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ThreadRng::rng is unsafe #1037

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Merged
vks merged 1 commit into from
Sep 3, 2020
Merged

ThreadRng::rng is unsafe #1037

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27 changes: 16 additions & 11 deletions src/rngs/thread.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -95,30 +95,35 @@ impl Default for ThreadRng {
}
}

impl ThreadRng {
#[inline(always)]
fn rng(&mut self) -> &mut ReseedingRng<Core, OsRng> {
unsafe { &mut *self.rng.get() }
}
}

impl RngCore for ThreadRng {
#[inline(always)]
fn next_u32(&mut self) -> u32 {
self.rng().next_u32()
// SAFETY: We must make sure to stop using `rng` before anyone else
// creates another mutable reference
let rng = unsafe { &mut *self.rng.get() };
rng.next_u32()
}

#[inline(always)]
fn next_u64(&mut self) -> u64 {
self.rng().next_u64()
// SAFETY: We must make sure to stop using `rng` before anyone else
// creates another mutable reference
let rng = unsafe { &mut *self.rng.get() };
rng.next_u64()
}

fn fill_bytes(&mut self, dest: &mut [u8]) {
self.rng().fill_bytes(dest)
// SAFETY: We must make sure to stop using `rng` before anyone else
// creates another mutable reference
let rng = unsafe { &mut *self.rng.get() };
rng.fill_bytes(dest)
}

fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
self.rng().try_fill_bytes(dest)
// SAFETY: We must make sure to stop using `rng` before anyone else
// creates another mutable reference
let rng = unsafe { &mut *self.rng.get() };
rng.try_fill_bytes(dest)
}
}

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