Re: [RFC][PATCH] RANDOM: ATH9K RNG delivers zero bits of entropy
From: Jason Cooper <hidden>
Date: 2016-08-06 20:02:00
Also in:
linux-crypto, lkml
Hi Stephan, On Fri, Aug 05, 2016 at 05:08:14PM +0200, Stephan Mueller wrote:
Hi Ted, Herbert, I sent a question to the ATH9K RNG some time ago to the developers. See https://www.mail-archive.com/linux-crypto@vger.kernel.org/msg19115.html I have not yet received a word and I think this issue should be resolved. Thanks Stephan ---8<---
If the above text is placed below the three dashes, "---", below ...
The ATH9K driver implements an RNG which is completely bypassing the standard Linux HW generator logic. The RNG may or may not deliver entropy. Considering the conservative approach in treating entropy with respect to non-auditable sources, this patch changes the delivered entropy value to zero. The RNG still feeds data into the input_pool but it is assumed to have no entropy. When the ATH9K RNG changes to use the HW RNG framework, it may re-enable the entropy estimation considering that a user can change that value at boot and runtime. Signed-off-by: Stephan Mueller <redacted> ---
here, then the mail can be applied directly without editing.
quoted hunk ↗ jump to hunk
drivers/net/wireless/ath/ath9k/rng.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)diff --git a/drivers/net/wireless/ath/ath9k/rng.c b/drivers/net/wireless/ath/ath9k/rng.c index d38e50f..d63dc48 100644 --- a/drivers/net/wireless/ath/ath9k/rng.c +++ b/drivers/net/wireless/ath/ath9k/rng.c@@ -92,8 +92,7 @@ static int ath9k_rng_kthread(void *data) fail_stats = 0; /* sleep until entropy bits under write_wakeup_threshold */ - add_hwgenerator_randomness((void *)rng_buf, bytes_read, - ATH9K_RNG_ENTROPY(bytes_read));
This is the only use of this macro. I'd remove the #define on line 25 as well.
+ add_hwgenerator_randomness((void *)rng_buf, bytes_read, 0); } kfree(rng_buf);
Other than that, Reviewed-by: Jason Cooper <redacted> thx, Jason.