stdlib: Add arc4random, arc4random_buf, and arc4random_uniform (BZ #4417)

The implementation is based on scalar Chacha20 with per-thread cache.
It uses getrandom or /dev/urandom as fallback to get the initial entropy,
and reseeds the internal state on every 16MB of consumed buffer.

To improve performance and lower memory consumption the per-thread cache
is allocated lazily on first arc4random functions call, and if the
memory allocation fails getentropy or /dev/urandom is used as fallback.
The cache is also cleared on thread exit iff it was initialized (so if
arc4random is not called it is not touched).

Although it is lock-free, arc4random is still not async-signal-safe
(the per thread state is not updated atomically).

The ChaCha20 implementation is based on RFC8439 [1], omitting the final
XOR of the keystream with the plaintext because the plaintext is a
stream of zeros.  This strategy is similar to what OpenBSD arc4random
does.

The arc4random_uniform is based on previous work by Florian Weimer,
where the algorithm is based on Jérémie Lumbroso paper Optimal Discrete
Uniform Generation from Coin Flips, and Applications (2013) [2], who
credits Donald E. Knuth and Andrew C. Yao, The complexity of nonuniform
random number generation (1976), for solving the general case.

The main advantage of this method is the that the unit of randomness is not
the uniform random variable (uint32_t), but a random bit.  It optimizes the
internal buffer sampling by initially consuming a 32-bit random variable
and then sampling byte per byte.  Depending of the upper bound requested,
it might lead to better CPU utilization.

Checked on x86_64-linux-gnu, aarch64-linux, and powerpc64le-linux-gnu.

Co-authored-by: Florian Weimer <fweimer@redhat.com>
Reviewed-by: Yann Droneaud <ydroneaud@opteya.com>

[1] https://datatracker.ietf.org/doc/html/rfc8439
[2] https://arxiv.org/pdf/1304.1916.pdf

44 files changed, 178 insertions, 13 deletions

diff --git a/sysdeps/generic/not-cancel.h b/sysdeps/generic/not-cancel.h
index 2104efe..acceb9b 100644
--- a/sysdeps/generic/not-cancel.h
+++ b/sysdeps/generic/not-cancel.h
@@ -48,5 +48,7 @@
   (void) __writev (fd, iov, n)
 #define __fcntl64_nocancel(fd, cmd, ...) \
   __fcntl64 (fd, cmd, __VA_ARGS__)
+#define __getrandom_nocancel(buf, size, flags) \
+  __getrandom (buf, size, flags)
 
 #endif /* NOT_CANCEL_H  */
diff --git a/sysdeps/generic/tls-internal-struct.h b/sysdeps/generic/tls-internal-struct.h
index d76c715..a919158 100644
--- a/sysdeps/generic/tls-internal-struct.h
+++ b/sysdeps/generic/tls-internal-struct.h
@@ -23,6 +23,7 @@ struct tls_internal_t
 {
   char *strsignal_buf;
   char *strerror_l_buf;
+  struct arc4random_state_t *rand_state;
 };
 
 #endif
diff --git a/sysdeps/generic/tls-internal.c b/sysdeps/generic/tls-internal.c
index 898c20b..8a0f37d 100644
--- a/sysdeps/generic/tls-internal.c
+++ b/sysdeps/generic/tls-internal.c
@@ -16,6 +16,24 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
+#include <stdlib/arc4random.h>
+#include <string.h>
 #include <tls-internal.h>
 
 __thread struct tls_internal_t __tls_internal;
+
+void
+__glibc_tls_internal_free (void)
+{
+  free (__tls_internal.strsignal_buf);
+  free (__tls_internal.strerror_l_buf);
+
+  if (__tls_internal.rand_state != NULL)
+    {
+      /* Clear any lingering random state prior so if the thread stack is
+	 cached it won't leak any data.  */
+      explicit_bzero (__tls_internal.rand_state,
+		      sizeof (*__tls_internal.rand_state));
+      free (__tls_internal.rand_state);
+    }
+}
diff --git a/sysdeps/generic/tls-internal.h b/sysdeps/generic/tls-internal.h
index acb8ac9..3f53e4a 100644
--- a/sysdeps/generic/tls-internal.h
+++ b/sysdeps/generic/tls-internal.h
@@ -30,11 +30,6 @@ __glibc_tls_internal (void)
   return &__tls_internal;
 }
 
-static inline void
-__glibc_tls_internal_free (void)
-{
-  free (__tls_internal.strsignal_buf);
-  free (__tls_internal.strerror_l_buf);
-}
+extern void __glibc_tls_internal_free (void) attribute_hidden;
 
 #endif
diff --git a/sysdeps/mach/hurd/_Fork.c b/sysdeps/mach/hurd/_Fork.c
index e60b86f..667068c 100644
--- a/sysdeps/mach/hurd/_Fork.c
+++ b/sysdeps/mach/hurd/_Fork.c
@@ -662,6 +662,8 @@ retry:
       _hurd_malloc_fork_child ();
       call_function_static_weak (__malloc_fork_unlock_child);
 
