[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>
This commit is contained in:
Catherine Zhang
David S. Miller
Родитель
2b7e24b66d
Коммит
dc49c1f94e
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@ -1109,6 +1109,16 @@ struct swap_info_struct;
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* @name contains the name of the security module being unstacked.
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* @ops contains a pointer to the struct security_operations of the module to unstack.
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*
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* @secid_to_secctx:
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* Convert secid to security context.
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* @secid contains the security ID.
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* @secdata contains the pointer that stores the converted security context.
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*
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* @release_secctx:
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* Release the security context.
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* @secdata contains the security context.
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* @seclen contains the length of the security context.
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*
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* This is the main security structure.
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*/
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struct security_operations {
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@ -1289,6 +1299,8 @@ struct security_operations {
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int (*getprocattr)(struct task_struct *p, char *name, void *value, size_t size);
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int (*setprocattr)(struct task_struct *p, char *name, void *value, size_t size);
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int (*secid_to_secctx)(u32 secid, char **secdata, u32 *seclen);
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void (*release_secctx)(char *secdata, u32 seclen);
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#ifdef CONFIG_SECURITY_NETWORK
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int (*unix_stream_connect) (struct socket * sock,
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@ -1317,7 +1329,7 @@ struct security_operations {
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int (*socket_shutdown) (struct socket * sock, int how);
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int (*socket_sock_rcv_skb) (struct sock * sk, struct sk_buff * skb);
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int (*socket_getpeersec_stream) (struct socket *sock, char __user *optval, int __user *optlen, unsigned len);
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int (*socket_getpeersec_dgram) (struct sk_buff *skb, char **secdata, u32 *seclen);
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int (*socket_getpeersec_dgram) (struct socket *sock, struct sk_buff *skb, u32 *secid);
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int (*sk_alloc_security) (struct sock *sk, int family, gfp_t priority);
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void (*sk_free_security) (struct sock *sk);
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unsigned int (*sk_getsid) (struct sock *sk, struct flowi *fl, u8 dir);
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@ -2059,6 +2071,16 @@ static inline int security_netlink_recv(struct sk_buff * skb, int cap)
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return security_ops->netlink_recv(skb, cap);
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}
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static inline int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
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{
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return security_ops->secid_to_secctx(secid, secdata, seclen);
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}
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static inline void security_release_secctx(char *secdata, u32 seclen)
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{
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return security_ops->release_secctx(secdata, seclen);
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}
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/* prototypes */
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extern int security_init (void);
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extern int register_security (struct security_operations *ops);
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@ -2725,6 +2747,15 @@ static inline void securityfs_remove(struct dentry *dentry)
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{
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}
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static inline int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
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{
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return -EOPNOTSUPP;
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}
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static inline void security_release_secctx(char *secdata, u32 seclen)
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{
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return -EOPNOTSUPP;
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}
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#endif /* CONFIG_SECURITY */
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#ifdef CONFIG_SECURITY_NETWORK
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@ -2840,10 +2871,9 @@ static inline int security_socket_getpeersec_stream(struct socket *sock, char __
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return security_ops->socket_getpeersec_stream(sock, optval, optlen, len);
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}
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static inline int security_socket_getpeersec_dgram(struct sk_buff *skb, char **secdata,
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u32 *seclen)
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static inline int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid)
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{
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return security_ops->socket_getpeersec_dgram(skb, secdata, seclen);
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return security_ops->socket_getpeersec_dgram(sock, skb, secid);
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}
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static inline int security_sk_alloc(struct sock *sk, int family, gfp_t priority)
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@ -2968,8 +2998,7 @@ static inline int security_socket_getpeersec_stream(struct socket *sock, char __
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return -ENOPROTOOPT;
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}
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static inline int security_socket_getpeersec_dgram(struct sk_buff *skb, char **secdata,
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u32 *seclen)
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static inline int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid)
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{
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return -ENOPROTOOPT;
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}
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@ -54,15 +54,13 @@ struct unix_skb_parms {
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struct ucred creds; /* Skb credentials */
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struct scm_fp_list *fp; /* Passed files */
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#ifdef CONFIG_SECURITY_NETWORK
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char *secdata; /* Security context */
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u32 seclen; /* Security length */
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u32 secid; /* Security ID */
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#endif
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};
