On Fri, 12 Dec 2003, Chris Wright wrote:
> * James Morris (jmorris@private) wrote:
> > Below is a patch against 2.6.0-test11 which implements a new socket option
> > SO_PEERSEC (defined for i386 only at this stage).
>
> Thanks for doing this James. In your example demonstration, you simply
> print the peersec string. Do you expect to use with simple comparison
> against something like data from procattr, or something else? IOW,
> does this introduce any new namespace issues for apps?
Semantics are application dependent, but with SELinux, the returned
security context would be passed to a userspace SELinux API function.
I'm not sure how this would be a namespace issue -- do you mean a data
format issue?
>
> > +static inline int security_sk_alloc_security(struct sock *sk, int family, int priority)
> > +static inline void security_sk_free_security(struct sock *sk)
>
> minor nit. these names are inconsistent with the existing analogous ones.
> how about simply, security_sk_alloc and security_sk_free?
Done.
>
> > +++ linux-2.6.0-test11.w2/net/core/sock.c 2003-12-10 09:55:39.378901360 -0500
> > @@ -564,6 +564,9 @@
> > v.val = sk->sk_state == TCP_LISTEN;
> > break;
> >
> > + case SO_PEERSEC:
> > + return security_socket_getpeersec(sock, optval, len);
> > +
>
> Would it be useful to ask the module to update len as is done in some
> other cases.
Yep, allowing the security module to update the returned length is now
implemented.
> Perhaps buffer is too small, can len be vector for that info?
I would not advise updating len on error -- it's a bad idea in general to
interpret any returned data from failed syscalls except the error number.
An updated patch is below, which implements the above, as well as previous
feedback from David. This one includes the changes to SELinux so it's
easier to see example usage.
- James
--
James Morris
<jmorris@private>
diff -urN -X dontdiff linux-2.6.0-test11.orig/include/asm-i386/socket.h linux-2.6.0-test11.w1/include/asm-i386/socket.h
--- linux-2.6.0-test11.orig/include/asm-i386/socket.h 2003-09-27 20:50:09.000000000 -0400
+++ linux-2.6.0-test11.w1/include/asm-i386/socket.h 2003-12-12 20:24:34.000000000 -0500
@@ -45,6 +45,8 @@
#define SO_ACCEPTCONN 30
+#define SO_PEERSEC 31
+
/* Nasty libc5 fixup - bletch */
#if defined(__KERNEL__) || !defined(__GLIBC__) || (__GLIBC__ < 2)
/* Socket types. */
diff -urN -X dontdiff linux-2.6.0-test11.orig/include/linux/security.h linux-2.6.0-test11.w1/include/linux/security.h
--- linux-2.6.0-test11.orig/include/linux/security.h 2003-10-15 08:53:19.000000000 -0400
+++ linux-2.6.0-test11.w1/include/linux/security.h 2003-12-12 21:43:53.000000000 -0500
@@ -757,6 +757,21 @@
* incoming sk_buff @skb has been associated with a particular socket, @sk.
* @sk contains the sock (not socket) associated with the incoming sk_buff.
* @skb contains the incoming network data.
+ * @socket_getpeersec:
+ * This hook allows the security module to provide peer socket security
+ * state to userspace via getsockopt SO_GETPEERSEC.
+ * @sock is the local socket.
+ * @optval userspace memory where the security state is to be copied.
+ * @len as input is the maximum length to copy to userspace provided
+ * by the caller. The module should change this to the actual
+ * length copied.
+ * Return 0 if all is well, otherwise, typical getsockopt return
+ * values.
+ * @sk_alloc_security:
+ * Allocate and attach a security structure to the sk->sk_security field,
+ * which is used to copy security attributes between local stream sockets.
+ * @sk_free_security:
+ * Deallocate security structure.
*
* Security hooks affecting all System V IPC operations.