+      call_function_static_weak (__arc4random_fork_subprocess);
+
       /* Run things that want to run in the child task to set up.  */
       RUN_HOOK (_hurd_fork_child_hook, ());
 
diff --git a/sysdeps/mach/hurd/i386/libc.abilist b/sysdeps/mach/hurd/i386/libc.abilist
index 66fb0e2..4e3200e 100644
--- a/sysdeps/mach/hurd/i386/libc.abilist
+++ b/sysdeps/mach/hurd/i386/libc.abilist
@@ -2289,6 +2289,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 close_range F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 mbrtoc8 F
 GLIBC_2.4 __confstr_chk F
diff --git a/sysdeps/mach/hurd/not-cancel.h b/sysdeps/mach/hurd/not-cancel.h
index 6ec92ce..9a3a7ed 100644
--- a/sysdeps/mach/hurd/not-cancel.h
+++ b/sysdeps/mach/hurd/not-cancel.h
@@ -74,6 +74,9 @@ __typeof (__fcntl) __fcntl_nocancel;
 #define __fcntl64_nocancel(...) \
   __fcntl_nocancel (__VA_ARGS__)
 
+#define __getrandom_nocancel(buf, size, flags) \
+  __getrandom (buf, size, flags)
+
 #if IS_IN (libc)
 hidden_proto (__close_nocancel)
 hidden_proto (__close_nocancel_nostatus)
diff --git a/sysdeps/nptl/_Fork.c b/sysdeps/nptl/_Fork.c
index dd56899..7dc0256 100644
--- a/sysdeps/nptl/_Fork.c
+++ b/sysdeps/nptl/_Fork.c
@@ -43,6 +43,8 @@ _Fork (void)
       self->robust_head.list = &self->robust_head;
       INTERNAL_SYSCALL_CALL (set_robust_list, &self->robust_head,
 			     sizeof (struct robust_list_head));
+
+      call_function_static_weak (__arc4random_fork_subprocess);
     }
   return pid;
 }
diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
index 516b029..b66fade 100644
--- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
@@ -2616,6 +2616,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist
index dde0889..f918bb2 100644
--- a/sysdeps/unix/sysv/linux/alpha/libc.abilist
+++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist
@@ -2713,6 +2713,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/arc/libc.abilist b/sysdeps/unix/sysv/linux/arc/libc.abilist
index ade44d3..093043a 100644
--- a/sysdeps/unix/sysv/linux/arc/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arc/libc.abilist
@@ -2377,6 +2377,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/arm/be/libc.abilist b/sysdeps/unix/sysv/linux/arm/be/libc.abilist
index 98b3370..e0668a8 100644
--- a/sysdeps/unix/sysv/linux/arm/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arm/be/libc.abilist
@@ -496,6 +496,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/arm/le/libc.abilist b/sysdeps/unix/sysv/linux/arm/le/libc.abilist
index 05dbbe5..d28e7c6 100644
--- a/sysdeps/unix/sysv/linux/arm/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arm/le/libc.abilist
@@ -493,6 +493,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/csky/libc.abilist b/sysdeps/unix/sysv/linux/csky/libc.abilist
index 430a243..922b050 100644
--- a/sysdeps/unix/sysv/linux/csky/libc.abilist
+++ b/sysdeps/unix/sysv/linux/csky/libc.abilist
@@ -2652,6 +2652,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist
index de44616..412144f 100644
--- a/sysdeps/unix/sysv/linux/hppa/libc.abilist
+++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist
@@ -2601,6 +2601,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist
index 18b4fbf..1343939 100644
--- a/sysdeps/unix/sysv/linux/i386/libc.abilist
+++ b/sysdeps/unix/sysv/linux/i386/libc.abilist
@@ -2785,6 +2785,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist
index a8e959d..02c65b6 100644
--- a/sysdeps/unix/sysv/linux/ia64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist
@@ -2551,6 +2551,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
index 3a7e4ef..0604029 100644
--- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
@@ -497,6 +497,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
index 864ad2c..af2be5c 100644
--- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
@@ -2728,6 +2728,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist
index 1630584..e090b8d 100644
--- a/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist
@@ -2701,6 +2701,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist
index a6debfd..8c5b2db 100644
--- a/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist
@@ -2698,6 +2698,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
index 2b53d88..6884713 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
@@ -2693,6 +2693,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
index 849aae4..daa44e6 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
@@ -2691,6 +2691,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
index 37f6c1b..6169188 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
@@ -2699,6 +2699,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
index ff1eb91..2f7f1cc 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
@@ -2602,6 +2602,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/nios2/libc.abilist b/sysdeps/unix/sysv/linux/nios2/libc.abilist
index 361b91f..58e9b48 100644
--- a/sysdeps/unix/sysv/linux/nios2/libc.abilist
+++ b/sysdeps/unix/sysv/linux/nios2/libc.abilist
@@ -2740,6 +2740,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/not-cancel.h b/sysdeps/unix/sysv/linux/not-cancel.h
index 75b9e0e..2c58d5a 100644
--- a/sysdeps/unix/sysv/linux/not-cancel.h
+++ b/sysdeps/unix/sysv/linux/not-cancel.h
@@ -67,6 +67,13 @@ __writev_nocancel_nostatus (int fd, const struct iovec *iov, int iovcnt)
   INTERNAL_SYSCALL_CALL (writev, fd, iov, iovcnt);
 }
 
