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authorCatherine Zhang <cxzhang@watson.ibm.com>2006-08-03 01:12:06 +0400
committerDavid S. Miller <davem@davemloft.net>2006-08-03 01:12:06 +0400
commitdc49c1f94e3469d94b952e8f5160dd4ccd791d79 (patch)
treee47b1974c262a03dbabf0a148325d9089817e78e /include/net
parent2b7e24b66d31d677d76b49918e711eb360c978b6 (diff)
downloadlinux-dc49c1f94e3469d94b952e8f5160dd4ccd791d79.tar.xz
[AF_UNIX]: Kernel memory leak fix for af_unix datagram getpeersec patch
From: Catherine Zhang <cxzhang@watson.ibm.com> This patch implements a cleaner fix for the memory leak problem of the original unix datagram getpeersec patch. Instead of creating a security context each time a unix datagram is sent, we only create the security context when the receiver requests it. This new design requires modification of the current unix_getsecpeer_dgram LSM hook and addition of two new hooks, namely, secid_to_secctx and release_secctx. The former retrieves the security context and the latter releases it. A hook is required for releasing the security context because it is up to the security module to decide how that's done. In the case of Selinux, it's a simple kfree operation. Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net')
-rw-r--r--include/net/af_unix.h6
-rw-r--r--include/net/scm.h29
2 files changed, 27 insertions, 8 deletions
diff --git a/include/net/af_unix.h b/include/net/af_unix.h
index 2fec827c8801..c0398f5a8cb9 100644
--- a/include/net/af_unix.h
+++ b/include/net/af_unix.h
@@ -54,15 +54,13 @@ struct unix_skb_parms {
struct ucred creds; /* Skb credentials */
struct scm_fp_list *fp; /* Passed files */
#ifdef CONFIG_SECURITY_NETWORK
- char *secdata; /* Security context */
- u32 seclen; /* Security length */
+ u32 secid; /* Security ID */
#endif
};
#define UNIXCB(skb) (*(struct unix_skb_parms*)&((skb)->cb))
#define UNIXCREDS(skb) (&UNIXCB((skb)).creds)
-#define UNIXSECDATA(skb) (&UNIXCB((skb)).secdata)
-#define UNIXSECLEN(skb) (&UNIXCB((skb)).seclen)
+#define UNIXSID(skb) (&UNIXCB((skb)).secid)
#define unix_state_rlock(s) spin_lock(&unix_sk(s)->lock)
#define unix_state_runlock(s) spin_unlock(&unix_sk(s)->lock)
diff --git a/include/net/scm.h b/include/net/scm.h
index 02daa097cdcd..5637d5e22d5f 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -3,6 +3,7 @@
#include <linux/limits.h>
#include <linux/net.h>
+#include <linux/security.h>
/* Well, we should have at least one descriptor open
* to accept passed FDs 8)
@@ -20,8 +21,7 @@ struct scm_cookie
struct ucred creds; /* Skb credentials */
struct scm_fp_list *fp; /* Passed files */
#ifdef CONFIG_SECURITY_NETWORK
- char *secdata; /* Security context */
- u32 seclen; /* Security length */
+ u32 secid; /* Passed security ID */
#endif
unsigned long seq; /* Connection seqno */
};
@@ -32,6 +32,16 @@ extern int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie
extern void __scm_destroy(struct scm_cookie *scm);
extern struct scm_fp_list * scm_fp_dup(struct scm_fp_list *fpl);
+#ifdef CONFIG_SECURITY_NETWORK
+static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
+{
+ security_socket_getpeersec_dgram(sock, NULL, &scm->secid);
+}
+#else
+static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
+{ }
+#endif /* CONFIG_SECURITY_NETWORK */
+
static __inline__ void scm_destroy(struct scm_cookie *scm)
{
if (scm && scm->fp)
@@ -47,6 +57,7 @@ static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
scm->creds.pid = p->tgid;
scm->fp = NULL;
scm->seq = 0;
+ unix_get_peersec_dgram(sock, scm);
if (msg->msg_controllen <= 0)
return 0;
return __scm_send(sock, msg, scm);
@@ -55,8 +66,18 @@ static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
#ifdef CONFIG_SECURITY_NETWORK
static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
{
- if (test_bit(SOCK_PASSSEC, &sock->flags) && scm->secdata != NULL)
- put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, scm->seclen, scm->secdata);
+ char *secdata;
+ u32 seclen;
+ int err;
+
+ if (test_bit(SOCK_PASSSEC, &sock->flags)) {
+ err = security_secid_to_secctx(scm->secid, &secdata, &seclen);
+
+ if (!err) {
+ put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
+ security_release_secctx(secdata, seclen);
+ }
+ }
}
#else
static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)