Re: linux-next: manual merge of the selinux tree with the net-next tree

Hi all,

On Mon, 5 Mar 2018 12:40:54 +1100 Stephen Rothwell [off-list ref] wrote:

Today's linux-next merge of the selinux tree got a conflict in:

  net/sctp/socket.c

between several refactoring commits from the net-next tree and commit:

  2277c7cd75e3 ("sctp: Add LSM hooks")

from the selinux tree.

I fixed it up (I think - see below) and can carry the fix as
necessary. This is now fixed as far as linux-next is concerned, but any
non trivial conflicts should be mentioned to your upstream maintainer
when your tree is submitted for merging.  You may also want to consider
cooperating with the maintainer of the conflicting tree to minimise any
particularly complex conflicts.

-- 
Cheers,
Stephen Rothwell

The resolution now looks like below (there were more changes to this
file in the net-next tree).  It will keep changing every time this file
is touched :-(

-- 
Cheers,
Stephen Rothwell

diff --cc net/sctp/socket.c
index 7d3476a4860d,73b34a6b5b09..000000000000

--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c

@@@ -1606,200 -1622,308 +1622,216 @@@ static int sctp_error(struct sock *sk, 
  static int sctp_msghdr_parse(const struct msghdr *msg,
  			     struct sctp_cmsgs *cmsgs);
  
 -static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len)
 +static int sctp_sendmsg_parse(struct sock *sk, struct sctp_cmsgs *cmsgs,
 +			      struct sctp_sndrcvinfo *srinfo,
 +			      const struct msghdr *msg, size_t msg_len)
  {
 -	struct net *net = sock_net(sk);
 -	struct sctp_sock *sp;
 -	struct sctp_endpoint *ep;
 -	struct sctp_association *new_asoc = NULL, *asoc = NULL;
 -	struct sctp_transport *transport, *chunk_tp;
 -	struct sctp_chunk *chunk;
 -	union sctp_addr to;
 -	struct sctp_af *af;
 -	struct sockaddr *msg_name = NULL;
 -	struct sctp_sndrcvinfo default_sinfo;
 -	struct sctp_sndrcvinfo *sinfo;
 -	struct sctp_initmsg *sinit;
 -	sctp_assoc_t associd = 0;
 -	struct sctp_cmsgs cmsgs = { NULL };
 -	enum sctp_scope scope;
 -	bool fill_sinfo_ttl = false, wait_connect = false;
 -	struct sctp_datamsg *datamsg;
 -	int msg_flags = msg->msg_flags;
 -	__u16 sinfo_flags = 0;
 -	long timeo;
 +	__u16 sflags;
  	int err;
  
 -	err = 0;
 -	sp = sctp_sk(sk);
 -	ep = sp->ep;
 +	if (sctp_sstate(sk, LISTENING) && sctp_style(sk, TCP))
 +		return -EPIPE;
  
 -	pr_debug("%s: sk:%p, msg:%p, msg_len:%zu ep:%p\n", __func__, sk,
 -		 msg, msg_len, ep);
 -
 -	/* We cannot send a message over a TCP-style listening socket. */
 -	if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING)) {
 -		err = -EPIPE;
 -		goto out_nounlock;
 -	}
 +	if (msg_len > sk->sk_sndbuf)
 +		return -EMSGSIZE;
  
 -	/* Parse out the SCTP CMSGs.  */
 -	err = sctp_msghdr_parse(msg, &cmsgs);
 +	memset(cmsgs, 0, sizeof(*cmsgs));
 +	err = sctp_msghdr_parse(msg, cmsgs);
  	if (err) {
  		pr_debug("%s: msghdr parse err:%x\n", __func__, err);
 -		goto out_nounlock;
 +		return err;
  	}
  
 -	/* Fetch the destination address for this packet.  This
 -	 * address only selects the association--it is not necessarily
 -	 * the address we will send to.
 -	 * For a peeled-off socket, msg_name is ignored.
 -	 */
 -	if (!sctp_style(sk, UDP_HIGH_BANDWIDTH) && msg->msg_name) {
 -		int msg_namelen = msg->msg_namelen;
 +	memset(srinfo, 0, sizeof(*srinfo));
 +	if (cmsgs->srinfo) {
 +		srinfo->sinfo_stream = cmsgs->srinfo->sinfo_stream;
 +		srinfo->sinfo_flags = cmsgs->srinfo->sinfo_flags;
 +		srinfo->sinfo_ppid = cmsgs->srinfo->sinfo_ppid;
 +		srinfo->sinfo_context = cmsgs->srinfo->sinfo_context;
 +		srinfo->sinfo_assoc_id = cmsgs->srinfo->sinfo_assoc_id;
 +		srinfo->sinfo_timetolive = cmsgs->srinfo->sinfo_timetolive;
 +	}
  
