f8d570a474
__scm_destroy() walks the list of file descriptors in the scm_fp_list pointed to by the scm_cookie argument. Those, in turn, can close sockets and invoke __scm_destroy() again. There is nothing which limits how deeply this can occur. The idea for how to fix this is from Linus. Basically, we do all of the fput()s at the top level by collecting all of the scm_fp_list objects hit by an fput(). Inside of the initial __scm_destroy() we keep running the list until it is empty. Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
114 lines
2.8 KiB
C
114 lines
2.8 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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#include <linux/pid.h>
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#include <linux/nsproxy.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 255
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struct scm_fp_list
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{
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struct list_head list;
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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 = task_tgid_vnr(p);
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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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