From: "Jason A. Donenfeld" <Jason@zx2c4.com>

Date: Sun, 4 Feb 2018 23:07:46 +0100

Subject: random: always fill buffer in get_random_bytes_wait

Git-commit: 25e3fca492035a2e1d4ac6e3b1edd9c1acd48897

Patch-mainline: v4.17-rc1

References: git-fixes

In the unfortunate event that a developer fails to check the return

value of get_random_bytes_wait, or simply wants to make a "best effort"

attempt, for whatever that's worth, it's much better to still fill the

buffer with _something_ rather than catastrophically failing in the case

of an interruption. This is both a defense in depth measure against

inevitable programming bugs, as well as a means of making the API a bit

more useful.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Acked-by: Lee Duncan <lduncan@suse.com>

---

 include/linux/random.h | 4 +---

 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/include/linux/random.h b/include/linux/random.h

index 4024f7d9c77d..2ddf13b4281e 100644

--- a/include/linux/random.h

+++ b/include/linux/random.h

@@ -85,10 +85,8 @@ static inline unsigned long get_random_canary(void)

 static inline int get_random_bytes_wait(void *buf, int nbytes)

 {

 	int ret = wait_for_random_bytes();

-	if (unlikely(ret))

-		return ret;

 	get_random_bytes(buf, nbytes);

-	return 0;

+	return ret;

 }

 #define declare_get_random_var_wait(var) \