[PATCH v2 1/2] lib: uuid: use RNG device if present

[matthias . bgg]

From: Matthias Brugger <mbrug...@suse.com>

When calculating a random UUID we use a weak seed.
Use a RNG device if present to increase entropy.

Signed-off-by: Matthias Brugger <mbrug...@suse.com>

---

Changes in v2:
- fix dm_rng_read() parameters
- add missing include

 lib/uuid.c | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/lib/uuid.c b/lib/uuid.c
index e62d5ca264..e3487380c3 100644
--- a/lib/uuid.c
+++ b/lib/uuid.c
@@ -15,6 +15,8 @@
 #include <asm/io.h>
 #include <part_efi.h>
 #include <malloc.h>
+#include <dm/uclass.h>
+#include <rng.h>
 
 /*
  * UUID - Universally Unique IDentifier - 128 bits unique number.
@@ -249,9 +251,22 @@ void gen_rand_uuid(unsigned char *uuid_bin)
 {
        u32 ptr[4];
        struct uuid *uuid = (struct uuid *)ptr;
-       int i;
-
-       srand(get_ticks() + rand());
+       int i, ret;
+       struct udevice *devp;
+       u8 randv = 0;
+
+#if defined(CONFIG_DM_RNG)
+       ret = uclass_get_device(UCLASS_RNG, 0, &devp);
+       if (ret) {
+               ret = dm_rng_read(devp, &randv, sizeof(randv));
+               if (ret < 0)
+                       randv = 0;
+       }
+       if (randv)
+               srand(randv);
+       else
+#endif
+               srand(get_ticks() + rand());
 
        /* Set all fields randomly */
        for (i = 0; i < 4; i++)
-- 
2.29.2