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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Andy Lutomirski <luto@kernel.org>,
        Theodore Tso <tytso@mit.edu>,
        "Jason A. Donenfeld" <Jason@zx2c4.com>
Subject: [PATCH 4.9 056/264] random: ignore GRND_RANDOM in getentropy(2)
Date:   Thu, 23 Jun 2022 18:40:49 +0200
Message-Id: <20220623164345.658306748@linuxfoundation.org>
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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