virtio: rng: add derating factor for use by hwrng core
Subsystems (2)
PATCH 1/1 virtio: rng: add derating factor for use by hwrng core
The khwrngd thread is started when a hwrng device of sufficient quality is registered. The virtio-rng device is backed by the hypervisor, and we trust the hypervisor to provide real entropy.
A malicious hypervisor is a scenario that's irrelevant -- such a setup is bound to cause all sorts of badness, and a compromised hwrng is not the biggest threat.
Given this, we are certain the quality of randomness we receive is perfectly trustworthy. Hence, we use 100% for the factor, indicating maximum confidence in the source.
---
Pretty small and contained patch; would be great if it is picked up for 3.17.
v2: re-word commit msg
[Agreed, re-sending to Linus with SOB before jumping on plane]
--- drivers/char/hw_random/virtio-rng.c | 1 + 1 file changed, 1 insertion(+)
(quoted diff) +0 -0
b/drivers/char/hw_random/virtio-rng.c
index 0027137..2e3139e 100644
drivers/char/hw_random/virtio-rng.c +0 -0
@@ -116,6 +116,7 @@ static int probe_common(struct virtio_device *vdev)
.cleanup = virtio_cleanup,
.priv = (unsigned long)vi,
.name = vi->name,
+ .quality = 1000,
}; vdev->priv = vi;
Quoted 14 lines · Rusty Russell
The khwrngd thread is started when a hwrng device of sufficient quality is registered. The virtio-rng device is backed by the hypervisor, and we trust the hypervisor to provide real entropy.
A malicious hypervisor is a scenario that's irrelevant -- such a setup is bound to cause all sorts of badness, and a compromised hwrng is not the biggest threat.
Given this, we are certain the quality of randomness we receive is perfectly trustworthy. Hence, we use 100% for the factor, indicating maximum confidence in the source.
Signed-off-by Amit Shah <[email protected]>Signed-off-by Rusty Russell <[email protected]>
Quoted 7 lines
---
Pretty small and contained patch; would be great if it is picked up for 3.17.v2: re-word commit msg
[Agreed, re-sending to Linus with SOB before jumping on plane]
Quoted 7 lines · Rusty Russell
The khwrngd thread is started when a hwrng device of sufficient quality is registered. The virtio-rng device is backed by the hypervisor, and we trust the hypervisor to provide real entropy.
A malicious hypervisor is a scenario that's irrelevant -- such a setup is bound to cause all sorts of badness, and a compromised hwrng is not the biggest threat.
s/malicious/malicious or badly implemented/
s/is not the biggest threat/is the least of the user's worries/
Quoted 3 lines
Given this, we are certain the quality of randomness we receive is perfectly trustworthy. Hence, we use 100% for the factor, indicating maximum confidence in the source.
s/we are certain/we might as well assume that/
I won't insist on the wording changes, but I think it's a better way of phrasing things.
Cheers,
- Ted
Quoted 8 lines · Rusty Russell
The khwrngd thread is started when a hwrng device of sufficient quality is registered. The virtio-rng device is backed by the hypervisor, and we trust the hypervisor to provide real entropy.
A malicious hypervisor is a scenario that's irrelevant -- such a setup is bound to cause all sorts of badness, and a compromised hwrng is not the biggest threat.
Quoted 6 lines
Given this, we are certain the quality of randomness we receive is perfectly trustworthy. Hence, we use 100% for the factor, indicating maximum confidence in the source.
Signed-off-by Amit Shah <[email protected]>Signed-off-by Rusty Russell <[email protected]>
Quoted 29 lines
---
Pretty small and contained patch; would be great if it is picked up for 3.17.v2: re-word commit msg
[Agreed, re-sending to Linus with SOB before jumping on plane]
--- drivers/char/hw_random/virtio-rng.c | 1 + 1 file changed, 1 insertion(+)drivers/char/hw_random/virtio-rng.c +1
-1@@ -116,6 +116,7 @@ static int probe_common(struct virtio_device *vdev) .cleanup = virtio_cleanup, .priv = (unsigned long)vi, .name = vi->name, + .quality = 1000, }; vdev->priv = vi; --To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected]
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Signature · 1 line
Amos.