* [PATCH] ipx: call ipxitf_put() in ioctl error path
[not found] <143C0AFC63FC204CB0C55BB88F3A8ABB33419ED1@EX02.corp.qihoo.net>
@ 2017-05-02 10:58 ` Dan Carpenter
2017-05-02 19:35 ` David Miller
2017-05-02 23:42 ` [kernel-hardening] " Kees Cook
0 siblings, 2 replies; 4+ messages in thread
From: Dan Carpenter @ 2017-05-02 10:58 UTC (permalink / raw)
To: David S. Miller; +Cc: netdev, security, secalert
We should call ipxitf_put() if the copy_to_user() fails.
Reported-by: 李强 <liqiang6-s@360.cn>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
diff --git a/net/ipx/af_ipx.c b/net/ipx/af_ipx.c
index 8a9219ff2e77..fa31ef29e3fa 100644
--- a/net/ipx/af_ipx.c
+++ b/net/ipx/af_ipx.c
@@ -1168,11 +1168,10 @@ static int ipxitf_ioctl(unsigned int cmd, void __user *arg)
sipx->sipx_network = ipxif->if_netnum;
memcpy(sipx->sipx_node, ipxif->if_node,
sizeof(sipx->sipx_node));
- rc = -EFAULT;
+ rc = 0;
if (copy_to_user(arg, &ifr, sizeof(ifr)))
- break;
+ rc = -EFAULT;
ipxitf_put(ipxif);
- rc = 0;
break;
}
case SIOCAIPXITFCRT:
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] ipx: call ipxitf_put() in ioctl error path
2017-05-02 10:58 ` [PATCH] ipx: call ipxitf_put() in ioctl error path Dan Carpenter
@ 2017-05-02 19:35 ` David Miller
2017-05-02 23:42 ` [kernel-hardening] " Kees Cook
1 sibling, 0 replies; 4+ messages in thread
From: David Miller @ 2017-05-02 19:35 UTC (permalink / raw)
To: dan.carpenter; +Cc: netdev, security, secalert
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Tue, 2 May 2017 13:58:53 +0300
> We should call ipxitf_put() if the copy_to_user() fails.
>
> Reported-by: 李强 <liqiang6-s@360.cn>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Applied, thanks Dan.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] ipx: call ipxitf_put() in ioctl error path
2017-05-02 10:58 ` [PATCH] ipx: call ipxitf_put() in ioctl error path Dan Carpenter
@ 2017-05-02 23:42 ` Kees Cook
2017-05-02 23:42 ` [kernel-hardening] " Kees Cook
1 sibling, 0 replies; 4+ messages in thread
From: Kees Cook @ 2017-05-02 23:42 UTC (permalink / raw)
To: Dan Carpenter, kernel-hardening
Cc: David S. Miller, Network Development, security, secalert
On Tue, May 2, 2017 at 3:58 AM, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> We should call ipxitf_put() if the copy_to_user() fails.
>
> Reported-by: 李强 <liqiang6-s@360.cn>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> diff --git a/net/ipx/af_ipx.c b/net/ipx/af_ipx.c
> index 8a9219ff2e77..fa31ef29e3fa 100644
> --- a/net/ipx/af_ipx.c
> +++ b/net/ipx/af_ipx.c
> @@ -1168,11 +1168,10 @@ static int ipxitf_ioctl(unsigned int cmd, void __user *arg)
> sipx->sipx_network = ipxif->if_netnum;
> memcpy(sipx->sipx_node, ipxif->if_node,
> sizeof(sipx->sipx_node));
> - rc = -EFAULT;
> + rc = 0;
> if (copy_to_user(arg, &ifr, sizeof(ifr)))
> - break;
> + rc = -EFAULT;
> ipxitf_put(ipxif);
> - rc = 0;
> break;
> }
> case SIOCAIPXITFCRT:
This refcount overflow flaw (and resulting use-after-free) appears to
be reachable from unprivileged userspace, though I think it requires
an interface already be configured, so this is likely not much risk to
most users. Someone more familiar with IPX should double-check...
And, of course, I should point out this flaw would have been blocked
entirely by using refcount_t:
https://lkml.org/lkml/2017/3/17/193
And if it didn't require a configured interface, it would be mitigated
with module autoload blocking:
https://lkml.org/lkml/2017/4/19/1088
(Yes, yes, I know both are still being worked on, but this is a good
example to show another case where they'd have been useful.)
-Kees
--
Kees Cook
Pixel Security
^ permalink raw reply [flat|nested] 4+ messages in thread
* [kernel-hardening] Re: [PATCH] ipx: call ipxitf_put() in ioctl error path
@ 2017-05-02 23:42 ` Kees Cook
0 siblings, 0 replies; 4+ messages in thread
From: Kees Cook @ 2017-05-02 23:42 UTC (permalink / raw)
To: Dan Carpenter, kernel-hardening
Cc: David S. Miller, Network Development, security, secalert
On Tue, May 2, 2017 at 3:58 AM, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> We should call ipxitf_put() if the copy_to_user() fails.
>
> Reported-by: 李强 <liqiang6-s@360.cn>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> diff --git a/net/ipx/af_ipx.c b/net/ipx/af_ipx.c
> index 8a9219ff2e77..fa31ef29e3fa 100644
> --- a/net/ipx/af_ipx.c
> +++ b/net/ipx/af_ipx.c
> @@ -1168,11 +1168,10 @@ static int ipxitf_ioctl(unsigned int cmd, void __user *arg)
> sipx->sipx_network = ipxif->if_netnum;
> memcpy(sipx->sipx_node, ipxif->if_node,
> sizeof(sipx->sipx_node));
> - rc = -EFAULT;
> + rc = 0;
> if (copy_to_user(arg, &ifr, sizeof(ifr)))
> - break;
> + rc = -EFAULT;
> ipxitf_put(ipxif);
> - rc = 0;
> break;
> }
> case SIOCAIPXITFCRT:
This refcount overflow flaw (and resulting use-after-free) appears to
be reachable from unprivileged userspace, though I think it requires
an interface already be configured, so this is likely not much risk to
most users. Someone more familiar with IPX should double-check...
And, of course, I should point out this flaw would have been blocked
entirely by using refcount_t:
https://lkml.org/lkml/2017/3/17/193
And if it didn't require a configured interface, it would be mitigated
with module autoload blocking:
https://lkml.org/lkml/2017/4/19/1088
(Yes, yes, I know both are still being worked on, but this is a good
example to show another case where they'd have been useful.)
-Kees
--
Kees Cook
Pixel Security
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2017-05-02 23:42 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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[not found] <143C0AFC63FC204CB0C55BB88F3A8ABB33419ED1@EX02.corp.qihoo.net>
2017-05-02 10:58 ` [PATCH] ipx: call ipxitf_put() in ioctl error path Dan Carpenter
2017-05-02 19:35 ` David Miller
2017-05-02 23:42 ` Kees Cook
2017-05-02 23:42 ` [kernel-hardening] " Kees Cook
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