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#define UNIXCB(skb) (*(struct unix_skb_parms*)&((skb)->cb))
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#define UNIXCREDS(skb) (&UNIXCB((skb)).creds)
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#define UNIXSECDATA(skb) (&UNIXCB((skb)).secdata)
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#define UNIXSECLEN(skb) (&UNIXCB((skb)).seclen)
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#define UNIXSID(skb) (&UNIXCB((skb)).secid)
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#define unix_state_rlock(s) spin_lock(&unix_sk(s)->lock)
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#define unix_state_runlock(s) spin_unlock(&unix_sk(s)->lock)
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@ -3,6 +3,7 @@
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#include <linux/limits.h>
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#include <linux/net.h>
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#include <linux/security.h>
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/* Well, we should have at least one descriptor open
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* to accept passed FDs 8)
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@ -20,8 +21,7 @@ struct scm_cookie
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struct ucred creds; /* Skb credentials */
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struct scm_fp_list *fp; /* Passed files */
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#ifdef CONFIG_SECURITY_NETWORK
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char *secdata; /* Security context */
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u32 seclen; /* Security length */
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u32 secid; /* Passed security ID */
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#endif
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unsigned long seq; /* Connection seqno */
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};
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@ -32,6 +32,16 @@ extern int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie
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extern void __scm_destroy(struct scm_cookie *scm);
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extern struct scm_fp_list * scm_fp_dup(struct scm_fp_list *fpl);
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#ifdef CONFIG_SECURITY_NETWORK
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static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
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{
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security_socket_getpeersec_dgram(sock, NULL, &scm->secid);
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}
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#else
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static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
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{ }
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#endif /* CONFIG_SECURITY_NETWORK */
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static __inline__ void scm_destroy(struct scm_cookie *scm)
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{
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if (scm && scm->fp)
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@ -47,6 +57,7 @@ static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
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scm->creds.pid = p->tgid;
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scm->fp = NULL;
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scm->seq = 0;
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unix_get_peersec_dgram(sock, scm);
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if (msg->msg_controllen <= 0)
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return 0;
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return __scm_send(sock, msg, scm);
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@ -55,8 +66,18 @@ static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
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#ifdef CONFIG_SECURITY_NETWORK
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static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
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{
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if (test_bit(SOCK_PASSSEC, &sock->flags) && scm->secdata != NULL)
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put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, scm->seclen, scm->secdata);
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char *secdata;
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u32 seclen;
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int err;
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if (test_bit(SOCK_PASSSEC, &sock->flags)) {
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err = security_secid_to_secctx(scm->secid, &secdata, &seclen);
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if (!err) {
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put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
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security_release_secctx(secdata, seclen);
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}
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}
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}
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#else
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static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
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@ -112,14 +112,19 @@ static void ip_cmsg_recv_retopts(struct msghdr *msg, struct sk_buff *skb)
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static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
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{
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char *secdata;
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u32 seclen;
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u32 seclen, secid;
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int err;
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err = security_socket_getpeersec_dgram(skb, &secdata, &seclen);
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err = security_socket_getpeersec_dgram(NULL, skb, &secid);
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if (err)
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return;
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err = security_secid_to_secctx(secid, &secdata, &seclen);
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if (err)
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return;
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put_cmsg(msg, SOL_IP, SCM_SECURITY, seclen, secdata);
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security_release_secctx(secdata, seclen);
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}
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@ -128,23 +128,17 @@ static atomic_t unix_nr_socks = ATOMIC_INIT(0);
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#define UNIX_ABSTRACT(sk) (unix_sk(sk)->addr->hash != UNIX_HASH_SIZE)
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#ifdef CONFIG_SECURITY_NETWORK
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static void unix_get_peersec_dgram(struct sk_buff *skb)
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static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
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{
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int err;
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err = security_socket_getpeersec_dgram(skb, UNIXSECDATA(skb),
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UNIXSECLEN(skb));
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if (err)
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*(UNIXSECDATA(skb)) = NULL;
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memcpy(UNIXSID(skb), &scm->secid, sizeof(u32));
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}
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static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
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{
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scm->secdata = *UNIXSECDATA(skb);
