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Message-ID: <20090312162310.29454.93970.stgit@flek.lan>
Date: Thu, 12 Mar 2009 12:23:10 -0400
From: Paul Moore <paul.moore@...com>
To: linux-security-module@...r.kernel.org, selinux@...ho.nsa.gov,
netdev@...r.kernel.org
Subject: [RFC PATCH v1 3/3] netlabel: Label incoming TCP connections correctly
in Smack
This patch labels incoming TCP connections correctly in a manner very similar
to SELinux using the security_inet_conn_request() to label the request_sock.
---
include/net/netlabel.h | 5 ++++
net/netlabel/netlabel_kapi.c | 13 +++++++++++
security/smack/smack_lsm.c | 51 ++++++++++++++++++++++++++++++++----------
3 files changed, 57 insertions(+), 12 deletions(-)
diff --git a/include/net/netlabel.h b/include/net/netlabel.h
index bdb10e5..60ebbc1 100644
--- a/include/net/netlabel.h
+++ b/include/net/netlabel.h
@@ -417,6 +417,7 @@ int netlbl_conn_setattr(struct sock *sk,
const struct netlbl_lsm_secattr *secattr);
int netlbl_req_setattr(struct request_sock *req,
const struct netlbl_lsm_secattr *secattr);
+void netlbl_req_delattr(struct request_sock *req);
int netlbl_skbuff_setattr(struct sk_buff *skb,
u16 family,
const struct netlbl_lsm_secattr *secattr);
@@ -547,6 +548,10 @@ static inline int netlbl_req_setattr(struct request_sock *req,
{
return -ENOSYS;
}
+static inline void netlbl_req_delattr(struct request_sock *req)
+{
+ return;
+}
static inline int netlbl_skbuff_setattr(struct sk_buff *skb,
u16 family,
const struct netlbl_lsm_secattr *secattr)
diff --git a/net/netlabel/netlabel_kapi.c b/net/netlabel/netlabel_kapi.c
index d2e6b5a..ff43eda 100644
--- a/net/netlabel/netlabel_kapi.c
+++ b/net/netlabel/netlabel_kapi.c
@@ -844,6 +844,19 @@ req_setattr_return:
}
/**
+* netlbl_req_delattr - Delete all the NetLabel labels on a socket
+* @req: the socket
+*
+* Description:
+* Remove all the NetLabel labeling from @req.
+*
+*/
+void netlbl_req_delattr(struct request_sock *req)
+{
+ cipso_v4_req_delattr(req);
+}
+
+/**
* netlbl_skbuff_setattr - Label a packet using the correct protocol
* @skb: the packet
* @family: protocol family
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 25e953f..b648ac2 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -20,6 +20,7 @@
#include <linux/ext2_fs.h>
#include <linux/kd.h>
#include <asm/ioctls.h>
+#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/mutex.h>
@@ -2502,7 +2503,7 @@ static int smack_socket_getpeersec_dgram(struct socket *sock,
static void smack_sock_graft(struct sock *sk, struct socket *parent)
{
struct socket_smack *ssp;
- int rc;
+ struct netlbl_lsm_secattr secattr;
if (sk == NULL)
return;
@@ -2514,10 +2515,12 @@ static void smack_sock_graft(struct sock *sk, struct socket *parent)
ssp->smk_in = ssp->smk_out = current_security();
ssp->smk_packet[0] = '\0';
- rc = smack_netlabel(sk, SMACK_CIPSO_SOCKET);
- if (rc != 0)
- printk(KERN_WARNING "Smack: \"%s\" netlbl error %d.\n",
- __func__, -rc);
+ netlbl_secattr_init(&secattr);
+ if (netlbl_sock_getattr(sk, &secattr) == 0)
+ ssp->smk_labeled = SMACK_CIPSO_SOCKET;
+ else
+ ssp->smk_labeled = SMACK_UNLABELED_SOCKET;
+ netlbl_secattr_destroy(&secattr);
}
/**
@@ -2532,21 +2535,26 @@ static void smack_sock_graft(struct sock *sk, struct socket *parent)
static int smack_inet_conn_request(struct sock *sk, struct sk_buff *skb,
struct request_sock *req)
{
- struct netlbl_lsm_secattr skb_secattr;
+ u16 family = sk->sk_family;
+ struct netlbl_lsm_secattr secattr;
struct socket_smack *ssp = sk->sk_security;
+ struct sockaddr_in addr;
+ struct iphdr *hdr;
char smack[SMK_LABELLEN];
int rc;
- if (skb == NULL)
- return -EACCES;
+ /* handle mapped IPv4 packets arriving via IPv6 sockets */
+ if (family == PF_INET6 && skb->protocol == htons(ETH_P_IP))
+ family = PF_INET;
- netlbl_secattr_init(&skb_secattr);
- rc = netlbl_skbuff_getattr(skb, sk->sk_family, &skb_secattr);
+ netlbl_secattr_init(&secattr);
+ rc = netlbl_skbuff_getattr(skb, family, &secattr);
if (rc == 0)
- smack_from_secattr(&skb_secattr, smack);
+ smack_from_secattr(&secattr, smack);
else
strncpy(smack, smack_known_huh.smk_known, SMK_MAXLEN);
- netlbl_secattr_destroy(&skb_secattr);
+ netlbl_secattr_destroy(&secattr);
+
/*
* Receiving a packet requires that the other end
* be able to write here. Read access is not required.
@@ -2558,6 +2566,25 @@ static int smack_inet_conn_request(struct sock *sk, struct sk_buff *skb,
if (rc == 0)
strncpy(ssp->smk_packet, smack, SMK_MAXLEN);
+ /*
+ * We need to decide if we want to label the incoming connection here
+ * but we are unable to set the smk_labeled state here since we don't
+ * have a fully formed sock yet, just a request_sock ... so, label the
+ * request_sock and the stack will propogate the wire-label to the
+ * sock when it is created. Later, when the sock is added to its
+ * corresponding socket in sock_graft() we can set smk_labeled based
+ * on the presence of the wire-label on the newly created sock.
+ */
+ hdr = ip_hdr(skb);
+ addr.sin_addr.s_addr = hdr->saddr;
+ if (smack_host_label(&addr) == NULL) {
+ netlbl_secattr_init(&secattr);
+ smack_to_secattr(ssp->smk_out, &secattr);
+ rc = netlbl_req_setattr(req, &secattr);
+ netlbl_secattr_destroy(&secattr);
+ } else
+ netlbl_req_delattr(req);
+
return rc;
}
--
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