linux-user/aarch64: Use qemu_guest_getrandom for PAUTH keys

Use a better interface for random numbers than rand() * 3.

Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 6 insertions, 23 deletions

diff --git a/linux-user/aarch64/cpu_loop.c b/linux-user/aarch64/cpu_loop.c
index d75fd9d3e2..cedad39ca0 100644
--- a/linux-user/aarch64/cpu_loop.c
+++ b/linux-user/aarch64/cpu_loop.c
@@ -20,6 +20,7 @@
 #include "qemu/osdep.h"
 #include "qemu.h"
 #include "cpu_loop-common.h"
+#include "qemu/guest-random.h"
 
 #define get_user_code_u32(x, gaddr, env)                \
     ({ abi_long __r = get_user_u32((x), (gaddr));       \
@@ -147,24 +148,6 @@ void cpu_loop(CPUARMState *env)
     }
 }
 
-static uint64_t arm_rand64(void)
-{
-    int shift = 64 - clz64(RAND_MAX);
-    int i, n = 64 / shift + (64 % shift != 0);
-    uint64_t ret = 0;
-
-    for (i = 0; i < n; i++) {
-        ret = (ret << shift) | rand();
-    }
-    return ret;
-}
-
-void arm_init_pauth_key(ARMPACKey *key)
-{
-    key->lo = arm_rand64();
-    key->hi = arm_rand64();
-}
-
 void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
 {
     ARMCPU *cpu = arm_env_get_cpu(env);
@@ -192,11 +175,11 @@ void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
 #endif
 
     if (cpu_isar_feature(aa64_pauth, cpu)) {
-        arm_init_pauth_key(&env->apia_key);
-        arm_init_pauth_key(&env->apib_key);
-        arm_init_pauth_key(&env->apda_key);
-        arm_init_pauth_key(&env->apdb_key);
-        arm_init_pauth_key(&env->apga_key);
+        qemu_guest_getrandom_nofail(&env->apia_key, sizeof(ARMPACKey));
+        qemu_guest_getrandom_nofail(&env->apib_key, sizeof(ARMPACKey));
+        qemu_guest_getrandom_nofail(&env->apda_key, sizeof(ARMPACKey));
+        qemu_guest_getrandom_nofail(&env->apdb_key, sizeof(ARMPACKey));
+        qemu_guest_getrandom_nofail(&env->apga_key, sizeof(ARMPACKey));
     }
 
     ts->stack_base = info->start_stack;