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scm->seclen = *UNIXSECLEN(skb);
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scm->secid = *UNIXSID(skb);
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}
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#else
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static inline void unix_get_peersec_dgram(struct sk_buff *skb)
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static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
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{ }
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static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
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@ -1322,8 +1316,7 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
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memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
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if (siocb->scm->fp)
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unix_attach_fds(siocb->scm, skb);
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unix_get_peersec_dgram(skb);
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unix_get_secdata(siocb->scm, skb);
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skb->h.raw = skb->data;
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err = memcpy_fromiovec(skb_put(skb,len), msg->msg_iov, len);
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@ -791,8 +791,7 @@ static int dummy_socket_getpeersec_stream(struct socket *sock, char __user *optv
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return -ENOPROTOOPT;
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}
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static int dummy_socket_getpeersec_dgram(struct sk_buff *skb, char **secdata,
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u32 *seclen)
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static int dummy_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid)
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{
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return -ENOPROTOOPT;
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}
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@ -876,6 +875,15 @@ static int dummy_setprocattr(struct task_struct *p, char *name, void *value, siz
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return -EINVAL;
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}
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static int dummy_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
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{
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return -EOPNOTSUPP;
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}
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static void dummy_release_secctx(char *secdata, u32 seclen)
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{
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}
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#ifdef CONFIG_KEYS
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static inline int dummy_key_alloc(struct key *key, struct task_struct *ctx,
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unsigned long flags)
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@ -1028,6 +1036,8 @@ void security_fixup_ops (struct security_operations *ops)
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set_to_dummy_if_null(ops, d_instantiate);
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set_to_dummy_if_null(ops, getprocattr);
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set_to_dummy_if_null(ops, setprocattr);
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set_to_dummy_if_null(ops, secid_to_secctx);
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set_to_dummy_if_null(ops, release_secctx);
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#ifdef CONFIG_SECURITY_NETWORK
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set_to_dummy_if_null(ops, unix_stream_connect);
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set_to_dummy_if_null(ops, unix_may_send);
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@ -3524,25 +3524,21 @@ out:
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return err;
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}
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static int selinux_socket_getpeersec_dgram(struct sk_buff *skb, char **secdata, u32 *seclen)
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static int selinux_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid)
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{
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u32 peer_secid = SECSID_NULL;
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int err = 0;
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u32 peer_sid;
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if (skb->sk->sk_family == PF_UNIX)
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selinux_get_inode_sid(SOCK_INODE(skb->sk->sk_socket),
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&peer_sid);
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else
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peer_sid = selinux_socket_getpeer_dgram(skb);
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if (sock && (sock->sk->sk_family == PF_UNIX))
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selinux_get_inode_sid(SOCK_INODE(sock), &peer_secid);
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else if (skb)
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peer_secid = selinux_socket_getpeer_dgram(skb);
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if (peer_sid == SECSID_NULL)
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return -EINVAL;
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if (peer_secid == SECSID_NULL)
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err = -EINVAL;
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*secid = peer_secid;
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err = security_sid_to_context(peer_sid, secdata, seclen);
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if (err)
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return err;
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return 0;
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return err;
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}
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static int selinux_sk_alloc_security(struct sock *sk, int family, gfp_t priority)
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@ -4407,6 +4403,17 @@ static int selinux_setprocattr(struct task_struct *p,
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return size;
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}
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static int selinux_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
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{
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return security_sid_to_context(secid, secdata, seclen);
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}
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static void selinux_release_secctx(char *secdata, u32 seclen)
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{
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if (secdata)
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kfree(secdata);
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}
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#ifdef CONFIG_KEYS
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static int selinux_key_alloc(struct key *k, struct task_struct *tsk,
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@ -4587,6 +4594,9 @@ static struct security_operations selinux_ops = {
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.getprocattr = selinux_getprocattr,
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.setprocattr = selinux_setprocattr,
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.secid_to_secctx = selinux_secid_to_secctx,
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.release_secctx = selinux_release_secctx,
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.unix_stream_connect = selinux_socket_unix_stream_connect,
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.unix_may_send = selinux_socket_unix_may_send,
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