* Re: [PATCH] vhost/vsock: fix vhost vsock cid hashing inconsistent
2019-01-08 8:07 [PATCH] vhost/vsock: fix vhost vsock cid hashing inconsistent Zha Bin
@ 2019-01-08 11:24 ` Stefan Hajnoczi
2019-01-09 8:21 ` Christian Borntraeger
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Stefan Hajnoczi @ 2019-01-08 11:24 UTC (permalink / raw)
To: Zha Bin
Cc: stefanha, mst, jasowang, kvm, virtualization, netdev,
linux-kernel, gerry, kata-dev
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On Tue, Jan 08, 2019 at 04:07:03PM +0800, Zha Bin wrote:
> The vsock core only supports 32bit CID, but the Virtio-vsock spec define
> CID (dst_cid and src_cid) as u64 and the upper 32bits is reserved as
> zero. This inconsistency causes one bug in vhost vsock driver. The
> scenarios is:
>
> 0. A hash table (vhost_vsock_hash) is used to map an CID to a vsock
> object. And hash_min() is used to compute the hash key. hash_min() is
> defined as:
> (sizeof(val) <= 4 ? hash_32(val, bits) : hash_long(val, bits)).
> That means the hash algorithm has dependency on the size of macro
> argument 'val'.
> 0. In function vhost_vsock_set_cid(), a 64bit CID is passed to
> hash_min() to compute the hash key when inserting a vsock object into
> the hash table.
> 0. In function vhost_vsock_get(), a 32bit CID is passed to hash_min()
> to compute the hash key when looking up a vsock for an CID.
>
> Because the different size of the CID, hash_min() returns different hash
> key, thus fails to look up the vsock object for an CID.
>
> To fix this bug, we keep CID as u64 in the IOCTLs and virtio message
> headers, but explicitly convert u64 to u32 when deal with the hash table
> and vsock core.
>
> Fixes: 834e772c8db0 ("vhost/vsock: fix use-after-free in network stack callers")
> Link: https://github.com/stefanha/virtio/blob/vsock/trunk/content.tex
> Signed-off-by: Zha Bin <zhabin@linux.alibaba.com>
> Reviewed-by: Liu Jiang <gerry@linux.alibaba.com>
> ---
> drivers/vhost/vsock.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Thanks for tracking this down!
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] vhost/vsock: fix vhost vsock cid hashing inconsistent
2019-01-08 8:07 [PATCH] vhost/vsock: fix vhost vsock cid hashing inconsistent Zha Bin
2019-01-08 11:24 ` Stefan Hajnoczi
@ 2019-01-09 8:21 ` Christian Borntraeger
2019-01-11 4:13 ` Jason Wang
2019-01-12 1:48 ` David Miller
3 siblings, 0 replies; 5+ messages in thread
From: Christian Borntraeger @ 2019-01-09 8:21 UTC (permalink / raw)
To: Zha Bin, stefanha
Cc: mst, jasowang, kvm, virtualization, netdev, linux-kernel, gerry,
kata-dev, Peter Morjan
Adding Peter,
is this the same problem that you reported me today?
Can you test Zha Bins patch?
Christian
On 08.01.2019 09:07, Zha Bin wrote:
> The vsock core only supports 32bit CID, but the Virtio-vsock spec define
> CID (dst_cid and src_cid) as u64 and the upper 32bits is reserved as
> zero. This inconsistency causes one bug in vhost vsock driver. The
> scenarios is:
>
> 0. A hash table (vhost_vsock_hash) is used to map an CID to a vsock
> object. And hash_min() is used to compute the hash key. hash_min() is
> defined as:
> (sizeof(val) <= 4 ? hash_32(val, bits) : hash_long(val, bits)).
> That means the hash algorithm has dependency on the size of macro
> argument 'val'.
> 0. In function vhost_vsock_set_cid(), a 64bit CID is passed to
> hash_min() to compute the hash key when inserting a vsock object into
> the hash table.
> 0. In function vhost_vsock_get(), a 32bit CID is passed to hash_min()
> to compute the hash key when looking up a vsock for an CID.
>
> Because the different size of the CID, hash_min() returns different hash
> key, thus fails to look up the vsock object for an CID.
>
> To fix this bug, we keep CID as u64 in the IOCTLs and virtio message
> headers, but explicitly convert u64 to u32 when deal with the hash table
> and vsock core.
