* [cip-dev] [PATCH 4.4] vhost: Check docket sk_family instead of call getname
@ 2020-03-27 7:57 Pavel Machek
2020-03-30 4:38 ` Punit Agrawal
0 siblings, 1 reply; 2+ messages in thread
From: Pavel Machek @ 2020-03-27 7:57 UTC (permalink / raw)
To: cip-dev, stable, eperezma, mst, davem
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From: Eugenio Pérez <eperezma@redhat.com>
Doing so, we save one call to get data we already have in the struct.
Also, since there is no guarantee that getname use sockaddr_ll
parameter beyond its size, we add a little bit of security here.
It should do not do beyond MAX_ADDR_LEN, but syzbot found that
ax25_getname writes more (72 bytes, the size of full_sockaddr_ax25,
versus 20 + 32 bytes of sockaddr_ll + MAX_ADDR_LEN in syzbot repro).
Fixes: 3a4d5c94e9593 ("vhost_net: a kernel-level virtio server")
Reported-by: syzbot+f2a62d07a5198c819c7b@syzkaller.appspotmail.com
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Upstream: 42d84c8490f9f0931786f1623191fcab397c3d64
Signed-off-by: Pavel Machek <pavel@denx.de>
---
drivers/vhost/net.c | 13 ++-----------
1 file changed, 2 insertions(+), 11 deletions(-)
---
Since it is a security problem, I backported the patch to 4.4. I
compile tested it on cip test farm, but it was only built for single
target, probably due to too big config.
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 1459dc9fd701..5efac33c29dc 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -815,11 +815,7 @@ static int vhost_net_release(struct inode *inode, struct file *f)
static struct socket *get_raw_socket(int fd)
{
- struct {
- struct sockaddr_ll sa;
- char buf[MAX_ADDR_LEN];
- } uaddr;
- int uaddr_len = sizeof uaddr, r;
+ int r;
struct socket *sock = sockfd_lookup(fd, &r);
if (!sock)
@@ -831,12 +827,7 @@ static struct socket *get_raw_socket(int fd)
goto err;
}
- r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa,
- &uaddr_len, 0);
- if (r)
- goto err;
-
- if (uaddr.sa.sll_family != AF_PACKET) {
+ if (sock->sk->sk_family != AF_PACKET) {
r = -EPFNOSUPPORT;
goto err;
}
--
2.20.1
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [cip-dev] [PATCH 4.4] vhost: Check docket sk_family instead of call getname
2020-03-27 7:57 [cip-dev] [PATCH 4.4] vhost: Check docket sk_family instead of call getname Pavel Machek
@ 2020-03-30 4:38 ` Punit Agrawal
0 siblings, 0 replies; 2+ messages in thread
From: Punit Agrawal @ 2020-03-30 4:38 UTC (permalink / raw)
To: Pavel Machek; +Cc: eperezma, davem, stable, cip-dev, mst
Hi Pavel,
A couple of comments below -
Pavel Machek <pavel@ucw.cz> writes:
> From: Eugenio Pérez <eperezma@redhat.com>
>
> Doing so, we save one call to get data we already have in the struct.
>
> Also, since there is no guarantee that getname use sockaddr_ll
> parameter beyond its size, we add a little bit of security here.
> It should do not do beyond MAX_ADDR_LEN, but syzbot found that
> ax25_getname writes more (72 bytes, the size of full_sockaddr_ax25,
> versus 20 + 32 bytes of sockaddr_ll + MAX_ADDR_LEN in syzbot repro).
>
> Fixes: 3a4d5c94e9593 ("vhost_net: a kernel-level virtio server")
> Reported-by: syzbot+f2a62d07a5198c819c7b@syzkaller.appspotmail.com
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
> Acked-by: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
> Upstream: 42d84c8490f9f0931786f1623191fcab397c3d64
Please follow the style guidelines documented in
Documentation/process/stable-kernel-rules.rst. In this instance, please
mention the upstream commit id following -
The upstream commit ID must be specified with a separate line above the
commit
text, like this:
commit <sha1> upstream.
For an example, take a look at Commit ad598a48fe61 ("vhost: Check docket
sk_family instead of call getname"). It's a backport of the same
upstream patch to 4.19 stable kernel.
> Signed-off-by: Pavel Machek <pavel@denx.de>
> ---
> drivers/vhost/net.c | 13 ++-----------
> 1 file changed, 2 insertions(+), 11 deletions(-)
>
> ---
>
> Since it is a security problem, I backported the patch to 4.4. I
> compile tested it on cip test farm, but it was only built for single
> target, probably due to too big config.
>
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 1459dc9fd701..5efac33c29dc 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -815,11 +815,7 @@ static int vhost_net_release(struct inode *inode, struct file *f)
>
> static struct socket *get_raw_socket(int fd)
> {
> - struct {
> - struct sockaddr_ll sa;
> - char buf[MAX_ADDR_LEN];
> - } uaddr;
> - int uaddr_len = sizeof uaddr, r;
> + int r;
> struct socket *sock = sockfd_lookup(fd, &r);
>
> if (!sock)
> @@ -831,12 +827,7 @@ static struct socket *get_raw_socket(int fd)
> goto err;
> }
>
> - r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa,
> - &uaddr_len, 0);
> - if (r)
> - goto err;
> -
> - if (uaddr.sa.sll_family != AF_PACKET) {
> + if (sock->sk->sk_family != AF_PACKET) {
> r = -EPFNOSUPPORT;
> goto err;
> }
> --
> 2.20.1
This patch fails to apply with the following error -
% git am vhost.mbox
Applying: vhost: Check docket sk_family instead of call getname
error: corrupt patch at line 16
Patch failed at 0001 vhost: Check docket sk_family instead of call
getname
hint: Use 'git am --show-current-patch' to see the failed patch
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".
There is some encoding issue in your mail client. The same workflow
works for other kernel patches.
Thanks,
Punit
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cip-dev@lists.cip-project.org
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