[PATCH] vsock: use ns_capable_noaudit() on socket create

[PATCH] vsock: use ns_capable_noaudit() on socket create

[Jeff Vander Stoep]

During __vsock_create() CAP_NET_ADMIN is used to determine if the
vsock_sock->trusted should be set to true. This value is used later
for determing if a remote connection should be allowed to connect
to a restricted VM. Unfortunately, if the caller doesn't have
CAP_NET_ADMIN, an audit message such as an selinux denial is
generated even if the caller does not want a trusted socket.

Logging errors on success is confusing. To avoid this, switch the
capable(CAP_NET_ADMIN) check to the noaudit version.

Reported-by: Roman Kiryanov <rkir@google.com>
https://android-review.googlesource.com/c/device/generic/goldfish/+/1468545/
Signed-off-by: Jeff Vander Stoep <jeffv@google.com>
---
 net/vmw_vsock/af_vsock.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 9e93bc201cc0..b4d7b8aba003 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -739,7 +739,7 @@ static struct sock *__vsock_create(struct net *net,
 		vsk->buffer_min_size = psk->buffer_min_size;
 		vsk->buffer_max_size = psk->buffer_max_size;
 	} else {
-		vsk->trusted = capable(CAP_NET_ADMIN);
+		vsk->trusted = ns_capable_noaudit(&init_user_ns, CAP_NET_ADMIN);
 		vsk->owner = get_current_cred();
 		vsk->connect_timeout = VSOCK_DEFAULT_CONNECT_TIMEOUT;
 		vsk->buffer_size = VSOCK_DEFAULT_BUFFER_SIZE;
-- 
2.29.0.rc2.309.g374f81d7ae-goog

Re: [PATCH] vsock: use ns_capable_noaudit() on socket create

[James Morris]

On Fri, 23 Oct 2020, Jeff Vander Stoep wrote:

> During __vsock_create() CAP_NET_ADMIN is used to determine if the
> vsock_sock->trusted should be set to true. This value is used later
> for determing if a remote connection should be allowed to connect
> to a restricted VM. Unfortunately, if the caller doesn't have
> CAP_NET_ADMIN, an audit message such as an selinux denial is
> generated even if the caller does not want a trusted socket.
> 
> Logging errors on success is confusing. To avoid this, switch the
> capable(CAP_NET_ADMIN) check to the noaudit version.
> 
> Reported-by: Roman Kiryanov <rkir@google.com>
> https://android-review.googlesource.com/c/device/generic/goldfish/+/1468545/
> Signed-off-by: Jeff Vander Stoep <jeffv@google.com>


Reviewed-by: James Morris <jamorris@linux.microsoft.com>


-- 
James Morris
<jmorris@namei.org>

Re: [PATCH] vsock: use ns_capable_noaudit() on socket create

[Jakub Kicinski]

On Tue, 27 Oct 2020 07:37:37 +1100 (AEDT) James Morris wrote:
> On Fri, 23 Oct 2020, Jeff Vander Stoep wrote:
> 
> > During __vsock_create() CAP_NET_ADMIN is used to determine if the
> > vsock_sock->trusted should be set to true. This value is used later
> > for determing if a remote connection should be allowed to connect
> > to a restricted VM. Unfortunately, if the caller doesn't have
> > CAP_NET_ADMIN, an audit message such as an selinux denial is
> > generated even if the caller does not want a trusted socket.
> > 
> > Logging errors on success is confusing. To avoid this, switch the
> > capable(CAP_NET_ADMIN) check to the noaudit version.
> > 
> > Reported-by: Roman Kiryanov <rkir@google.com>
> > https://android-review.googlesource.com/c/device/generic/goldfish/+/1468545/
> > Signed-off-by: Jeff Vander Stoep <jeffv@google.com>  
> 
> Reviewed-by: James Morris <jamorris@linux.microsoft.com>

Applied to net, thanks!