*
@@ -1183,6 +1198,9 @@
int (*socket_setsockopt) (struct socket * sock, int level, int optname);
int (*socket_shutdown) (struct socket * sock, int how);
int (*socket_sock_rcv_skb) (struct sock * sk, struct sk_buff * skb);
+ int (*socket_getpeersec) (struct socket *sock, char __user *optval, unsigned *len);
+ int (*sk_alloc_security) (struct sock *sk, int family, int priority);
+ void (*sk_free_security) (struct sock *sk);
#endif /* CONFIG_SECURITY_NETWORK */
};
@@ -2564,6 +2582,22 @@
{
return security_ops->socket_sock_rcv_skb (sk, skb);
}
+
+static inline int security_socket_getpeersec(struct socket *sock,
+ char __user *optval, unsigned *len)
+{
+ return security_ops->socket_getpeersec(sock, optval, len);
+}
+
+static inline int security_sk_alloc(struct sock *sk, int family, int priority)
+{
+ return security_ops->sk_alloc_security(sk, family, priority);
+}
+
+static inline void security_sk_free(struct sock *sk)
+{
+ return security_ops->sk_free_security(sk);
+}
#else /* CONFIG_SECURITY_NETWORK */
static inline int security_unix_stream_connect(struct socket * sock,
struct socket * other,
@@ -2664,6 +2698,21 @@
{
return 0;
}
+
+static inline int security_socket_getpeersec(struct socket *sock,
+ char __user *optval, unsigned *len)
+{
+ return -ENOPROTOOPT;
+}
+
+static inline int security_sk_alloc(struct sock *sk, int family, int priority)
+{
+ return 0;
+}
+
+static inline void security_sk_free(struct sock *sk)
+{
+}
#endif /* CONFIG_SECURITY_NETWORK */
#endif /* ! __LINUX_SECURITY_H */
diff -urN -X dontdiff linux-2.6.0-test11.orig/include/net/sock.h linux-2.6.0-test11.w1/include/net/sock.h
--- linux-2.6.0-test11.orig/include/net/sock.h 2003-12-01 15:27:07.000000000 -0500
+++ linux-2.6.0-test11.w1/include/net/sock.h 2003-12-12 20:44:15.000000000 -0500
@@ -246,6 +246,7 @@
struct socket *sk_socket;
void *sk_user_data;
struct module *sk_owner;
+ void *sk_security;
void (*sk_state_change)(struct sock *sk);
void (*sk_data_ready)(struct sock *sk, int bytes);
void (*sk_write_space)(struct sock *sk);
diff -urN -X dontdiff linux-2.6.0-test11.orig/net/core/sock.c linux-2.6.0-test11.w1/net/core/sock.c
--- linux-2.6.0-test11.orig/net/core/sock.c 2003-12-01 15:27:04.000000000 -0500
+++ linux-2.6.0-test11.w1/net/core/sock.c 2003-12-12 21:43:54.000000000 -0500
@@ -564,6 +564,13 @@
v.val = sk->sk_state == TCP_LISTEN;
break;
+ case SO_PEERSEC: {
+ int err = security_socket_getpeersec(sock, optval, &len);
+ if (err)
+ return err;
+ goto lenout;
+ }
+
default:
return(-ENOPROTOOPT);
}
@@ -606,6 +613,11 @@
sock_lock_init(sk);
}
sk->sk_slab = slab;
+
+ if (security_sk_alloc(sk, family, priority)) {
+ kmem_cache_free(sk->sk_slab, sk);
+ sk = NULL;
+ }
}
return sk;
}
@@ -628,6 +640,7 @@
printk(KERN_DEBUG "%s: optmem leakage (%d bytes) detected.\n",
__FUNCTION__, atomic_read(&sk->sk_omem_alloc));
+ security_sk_free(sk);
kmem_cache_free(sk->sk_slab, sk);
module_put(owner);
}
diff -urN -X dontdiff linux-2.6.0-test11.orig/security/dummy.c linux-2.6.0-test11.w1/security/dummy.c
--- linux-2.6.0-test11.orig/security/dummy.c 2003-10-15 08:53:19.000000000 -0400
+++ linux-2.6.0-test11.w1/security/dummy.c 2003-12-12 21:45:08.000000000 -0500
@@ -793,6 +793,21 @@
{
return 0;
}
+
+static int dummy_socket_getpeersec(struct socket *sock,
+ char __user *optval, unsigned *len)
+{
+ return -ENOPROTOOPT;
+}
+
+static inline int dummy_sk_alloc_security (struct sock *sk, int family, int priority)
+{
+ return 0;
+}
+
+static inline void dummy_sk_free_security (struct sock *sk)
+{
+}
#endif /* CONFIG_SECURITY_NETWORK */
static int dummy_register_security (const char *name, struct security_operations *ops)
@@ -969,6 +984,9 @@
set_to_dummy_if_null(ops, socket_getsockopt);
set_to_dummy_if_null(ops, socket_shutdown);
set_to_dummy_if_null(ops, socket_sock_rcv_skb);
+ set_to_dummy_if_null(ops, socket_getpeersec);