 -		err = sctp_verify_addr(sk, (union sctp_addr *)msg->msg_name,
 -				       msg_namelen);
 -		if (err)
 -			return err;
 +	if (cmsgs->sinfo) {
 +		srinfo->sinfo_stream = cmsgs->sinfo->snd_sid;
 +		srinfo->sinfo_flags = cmsgs->sinfo->snd_flags;
 +		srinfo->sinfo_ppid = cmsgs->sinfo->snd_ppid;
 +		srinfo->sinfo_context = cmsgs->sinfo->snd_context;
 +		srinfo->sinfo_assoc_id = cmsgs->sinfo->snd_assoc_id;
 +	}
  
 -		if (msg_namelen > sizeof(to))
 -			msg_namelen = sizeof(to);
 -		memcpy(&to, msg->msg_name, msg_namelen);
 -		msg_name = msg->msg_name;
 +	if (cmsgs->prinfo) {
 +		srinfo->sinfo_timetolive = cmsgs->prinfo->pr_value;
 +		SCTP_PR_SET_POLICY(srinfo->sinfo_flags,
 +				   cmsgs->prinfo->pr_policy);
  	}
  
 -	sinit = cmsgs.init;
 -	if (cmsgs.sinfo != NULL) {
 -		memset(&default_sinfo, 0, sizeof(default_sinfo));
 -		default_sinfo.sinfo_stream = cmsgs.sinfo->snd_sid;
 -		default_sinfo.sinfo_flags = cmsgs.sinfo->snd_flags;
 -		default_sinfo.sinfo_ppid = cmsgs.sinfo->snd_ppid;
 -		default_sinfo.sinfo_context = cmsgs.sinfo->snd_context;
 -		default_sinfo.sinfo_assoc_id = cmsgs.sinfo->snd_assoc_id;
 +	sflags = srinfo->sinfo_flags;
 +	if (!sflags && msg_len)
 +		return 0;
  
 -		sinfo = &default_sinfo;
 -		fill_sinfo_ttl = true;
 -	} else {
 -		sinfo = cmsgs.srinfo;
 -	}
 -	/* Did the user specify SNDINFO/SNDRCVINFO? */
 -	if (sinfo) {
 -		sinfo_flags = sinfo->sinfo_flags;
 -		associd = sinfo->sinfo_assoc_id;
 -	}
 +	if (sctp_style(sk, TCP) && (sflags & (SCTP_EOF | SCTP_ABORT)))
 +		return -EINVAL;
  
 -	pr_debug("%s: msg_len:%zu, sinfo_flags:0x%x\n", __func__,
 -		 msg_len, sinfo_flags);
 +	if (((sflags & SCTP_EOF) && msg_len > 0) ||
 +	    (!(sflags & (SCTP_EOF | SCTP_ABORT)) && msg_len == 0))
 +		return -EINVAL;
  
 -	/* SCTP_EOF or SCTP_ABORT cannot be set on a TCP-style socket. */
 -	if (sctp_style(sk, TCP) && (sinfo_flags & (SCTP_EOF | SCTP_ABORT))) {
 -		err = -EINVAL;
 -		goto out_nounlock;
 -	}
 +	if ((sflags & SCTP_ADDR_OVER) && !msg->msg_name)
 +		return -EINVAL;
  
 -	/* If SCTP_EOF is set, no data can be sent. Disallow sending zero
 -	 * length messages when SCTP_EOF|SCTP_ABORT is not set.
 -	 * If SCTP_ABORT is set, the message length could be non zero with
 -	 * the msg_iov set to the user abort reason.
 -	 */
 -	if (((sinfo_flags & SCTP_EOF) && (msg_len > 0)) ||
 -	    (!(sinfo_flags & (SCTP_EOF|SCTP_ABORT)) && (msg_len == 0))) {
 -		err = -EINVAL;
 -		goto out_nounlock;
 -	}
 +	return 0;
 +}
  
