dc49c1f94e
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>
111 lines
2.7 KiB
C
111 lines
2.7 KiB
C
#ifndef __LINUX_NET_SCM_H
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#define __LINUX_NET_SCM_H
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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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*/
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#define SCM_MAX_FD (OPEN_MAX-1)
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struct scm_fp_list
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{
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int count;
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struct file *fp[SCM_MAX_FD];
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};
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struct scm_cookie
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{
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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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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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extern void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm);
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extern void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm);
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extern int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm);
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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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__scm_destroy(scm);
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}
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static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
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struct scm_cookie *scm)
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{
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struct task_struct *p = current;
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scm->creds.uid = p->uid;
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scm->creds.gid = p->gid;
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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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}
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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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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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{ }
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#endif /* CONFIG_SECURITY_NETWORK */
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static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
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struct scm_cookie *scm, int flags)
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{
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if (!msg->msg_control)
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{
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if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
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msg->msg_flags |= MSG_CTRUNC;
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scm_destroy(scm);
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return;
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}
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if (test_bit(SOCK_PASSCRED, &sock->flags))
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put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(scm->creds), &scm->creds);
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scm_passec(sock, msg, scm);
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if (!scm->fp)
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return;
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scm_detach_fds(msg, scm);
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}
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#endif /* __LINUX_NET_SCM_H */
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