af_unix: Allow credentials to work across user and pid namespaces. (7361c36c) · Commits · 戴 / test

include/net/af_unix.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -23,7 +23,8 @@ struct unix_address {
		};

		struct unix_skb_parms {
		struct ucred creds; /* Skb credentials */
		struct pid pid; / Skb credentials */
		const struct cred *cred;
		struct scm_fp_list fp; / Passed files */
		#ifdef CONFIG_SECURITY_NETWORK
		u32 secid; /* Security ID */
		@@ -31,7 +32,6 @@ struct unix_skb_parms {
		};

		#define UNIXCB(skb) ((struct unix_skb_parms )&((skb)->cb))
		#define UNIXCREDS(skb) (&UNIXCB((skb)).creds)
		#define UNIXSID(skb) (&UNIXCB((skb)).secid)

		#define unix_state_lock(s) spin_lock(&unix_sk(s)->lock)

net/unix/af_unix.c

+31 −22

Original line number	Diff line number	Diff line
		@@ -1316,17 +1316,19 @@ static void unix_detach_fds(struct scm_cookie scm, struct sk_buff skb)
		int i;

		scm->fp = UNIXCB(skb).fp;
		skb->destructor = sock_wfree;
		UNIXCB(skb).fp = NULL;

		for (i = scm->fp->count-1; i >= 0; i--)
		unix_notinflight(scm->fp->fp[i]);
		}

		static void unix_destruct_fds(struct sk_buff *skb)
		static void unix_destruct_scm(struct sk_buff *skb)
		{
		struct scm_cookie scm;
		memset(&scm, 0, sizeof(scm));
		scm.pid = UNIXCB(skb).pid;
		scm.cred = UNIXCB(skb).cred;
		if (UNIXCB(skb).fp)
		unix_detach_fds(&scm, skb);

		/* Alas, it calls VFS */
		@@ -1350,10 +1352,22 @@ static int unix_attach_fds(struct scm_cookie scm, struct sk_buff skb)

		for (i = scm->fp->count-1; i >= 0; i--)
		unix_inflight(scm->fp->fp[i]);
		skb->destructor = unix_destruct_fds;
		return 0;
		}

		static int unix_scm_to_skb(struct scm_cookie scm, struct sk_buff skb, bool send_fds)
		{
		int err = 0;
		UNIXCB(skb).pid = get_pid(scm->pid);
		UNIXCB(skb).cred = get_cred(scm->cred);
		UNIXCB(skb).fp = NULL;
		if (scm->fp && send_fds)
		err = unix_attach_fds(scm, skb);

		skb->destructor = unix_destruct_scm;
		return err;
		}

		/*
		* Send AF_UNIX data.
		*/
		@@ -1410,12 +1424,9 @@ static int unix_dgram_sendmsg(struct kiocb kiocb, struct socket sock,
		if (skb == NULL)
		goto out;

		memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
		if (siocb->scm->fp) {
		err = unix_attach_fds(siocb->scm, skb);
		err = unix_scm_to_skb(siocb->scm, skb, true);
		if (err)
		goto out_free;
		}
		unix_get_secdata(siocb->scm, skb);

		skb_reset_transport_header(skb);
		@@ -1585,16 +1596,14 @@ static int unix_stream_sendmsg(struct kiocb kiocb, struct socket sock,
		*/
		size = min_t(int, size, skb_tailroom(skb));

		memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred));

		/* Only send the fds in the first buffer */
		if (siocb->scm->fp && !fds_sent) {
		err = unix_attach_fds(siocb->scm, skb);
		err = unix_scm_to_skb(siocb->scm, skb, !fds_sent);
		if (err) {
		kfree_skb(skb);
		goto out_err;
		}
		fds_sent = true;
		}

		err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
		if (err) {
		@@ -1711,7 +1720,7 @@ static int unix_dgram_recvmsg(struct kiocb iocb, struct socket sock,
		siocb->scm = &tmp_scm;
		memset(&tmp_scm, 0, sizeof(tmp_scm));
		}
		siocb->scm->creds = *UNIXCREDS(skb);
		scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
		unix_set_secdata(siocb->scm, skb);

		if (!(flags & MSG_PEEK)) {
		@@ -1860,14 +1869,14 @@ static int unix_stream_recvmsg(struct kiocb iocb, struct socket sock,

		if (check_creds) {
		/* Never glue messages from different writers */
		if (memcmp(UNIXCREDS(skb), &siocb->scm->creds,
		sizeof(siocb->scm->creds)) != 0) {
		if ((UNIXCB(skb).pid != siocb->scm->pid) \|\|
		(UNIXCB(skb).cred != siocb->scm->cred)) {
		skb_queue_head(&sk->sk_receive_queue, skb);
		break;
		}
		} else {
		/* Copy credentials */
		siocb->scm->creds = *UNIXCREDS(skb);
		scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
		check_creds = 1;
		}

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