 -	/* If SCTP_ADDR_OVER is set, there must be an address
 -	 * specified in msg_name.
 -	 */
 -	if ((sinfo_flags & SCTP_ADDR_OVER) && (!msg->msg_name)) {
 -		err = -EINVAL;
 -		goto out_nounlock;
 -	}
 +static int sctp_sendmsg_new_asoc(struct sock *sk, __u16 sflags,
 +				 struct sctp_cmsgs *cmsgs,
 +				 union sctp_addr *daddr,
 +				 struct sctp_transport **tp)
 +{
 +	struct sctp_endpoint *ep = sctp_sk(sk)->ep;
 +	struct net *net = sock_net(sk);
 +	struct sctp_association *asoc;
 +	enum sctp_scope scope;
 +	struct cmsghdr *cmsg;
++	struct sctp_af *af;
 +	int err = -EINVAL;
  
 -	transport = NULL;
 +	*tp = NULL;
  
 -	pr_debug("%s: about to look up association\n", __func__);
 +	if (sflags & (SCTP_EOF | SCTP_ABORT))
 +		return -EINVAL;
  
 -	lock_sock(sk);
 +	if (sctp_style(sk, TCP) && (sctp_sstate(sk, ESTABLISHED) ||
 +				    sctp_sstate(sk, CLOSING)))
 +		return -EADDRNOTAVAIL;
  
 -	/* If a msg_name has been specified, assume this is to be used.  */
 -	if (msg_name) {
 -		/* Look for a matching association on the endpoint. */
 -		asoc = sctp_endpoint_lookup_assoc(ep, &to, &transport);
 +	if (sctp_endpoint_is_peeled_off(ep, daddr))
 +		return -EADDRNOTAVAIL;
  
 -		/* If we could not find a matching association on the
 -		 * endpoint, make sure that it is not a TCP-style
 -		 * socket that already has an association or there is
 -		 * no peeled-off association on another socket.
 -		 */
 -		if (!asoc &&
 -		    ((sctp_style(sk, TCP) &&
 -		      (sctp_sstate(sk, ESTABLISHED) ||
 -		       sctp_sstate(sk, CLOSING))) ||
 -		     sctp_endpoint_is_peeled_off(ep, &to))) {
 -			err = -EADDRNOTAVAIL;
 -			goto out_unlock;
 -		}
 +	if (!ep->base.bind_addr.port) {
 +		if (sctp_autobind(sk))
 +			return -EAGAIN;
  	} else {
 -		asoc = sctp_id2assoc(sk, associd);
 -		if (!asoc) {
 -			err = -EPIPE;
 -			goto out_unlock;
 -		}
 +		if (ep->base.bind_addr.port < inet_prot_sock(net) &&
 +		    !ns_capable(net->user_ns, CAP_NET_BIND_SERVICE))
 +			return -EACCES;
  	}
  
 -	if (asoc) {
 -		pr_debug("%s: just looked up association:%p\n", __func__, asoc);
 +	scope = sctp_scope(daddr);
  
 -		/* We cannot send a message on a TCP-style SCTP_SS_ESTABLISHED
 -		 * socket that has an association in CLOSED state. This can
 -		 * happen when an accepted socket has an association that is
 -		 * already CLOSED.
 -		 */
 -		if (sctp_state(asoc, CLOSED) && sctp_style(sk, TCP)) {
 -			err = -EPIPE;
 -			goto out_unlock;
 -		}
++	/* Label connection socket for first association 1-to-many
++	 * style for client sequence socket()->sendmsg(). This
++	 * needs to be done before sctp_assoc_add_peer() as that will
++	 * set up the initial packet that needs to account for any
++	 * security ip options (CIPSO/CALIPSO) added to the packet.
++	 */
++	af = sctp_get_af_specific(daddr->sa.sa_family);
++	if (!af)
++		return -EINVAL;
++	err = security_sctp_bind_connect(sk, SCTP_SENDMSG_CONNECT,
++					 (struct sockaddr *)daddr,
++					 af->sockaddr_len);
++	if (err < 0)
++		return err;
+ 
 -		if (sinfo_flags & SCTP_EOF) {
 -			pr_debug("%s: shutting down association:%p\n",
 -				 __func__, asoc);
 +	asoc = sctp_association_new(ep, sk, scope, GFP_KERNEL);
 +	if (!asoc)
 +		return -ENOMEM;
  
