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| author | Jason A. Donenfeld <Jason@zx2c4.com> | 2024-08-27 17:14:18 +0200 |
|---|---|---|
| committer | Jason A. Donenfeld <Jason@zx2c4.com> | 2024-09-13 17:28:35 +0200 |
| commit | 6fd13b282f62bd840f2410692deaa23a42fd91fa (patch) | |
| tree | 14674818fd45938409c5b6f95158f0b8c2415abd /include/vdso | |
| parent | 2aec90036dcd2cb7047a6e28625fba6c64756665 (diff) | |
| download | linux-6fd13b282f62bd840f2410692deaa23a42fd91fa.tar.gz linux-6fd13b282f62bd840f2410692deaa23a42fd91fa.tar.bz2 linux-6fd13b282f62bd840f2410692deaa23a42fd91fa.zip | |
random: vDSO: move prototype of arch chacha function to vdso/getrandom.h
Having the prototype for __arch_chacha20_blocks_nostack in
arch/x86/include/asm/vdso/getrandom.h meant that the prototype and large
doc comment were cloned by every architecture, which has been causing
unnecessary churn. Instead move it into include/vdso/getrandom.h, where
it can be shared by all archs implementing it.
As a side bonus, this then lets us use that prototype in the
vdso_test_chacha self test, to ensure that it matches the source, and
indeed doing so turned up some inconsistencies, which are rectified
here.
Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Diffstat (limited to 'include/vdso')
| -rw-r--r-- | include/vdso/getrandom.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/include/vdso/getrandom.h b/include/vdso/getrandom.h index a8b7c14b0ae0..4cf02e678f5e 100644 --- a/include/vdso/getrandom.h +++ b/include/vdso/getrandom.h @@ -43,4 +43,17 @@ struct vgetrandom_state { bool in_use; }; +/** + * __arch_chacha20_blocks_nostack - Generate ChaCha20 stream without using the stack. + * @dst_bytes: Destination buffer to hold @nblocks * 64 bytes of output. + * @key: 32-byte input key. + * @counter: 8-byte counter, read on input and updated on return. + * @nblocks: Number of blocks to generate. + * + * Generates a given positive number of blocks of ChaCha20 output with nonce=0, and does not write + * to any stack or memory outside of the parameters passed to it, in order to mitigate stack data + * leaking into forked child processes. + */ +extern void __arch_chacha20_blocks_nostack(u8 *dst_bytes, const u32 *key, u32 *counter, size_t nblocks); + #endif /* _VDSO_GETRANDOM_H */ |