+static inline int
+__getrandom_nocancel (void *buf, size_t buflen, unsigned int flags)
+{
+  return INTERNAL_SYSCALL_CALL (getrandom, buf, buflen, flags);
+}
+
+
 /* Uncancelable fcntl.  */
 __typeof (__fcntl) __fcntl64_nocancel;
 
diff --git a/sysdeps/unix/sysv/linux/or1k/libc.abilist b/sysdeps/unix/sysv/linux/or1k/libc.abilist
index cb91606..ffdb881 100644
--- a/sysdeps/unix/sysv/linux/or1k/libc.abilist
+++ b/sysdeps/unix/sysv/linux/or1k/libc.abilist
@@ -2123,6 +2123,9 @@ GLIBC_2.35 wprintf F
 GLIBC_2.35 write F
 GLIBC_2.35 writev F
 GLIBC_2.35 wscanf F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
index 1264aff..8c9ca32 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
@@ -2755,6 +2755,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
index f96d6e3..08a6604 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
@@ -2788,6 +2788,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
index e7082e1..849863e 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
@@ -2510,6 +2510,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
index 1032c7e..b2ccee0 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
@@ -2812,6 +2812,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist b/sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist
index f932db7..ff90d1b 100644
--- a/sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist
@@ -2379,6 +2379,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
index ccc53b0..f1017f6 100644
--- a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
@@ -2579,6 +2579,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
index dbf6501..009f229 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
@@ -2753,6 +2753,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
index 98f08a0..0e0b3df 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
@@ -2547,6 +2547,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/sh/be/libc.abilist b/sysdeps/unix/sysv/linux/sh/be/libc.abilist
index df11cc8..afb5bc3 100644
--- a/sysdeps/unix/sysv/linux/sh/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sh/be/libc.abilist
@@ -2608,6 +2608,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/sh/le/libc.abilist b/sysdeps/unix/sysv/linux/sh/le/libc.abilist
index 4ee5513..2b53a3c 100644
--- a/sysdeps/unix/sysv/linux/sh/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sh/le/libc.abilist
@@ -2605,6 +2605,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
index 3cefa76..43b9844 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
@@ -2748,6 +2748,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
index e3ea5c4..9ec4a0b 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
@@ -2574,6 +2574,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/tls-internal.c b/sysdeps/unix/sysv/linux/tls-internal.c
index 6e25b02..0326ebb 100644
--- a/sysdeps/unix/sysv/linux/tls-internal.c
+++ b/sysdeps/unix/sysv/linux/tls-internal.c
@@ -1 +1,38 @@
-/* Empty.  */
+/* Per-thread state.  Linux version.
+   Copyright (C) 2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <stdlib/arc4random.h>
+#include <string.h>
+#include <tls-internal.h>
+
+void
+__glibc_tls_internal_free (void)
+{
+  struct pthread *self = THREAD_SELF;
+  free (self->tls_state.strsignal_buf);
+  free (self->tls_state.strerror_l_buf);
+
+  if (self->tls_state.rand_state != NULL)
+    {
+      /* Clear any lingering random state prior so if the thread stack is
+         cached it won't leak any data.  */
+      explicit_bzero (self->tls_state.rand_state,
+		      sizeof (*self->tls_state.rand_state));
+      free (self->tls_state.rand_state);
+    }
+}
diff --git a/sysdeps/unix/sysv/linux/tls-internal.h b/sysdeps/unix/sysv/linux/tls-internal.h
index f7a1a62..ebc65d8 100644
--- a/sysdeps/unix/sysv/linux/tls-internal.h
+++ b/sysdeps/unix/sysv/linux/tls-internal.h
@@ -28,11 +28,7 @@ __glibc_tls_internal (void)
   return &THREAD_SELF->tls_state;
 }
 
-static inline void
-__glibc_tls_internal_free (void)
-{
-  free (THREAD_SELF->tls_state.strsignal_buf);
-  free (THREAD_SELF->tls_state.strerror_l_buf);
-}
+/* Reset the arc4random TCB state on fork.  */
+extern void __glibc_tls_internal_free (void) attribute_hidden;
 
 #endif
diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
index 2944bc7..367c8d0 100644
--- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
@@ -2525,6 +2525,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
index 4729619..6a614ef 100644
--- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
@@ -2631,6 +2631,9 @@ GLIBC_2.35 __memcmpeq F
 GLIBC_2.35 _dl_find_object F
 GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
+GLIBC_2.36 arc4random F
+GLIBC_2.36 arc4random_buf F
+GLIBC_2.36 arc4random_uniform F
 GLIBC_2.36 c8rtomb F
 GLIBC_2.36 fsconfig F
 GLIBC_2.36 fsmount F