diff options
| author | Adhemerval Zanella Netto <adhemerval.zanella@linaro.org> | 2022-07-21 10:04:59 -0300 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2022-07-22 11:58:27 -0300 |
| commit | 6f4e0fcfa2d2b0915816a3a3a1d48b4763a7dee2 (patch) | |
| tree | 6b1a61c1ccc7e265998db647729411dcb8826901 /sysdeps/unix/sysv/linux | |
| parent | 6c4ed247bf5aee6416c8c81a394cf692e068a579 (diff) | |
| download | glibc-6f4e0fcfa2d2b0915816a3a3a1d48b4763a7dee2.tar.xz glibc-6f4e0fcfa2d2b0915816a3a3a1d48b4763a7dee2.zip | |
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
Diffstat (limited to 'sysdeps/unix/sysv/linux')
36 files changed, 146 insertions, 7 deletions
diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist index 516b029d30..b66fadef40 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 dde08899fe..f918bb2d48 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 ade44d3029..093043a533 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 98b33708af..e0668a80cf 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 05dbbe5bcc..d28e7c60b7 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 430a24349e..922b05062f 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 de44616526..412144f94c 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 18b4fbf26e..134393900a 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 a8e959d417..02c65b6482 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 3a7e4ef6e4..0604029c68 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 864ad2cdf8..af2be5c80d 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 163058420d..e090b8d48f 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 a6debfda56..8c5b2db243 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 2b53d888de..68847134a2 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 849aae4130..daa44e64fa 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 37f6c1bf58..6169188c96 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 ff1eb91e10..2f7f1ccaf7 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 361b91f547..58e9b486b0 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 75b9e0ee1e..2c58d5ae2f 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 cb91606377..ffdb8819d5 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 G |