netdev - [PATCH] net: Fix ns_capable check in sock_diag_put

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Date:	Wed, 16 Apr 2014 21:41:34 -0700
From:	Andy Lutomirski <luto@...capital.net>
To:	"Eric W. Biederman" <ebiederm@...ssion.com>, netdev@...r.kernel.org
Cc:	Andy Lutomirski <luto@...capital.net>, stable@...r.kernel.org
Subject: [PATCH] net: Fix ns_capable check in sock_diag_put_filterinfo

The caller needs capabilities on the namespace being queried, not on
their own namespace.  This is a security bug, although it likely has
only a minor impact.

Cc: stable@...r.kernel.org
Signed-off-by: Andy Lutomirski <luto@...capital.net>
---

Someone should check that I'm right.  I had trouble getting 'ss -b' to
work, even with plain old sudo.

 include/linux/sock_diag.h | 2 +-
 net/core/sock_diag.c      | 4 ++--
 net/packet/diag.c         | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/linux/sock_diag.h b/include/linux/sock_diag.h
index 54f91d3..302ab80 100644
--- a/include/linux/sock_diag.h
+++ b/include/linux/sock_diag.h
@@ -23,7 +23,7 @@ int sock_diag_check_cookie(void *sk, __u32 *cookie);
 void sock_diag_save_cookie(void *sk, __u32 *cookie);
 
 int sock_diag_put_meminfo(struct sock *sk, struct sk_buff *skb, int attr);
-int sock_diag_put_filterinfo(struct user_namespace *user_ns, struct sock *sk,
+int sock_diag_put_filterinfo(struct sock *sk,
 			     struct sk_buff *skb, int attrtype);
 
 #endif
diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c
index a0e9cf6..6a7fae2 100644
--- a/net/core/sock_diag.c
+++ b/net/core/sock_diag.c
@@ -49,7 +49,7 @@ int sock_diag_put_meminfo(struct sock *sk, struct sk_buff *skb, int attrtype)
 }
 EXPORT_SYMBOL_GPL(sock_diag_put_meminfo);
 
-int sock_diag_put_filterinfo(struct user_namespace *user_ns, struct sock *sk,
+int sock_diag_put_filterinfo(struct sock *sk,
 			     struct sk_buff *skb, int attrtype)
 {
 	struct nlattr *attr;
@@ -57,7 +57,7 @@ int sock_diag_put_filterinfo(struct user_namespace *user_ns, struct sock *sk,
 	unsigned int len;
 	int err = 0;
 
-	if (!ns_capable(user_ns, CAP_NET_ADMIN)) {
+	if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) {
 		nla_reserve(skb, attrtype, 0);
 		return 0;
 	}
diff --git a/net/packet/diag.c b/net/packet/diag.c
index 533ce4f..435ff99 100644
--- a/net/packet/diag.c
+++ b/net/packet/diag.c
@@ -172,7 +172,7 @@ static int sk_diag_fill(struct sock *sk, struct sk_buff *skb,
 		goto out_nlmsg_trim;
 
 	if ((req->pdiag_show & PACKET_SHOW_FILTER) &&
-	    sock_diag_put_filterinfo(user_ns, sk, skb, PACKET_DIAG_FILTER))
+	    sock_diag_put_filterinfo(sk, skb, PACKET_DIAG_FILTER))
 		goto out_nlmsg_trim;
 
 	return nlmsg_end(skb, nlh);
-- 
1.9.0

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