 -			sctp_primitive_SHUTDOWN(net, asoc, NULL);
 -			err = 0;
 -			goto out_unlock;
 -		}
 -		if (sinfo_flags & SCTP_ABORT) {
 +	if (sctp_assoc_set_bind_addr_from_ep(asoc, scope, GFP_KERNEL) < 0) {
 +		err = -ENOMEM;
 +		goto free;
 +	}
  
 -			chunk = sctp_make_abort_user(asoc, msg, msg_len);
 -			if (!chunk) {
 -				err = -ENOMEM;
 -				goto out_unlock;
 -			}
 +	if (cmsgs->init) {
 +		struct sctp_initmsg *init = cmsgs->init;
  
 -			pr_debug("%s: aborting association:%p\n",
 -				 __func__, asoc);
 +		if (init->sinit_num_ostreams) {
 +			__u16 outcnt = init->sinit_num_ostreams;
  
 -			sctp_primitive_ABORT(net, asoc, chunk);
 -			err = 0;
 -			goto out_unlock;
 +			asoc->c.sinit_num_ostreams = outcnt;
 +			/* outcnt has been changed, need to re-init stream */
 +			err = sctp_stream_init(&asoc->stream, outcnt, 0,
 +					       GFP_KERNEL);
 +			if (err)
 +				goto free;
  		}
 +
 +		if (init->sinit_max_instreams)
 +			asoc->c.sinit_max_instreams = init->sinit_max_instreams;
 +
 +		if (init->sinit_max_attempts)
 +			asoc->max_init_attempts = init->sinit_max_attempts;
 +
 +		if (init->sinit_max_init_timeo)
 +			asoc->max_init_timeo =
 +				msecs_to_jiffies(init->sinit_max_init_timeo);
  	}
  
 -	/* Do we need to create the association?  */
 -	if (!asoc) {
 -		pr_debug("%s: there is no association yet\n", __func__);
 +	*tp = sctp_assoc_add_peer(asoc, daddr, GFP_KERNEL, SCTP_UNKNOWN);
 +	if (!*tp) {
 +		err = -ENOMEM;
 +		goto free;
 +	}
  
 -		if (sinfo_flags & (SCTP_EOF | SCTP_ABORT)) {
 -			err = -EINVAL;
 -			goto out_unlock;
 -		}
 +	if (!cmsgs->addrs_msg)
 +		return 0;
  
 -		/* Check for invalid stream against the stream counts,
 -		 * either the default or the user specified stream counts.
 -		 */
 -		if (sinfo) {
 -			if (!sinit || !sinit->sinit_num_ostreams) {
 -				/* Check against the defaults. */
 -				if (sinfo->sinfo_stream >=
 -				    sp->initmsg.sinit_num_ostreams) {
 -					err = -EINVAL;
 -					goto out_unlock;
 -				}
 -			} else {
 -				/* Check against the requested.  */
 -				if (sinfo->sinfo_stream >=
 -				    sinit->sinit_num_ostreams) {
 -					err = -EINVAL;
 -					goto out_unlock;
 -				}
 -			}
 -		}
 +	/* sendv addr list parse */
 +	for_each_cmsghdr(cmsg, cmsgs->addrs_msg) {
 +		struct sctp_transport *transport;
 +		struct sctp_association *old;
 +		union sctp_addr _daddr;
 +		int dlen;
  
 -		/*
 -		 * API 3.1.2 bind() - UDP Style Syntax
 -		 * If a bind() or sctp_bindx() is not called prior to a
 -		 * sendmsg() call that initiates a new association, the
 -		 * system picks an ephemeral port and will choose an address
 -		 * set equivalent to binding with a wildcard address.
 -		 */
 -		if (!ep->base.bind_addr.port) {
 -			if (sctp_autobind(sk)) {
 -				err = -EAGAIN;
 -				goto out_unlock;
 -			}
 -		} else {
 -			/*
 -			 * If an unprivileged user inherits a one-to-many
 -			 * style socket with open associations on a privileged
 -			 * port, it MAY be permitted to accept new associations,
 -			 * but it SHOULD NOT be permitted to open new
 -			 * associations.
 -			 */
 -			if (ep->base.bind_addr.port < inet_prot_sock(net) &&
 -			    !ns_capable(net->user_ns, CAP_NET_BIND_SERVICE)) {
 -				err = -EACCES;
 -				goto out_unlock;
 -			}
 -		}
 +		if (cmsg->cmsg_level != IPPROTO_SCTP ||
 +		    (cmsg->cmsg_type != SCTP_DSTADDRV4 &&
 +		     cmsg->cmsg_type != SCTP_DSTADDRV6))
 +			continue;
  