+ set_to_dummy_if_null(ops, sk_alloc_security);
+ set_to_dummy_if_null(ops, sk_free_security);
#endif /* CONFIG_SECURITY_NETWORK */
}
diff -urN -X dontdiff linux-2.6.0-test11.orig/security/selinux/hooks.c linux-2.6.0-test11.w1/security/selinux/hooks.c
--- linux-2.6.0-test11.orig/security/selinux/hooks.c 2003-10-15 08:53:19.000000000 -0400
+++ linux-2.6.0-test11.w1/security/selinux/hooks.c 2003-12-12 22:06:21.000000000 -0500
@@ -242,6 +242,39 @@
kfree(sbsec);
}
+#ifdef CONFIG_SECURITY_NETWORK
+static int sk_alloc_security(struct sock *sk, int family, int priority)
+{
+ struct sk_security_struct *ssec;
+
+ if (family != PF_UNIX)
+ return 0;
+
+ ssec = kmalloc(sizeof(*ssec), priority);
+ if (!ssec)
+ return -ENOMEM;
+
+ memset(ssec, 0, sizeof(*ssec));
+ ssec->magic = SELINUX_MAGIC;
+ ssec->sk = sk;
+ ssec->peer_sid = SECINITSID_UNLABELED;
+ sk->sk_security = ssec;
+
+ return 0;
+}
+
+static void sk_free_security(struct sock *sk)
+{
+ struct task_security_struct *ssec = sk->sk_security;
+
+ if (sk->sk_family != PF_UNIX || ssec->magic != SELINUX_MAGIC)
+ return;
+
+ sk->sk_security = NULL;
+ kfree(ssec);
+}
+#endif /* CONFIG_SECURITY_NETWORK */
+
/* The security server must be initialized before
any labeling or access decisions can be provided. */
extern int ss_initialized;
@@ -2576,6 +2609,7 @@
struct socket *other,
struct sock *newsk)
{
+ struct sk_security_struct *ssec;
struct inode_security_struct *isec;
struct inode_security_struct *other_isec;
struct avc_audit_data ad;
@@ -2594,6 +2628,14 @@
if (err)
return err;
+ /* connecting socket */
+ ssec = sock->sk->sk_security;
+ ssec->peer_sid = other_isec->sid;
+
+ /* server child socket */
+ ssec = newsk->sk_security;
+ ssec->peer_sid = isec->sid;
+
return 0;
}
@@ -2621,6 +2663,53 @@
return 0;
}
+static int selinux_socket_getpeersec(struct socket *sock,
+ char __user *optval, unsigned *len)
+{
+ int err = 0;
+ char *scontext;
+ u32 scontext_len;
+ struct sk_security_struct *ssec;
+ struct inode_security_struct *isec;
+
+ isec = SOCK_INODE(sock)->i_security;
+ if (isec->sclass != SECCLASS_UNIX_STREAM_SOCKET) {
+ err = -ENOPROTOOPT;
+ goto out;
+ }
+
+ ssec = sock->sk->sk_security;
+
+ err = security_sid_to_context(ssec->peer_sid, &scontext, &scontext_len);
+ if (err)
+ goto out;
+
+ if (scontext_len > *len) {
+ err = -ENOSPC;
+ goto out_free;
+ }
+
+ if (copy_to_user(optval, scontext, scontext_len))
+ err = -EFAULT;
+
+ *len = scontext_len;
+
+out_free:
+ kfree(scontext);
+out:
+ return err;
+}
+
+static int selinux_sk_alloc_security(struct sock *sk, int family, int priority)
+{
+ return sk_alloc_security(sk, family, priority);
+}
+
+static void selinux_sk_free_security(struct sock *sk)
+{
+ sk_free_security(sk);
+}
+
#endif
static int ipc_alloc_security(struct task_struct *task,
@@ -3356,6 +3445,9 @@
.socket_getsockopt = selinux_socket_getsockopt,
.socket_setsockopt = selinux_socket_setsockopt,
.socket_shutdown = selinux_socket_shutdown,
+ .socket_getpeersec = selinux_socket_getpeersec,
+ .sk_alloc_security = selinux_sk_alloc_security,
+ .sk_free_security = selinux_sk_free_security,
#endif
};
diff -urN -X dontdiff linux-2.6.0-test11.orig/security/selinux/include/objsec.h linux-2.6.0-test11.w1/security/selinux/include/objsec.h
--- linux-2.6.0-test11.orig/security/selinux/include/objsec.h 2003-09-27 20:50:18.000000000 -0400
+++ linux-2.6.0-test11.w1/security/selinux/include/objsec.h 2003-12-12 20:24:39.000000000 -0500
@@ -93,6 +93,12 @@
unsigned char set;
};
+struct sk_security_struct {
+ unsigned long magic; /* magic number for this module */
+ struct sock *sk; /* back pointer to sk object */
+ u32 peer_sid; /* SID of peer */
+};
+
extern int inode_security_set_sid(struct inode *inode, u32 sid);
#endif /* _SELINUX_OBJSEC_H_ */
This archive was generated by hypermail 2b30 : Fri Dec 12 2003 - 19:45:32 PST