diff options
| -rw-r--r-- | Cargo.lock | 4 | ||||
| -rw-r--r-- | library/std/Cargo.toml | 2 | ||||
| -rw-r--r-- | library/std/src/sys/unix/rand.rs | 15 |
3 files changed, 18 insertions, 3 deletions
diff --git a/Cargo.lock b/Cargo.lock index 2f143b097b7..21902888e88 100644 --- a/Cargo.lock +++ b/Cargo.lock @@ -2064,9 +2064,9 @@ checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55" [[package]] name = "libc" -version = "0.2.125" +version = "0.2.126" source = "registry+https://github.com/rust-lang/crates.io-index" -checksum = "5916d2ae698f6de9bfb891ad7a8d65c09d232dc58cc4ac433c7da3b2fd84bc2b" +checksum = "349d5a591cd28b49e1d1037471617a32ddcda5731b99419008085f72d5a53836" dependencies = [ "rustc-std-workspace-core", ] diff --git a/library/std/Cargo.toml b/library/std/Cargo.toml index d0d7d480fe8..95506fc1eb9 100644 --- a/library/std/Cargo.toml +++ b/library/std/Cargo.toml @@ -15,7 +15,7 @@ cfg-if = { version = "0.1.8", features = ['rustc-dep-of-std'] } panic_unwind = { path = "../panic_unwind", optional = true } panic_abort = { path = "../panic_abort" } core = { path = "../core" } -libc = { version = "0.2.125", default-features = false, features = ['rustc-dep-of-std'] } +libc = { version = "0.2.126", default-features = false, features = ['rustc-dep-of-std'] } compiler_builtins = { version = "0.1.71" } profiler_builtins = { path = "../profiler_builtins", optional = true } unwind = { path = "../unwind" } diff --git a/library/std/src/sys/unix/rand.rs b/library/std/src/sys/unix/rand.rs index 17e8efbe097..ea6df724713 100644 --- a/library/std/src/sys/unix/rand.rs +++ b/library/std/src/sys/unix/rand.rs @@ -30,6 +30,9 @@ mod imp { #[cfg(any(target_os = "linux", target_os = "android"))] fn getrandom(buf: &mut [u8]) -> libc::ssize_t { + use crate::sync::atomic::{AtomicBool, Ordering}; + use crate::sys::os::errno; + // A weak symbol allows interposition, e.g. for perf measurements that want to // disable randomness for consistency. Otherwise, we'll try a raw syscall. // (`getrandom` was added in glibc 2.25, musl 1.1.20, android API level 28) @@ -41,6 +44,18 @@ mod imp { ) -> libc::ssize_t } + // This provides the best quality random numbers available at the given moment + // without ever blocking, and is preferable to falling back to /dev/urandom. + static GRND_INSECURE_AVAILABLE: AtomicBool = AtomicBool::new(true); + if GRND_INSECURE_AVAILABLE.load(Ordering::Relaxed) { + let ret = unsafe { getrandom(buf.as_mut_ptr().cast(), buf.len(), libc::GRND_INSECURE) }; + if ret == -1 && errno() as libc::c_int == libc::EINVAL { + GRND_INSECURE_AVAILABLE.store(false, Ordering::Relaxed); + } else { + return ret; + } + } + unsafe { getrandom(buf.as_mut_ptr().cast(), buf.len(), libc::GRND_NONBLOCK) } } |