dump_triplets_dat(struct osmo_auth_vector *vec)
{
@@ -247,14 +248,11 @@
}
if (!rand_is_set) {
- int i;
- printf("WARNING: We're using really weak random numbers!\n\n");
- srand(time(NULL));
-
- for (i = 0; i < 4; ++i) {
- uint32_t r;
- r = rand();
- memcpy(&_rand[i*4], &r, 4);
+ rc = osmo_get_rand_id(_rand, 16);
+ if (rc < 0) {
+ fprintf(stderr, "\nError: unable to obtain secure random numbers: %s!\n",
+ strerror(-rc));
+ exit(3);
}
}