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| author | Andy Lutomirski <luto@kernel.org> | 2019-12-23 09:20:46 +0100 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2020-01-07 22:07:00 +0100 |
| commit | 75551dbf112c992bc6c99a972990b3f272247e23 (patch) | |
| tree | 14f6622786b61f5e244eb9c0ec402e3d64cd8faa | |
| parent | random: Add a urandom_read_nowait() for random APIs that don't warn (diff) | |
| download | linux-75551dbf112c992bc6c99a972990b3f272247e23.tar.xz linux-75551dbf112c992bc6c99a972990b3f272247e23.zip | |
random: add GRND_INSECURE to return best-effort non-cryptographic bytes
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>
| -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 91954c0091a5..b7e2ad7eafca 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -2194,7 +2194,14 @@ 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) @@ -2203,7 +2210,7 @@ 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 */ |