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| author | Andy Lutomirski <luto@kernel.org> | 2019-12-23 00:20:46 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-06-22 14:11:03 +0200 |
| commit | 7f9f864af02180f130ed4c34eed14c642c26ea9b (patch) | |
| tree | ab4101b6c4c8a49a3e59cb479c07a15dfb3899e4 | |
| parent | 479d39707ff74ddf46de49b92ec997d0fd710b06 (diff) | |
| download | linux-stable-7f9f864af02180f130ed4c34eed14c642c26ea9b.tar.gz linux-stable-7f9f864af02180f130ed4c34eed14c642c26ea9b.tar.bz2 linux-stable-7f9f864af02180f130ed4c34eed14c642c26ea9b.zip | |
random: add GRND_INSECURE to return best-effort non-cryptographic bytes
commit 75551dbf112c992bc6c99a972990b3f272247e23 upstream.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/d5473b56cf1fa900ca4bd2b3fc1e5b8874399919.1577088521.git.luto@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/char/random.c | 11 | ||||
| -rw-r--r-- | include/uapi/linux/random.h | 2 |
2 files changed, 11 insertions, 2 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index 57bfd79868e9..8b061dfb1950 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -2217,7 +2217,14 @@ SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count, { int ret; - if (flags & ~(GRND_NONBLOCK|GRND_RANDOM)) + if (flags & ~(GRND_NONBLOCK|GRND_RANDOM|GRND_INSECURE)) + return -EINVAL; + + /* + * Requesting insecure and blocking randomness at the same time makes + * no sense. + */ + if ((flags & (GRND_INSECURE|GRND_RANDOM)) == (GRND_INSECURE|GRND_RANDOM)) return -EINVAL; if (count > INT_MAX) @@ -2226,7 +2233,7 @@ SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count, if (flags & GRND_RANDOM) return _random_read(flags & GRND_NONBLOCK, buf, count); - if (!crng_ready()) { + if (!(flags & GRND_INSECURE) && !crng_ready()) { if (flags & GRND_NONBLOCK) return -EAGAIN; ret = wait_for_random_bytes(); diff --git a/include/uapi/linux/random.h b/include/uapi/linux/random.h index 26ee91300e3e..c092d20088d3 100644 --- a/include/uapi/linux/random.h +++ b/include/uapi/linux/random.h @@ -49,8 +49,10 @@ struct rand_pool_info { * * GRND_NONBLOCK Don't block and return EAGAIN instead * GRND_RANDOM Use the /dev/random pool instead of /dev/urandom + * GRND_INSECURE Return non-cryptographic random bytes */ #define GRND_NONBLOCK 0x0001 #define GRND_RANDOM 0x0002 +#define GRND_INSECURE 0x0004 #endif /* _UAPI_LINUX_RANDOM_H */ |