>
> Fixes: 834e772c8db0 ("vhost/vsock: fix use-after-free in network stack callers")
> Link: https://github.com/stefanha/virtio/blob/vsock/trunk/content.tex
> Signed-off-by: Zha Bin <zhabin@linux.alibaba.com>
> Reviewed-by: Liu Jiang <gerry@linux.alibaba.com>
> ---
> drivers/vhost/vsock.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
> index bc42d38ae031..3fbc068eaa9b 100644
> --- a/drivers/vhost/vsock.c
> +++ b/drivers/vhost/vsock.c
> @@ -642,7 +642,7 @@ static int vhost_vsock_set_cid(struct vhost_vsock *vsock, u64 guest_cid)
> hash_del_rcu(&vsock->hash);
>
> vsock->guest_cid = guest_cid;
> - hash_add_rcu(vhost_vsock_hash, &vsock->hash, guest_cid);
> + hash_add_rcu(vhost_vsock_hash, &vsock->hash, vsock->guest_cid);
> mutex_unlock(&vhost_vsock_mutex);
>
> return 0;
>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] vhost/vsock: fix vhost vsock cid hashing inconsistent
2019-01-08 8:07 [PATCH] vhost/vsock: fix vhost vsock cid hashing inconsistent Zha Bin
2019-01-08 11:24 ` Stefan Hajnoczi
2019-01-09 8:21 ` Christian Borntraeger
@ 2019-01-11 4:13 ` Jason Wang
2019-01-12 1:48 ` David Miller
3 siblings, 0 replies; 5+ messages in thread
From: Jason Wang @ 2019-01-11 4:13 UTC (permalink / raw)
To: Zha Bin, stefanha
Cc: mst, kvm, virtualization, netdev, linux-kernel, gerry, kata-dev
On 2019/1/8 下午4:07, Zha Bin wrote:
> The vsock core only supports 32bit CID, but the Virtio-vsock spec define
> CID (dst_cid and src_cid) as u64 and the upper 32bits is reserved as
> zero. This inconsistency causes one bug in vhost vsock driver. The
> scenarios is:
>
> 0. A hash table (vhost_vsock_hash) is used to map an CID to a vsock
> object. And hash_min() is used to compute the hash key. hash_min() is
> defined as:
> (sizeof(val) <= 4 ? hash_32(val, bits) : hash_long(val, bits)).
> That means the hash algorithm has dependency on the size of macro
> argument 'val'.
> 0. In function vhost_vsock_set_cid(), a 64bit CID is passed to
> hash_min() to compute the hash key when inserting a vsock object into
> the hash table.
> 0. In function vhost_vsock_get(), a 32bit CID is passed to hash_min()
> to compute the hash key when looking up a vsock for an CID.
>
> Because the different size of the CID, hash_min() returns different hash
> key, thus fails to look up the vsock object for an CID.
>
> To fix this bug, we keep CID as u64 in the IOCTLs and virtio message
> headers, but explicitly convert u64 to u32 when deal with the hash table
> and vsock core.
>
> Fixes: 834e772c8db0 ("vhost/vsock: fix use-after-free in network stack callers")
> Link: https://github.com/stefanha/virtio/blob/vsock/trunk/content.tex
> Signed-off-by: Zha Bin <zhabin@linux.alibaba.com>
> Reviewed-by: Liu Jiang <gerry@linux.alibaba.com>
> ---
> drivers/vhost/vsock.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
> index bc42d38ae031..3fbc068eaa9b 100644
> --- a/drivers/vhost/vsock.c
> +++ b/drivers/vhost/vsock.c
> @@ -642,7 +642,7 @@ static int vhost_vsock_set_cid(struct vhost_vsock *vsock, u64 guest_cid)
> hash_del_rcu(&vsock->hash);
>
> vsock->guest_cid = guest_cid;
> - hash_add_rcu(vhost_vsock_hash, &vsock->hash, guest_cid);
> + hash_add_rcu(vhost_vsock_hash, &vsock->hash, vsock->guest_cid);
> mutex_unlock(&vhost_vsock_mutex);
>
> return 0;
Acked-by: Jason Wang <jasowang@redhat.com>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] vhost/vsock: fix vhost vsock cid hashing inconsistent
2019-01-08 8:07 [PATCH] vhost/vsock: fix vhost vsock cid hashing inconsistent Zha Bin
` (2 preceding siblings ...)
2019-01-11 4:13 ` Jason Wang
@ 2019-01-12 1:48 ` David Miller
3 siblings, 0 replies; 5+ messages in thread
From: David Miller @ 2019-01-12 1:48 UTC (permalink / raw)
To: zhabin
Cc: stefanha, mst, jasowang, kvm, virtualization, netdev,
linux-kernel, gerry, kata-dev
From: Zha Bin <zhabin@linux.alibaba.com>
Date: Tue, 8 Jan 2019 16:07:03 +0800
> The vsock core only supports 32bit CID, but the Virtio-vsock spec define
> CID (dst_cid and src_cid) as u64 and the upper 32bits is reserved as
> zero. This inconsistency causes one bug in vhost vsock driver. The
> scenarios is:
>
> 0. A hash table (vhost_vsock_hash) is used to map an CID to a vsock
> object. And hash_min() is used to compute the hash key. hash_min() is
> defined as:
> (sizeof(val) <= 4 ? hash_32(val, bits) : hash_long(val, bits)).
> That means the hash algorithm has dependency on the size of macro
> argument 'val'.
> 0. In function vhost_vsock_set_cid(), a 64bit CID is passed to
> hash_min() to compute the hash key when inserting a vsock object into
> the hash table.
> 0. In function vhost_vsock_get(), a 32bit CID is passed to hash_min()
> to compute the hash key when looking up a vsock for an CID.
>
> Because the different size of the CID, hash_min() returns different hash
> key, thus fails to look up the vsock object for an CID.
>
> To fix this bug, we keep CID as u64 in the IOCTLs and virtio message
> headers, but explicitly convert u64 to u32 when deal with the hash table
> and vsock core.
>
> Fixes: 834e772c8db0 ("vhost/vsock: fix use-after-free in network stack callers")
> Link: https://github.com/stefanha/virtio/blob/vsock/trunk/content.tex
> Signed-off-by: Zha Bin <zhabin@linux.alibaba.com>
> Reviewed-by: Liu Jiang <gerry@linux.alibaba.com>
Applied, thank you.
^ permalink raw reply [flat|nested] 5+ messages in thread