From b968dec77d784e20d45a4d389be35301c9059b34 Mon Sep 17 00:00:00 2001
From: NRK <nrk@disroot.org>
Date: Mon, 31 Mar 2025 03:21:51 +0000
Subject: [PATCH] misc/random: improve the fallback case

c365e2f7 added av_random_bytes() to avoid multiple
threads/processes getting the same seed. but the fallback case
still suffers from it.

also mix in a function pointer, which hopefully is randomized
per process due to ASLR (20+ years old technology) along with
the stack position which will be different on different threads.
---
 misc/random.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/misc/random.c b/misc/random.c
index 3d6fe98a7b..d3b2a62da4 100644
--- a/misc/random.c
+++ b/misc/random.c
@@ -52,6 +52,8 @@ mp_rand_state mp_rand_seed(uint64_t seed)
             return ret;
         }
         seed = mp_raw_time_ns();
+        seed ^= (uintptr_t)&mp_rand_seed; // ASLR, hopefully
+        seed += (uintptr_t)&ret; // stack position
     }
 
     ret.v[0] = seed;