[PATCH 4.9 056/264] random: ignore GRND_RANDOM in getentropy(2)

Greg Kroah-Hartman
2022-06-23T17:00:42Z

From: Andy Lutomirski <luto@kernel.org>

commit 48446f198f9adcb499b30332488dfd5bc3f176f6 upstream.

The separate blocking pool is going away. Start by ignoring
GRND_RANDOM in getentropy(2).

This should not materially break any API. Any code that worked
without this change should work at least as well with this change.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/705c5a091b63cc5da70c99304bb97e0109be0a26.1577088521.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>
---
drivers/char/random.c | 3 ---
include/uapi/linux/random.h | 2 +-
2 files changed, 1 insertion(+), 4 deletions(-)

--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -2200,9 +2200,6 @@ SYSCALL_DEFINE3(getrandom, char __user *
if (count > INT_MAX)
count = INT_MAX;

- if (flags & GRND_RANDOM)
- return _random_read(flags & GRND_NONBLOCK, buf, count);
-
if (!(flags & GRND_INSECURE) && !crng_ready()) {
if (flags & GRND_NONBLOCK)
return -EAGAIN;
--- a/include/uapi/linux/random.h
+++ b/include/uapi/linux/random.h
@@ -47,7 +47,7 @@ struct rand_pool_info {
* Flags for getrandom(2)
*
* GRND_NONBLOCK Don't block and return EAGAIN instead
- * GRND_RANDOM Use the /dev/random pool instead of /dev/urandom
+ * GRND_RANDOM No effect
* GRND_INSECURE Return non-cryptographic random bytes
*/
#define GRND_NONBLOCK 0x0001