 -		scope = sctp_scope(&to);
 +		daddr = &_daddr;
 +		memset(daddr, 0, sizeof(*daddr));
 +		dlen = cmsg->cmsg_len - sizeof(struct cmsghdr);
 +		if (cmsg->cmsg_type == SCTP_DSTADDRV4) {
 +			if (dlen < sizeof(struct in_addr))
 +				goto free;
 +
 +			dlen = sizeof(struct in_addr);
 +			daddr->v4.sin_family = AF_INET;
 +			daddr->v4.sin_port = htons(asoc->peer.port);
 +			memcpy(&daddr->v4.sin_addr, CMSG_DATA(cmsg), dlen);
 +		} else {
 +			if (dlen < sizeof(struct in6_addr))
 +				goto free;
  
 -		/* Label connection socket for first association 1-to-many
 -		 * style for client sequence socket()->sendmsg(). This
 -		 * needs to be done before sctp_assoc_add_peer() as that will
 -		 * set up the initial packet that needs to account for any
 -		 * security ip options (CIPSO/CALIPSO) added to the packet.
 -		 */
 -		af = sctp_get_af_specific(to.sa.sa_family);
 -		if (!af) {
 -			err = -EINVAL;
 -			goto out_unlock;
 +			dlen = sizeof(struct in6_addr);
 +			daddr->v6.sin6_family = AF_INET6;
 +			daddr->v6.sin6_port = htons(asoc->peer.port);
 +			memcpy(&daddr->v6.sin6_addr, CMSG_DATA(cmsg), dlen);
  		}
 -		err = security_sctp_bind_connect(sk, SCTP_SENDMSG_CONNECT,
 -						 (struct sockaddr *)&to,
 -						 af->sockaddr_len);
 -		if (err < 0)
 -			goto out_unlock;
 +		err = sctp_verify_addr(sk, daddr, sizeof(*daddr));
 +		if (err)
 +			goto free;
  
 -		new_asoc = sctp_association_new(ep, sk, scope, GFP_KERNEL);
 -		if (!new_asoc) {
 -			err = -ENOMEM;
 -			goto out_unlock;
 -		}
 -		asoc = new_asoc;
 -		err = sctp_assoc_set_bind_addr_from_ep(asoc, scope, GFP_KERNEL);
 -		if (err < 0) {
 -			err = -ENOMEM;
 -			goto out_free;
 +		old = sctp_endpoint_lookup_assoc(ep, daddr, &transport);
 +		if (old && old != asoc) {
 +			if (old->state >= SCTP_STATE_ESTABLISHED)
 +				err = -EISCONN;
 +			else
 +				err = -EALREADY;
 +			goto free;
  		}
  
 -		/* If the SCTP_INIT ancillary data is specified, set all
 -		 * the association init values accordingly.
 -		 */
 -		if (sinit) {
 -			if (sinit->sinit_num_ostreams) {
 -				__u16 outcnt = sinit->sinit_num_ostreams;
 -
 -				asoc->c.sinit_num_ostreams = outcnt;
 -				/* outcnt has been changed, so re-init stream */
 -				err = sctp_stream_init(&asoc->stream, outcnt, 0,
 -						       GFP_KERNEL);
 -				if (err)
 -					goto out_free;
 -			}
 -			if (sinit->sinit_max_instreams) {
 -				asoc->c.sinit_max_instreams =
 -					sinit->sinit_max_instreams;
 -			}
 -			if (sinit->sinit_max_attempts) {
 -				asoc->max_init_attempts
 -					= sinit->sinit_max_attempts;
 -			}
 -			if (sinit->sinit_max_init_timeo) {
 -				asoc->max_init_timeo =
 -				 msecs_to_jiffies(sinit->sinit_max_init_timeo);
 -			}
 +		if (sctp_endpoint_is_peeled_off(ep, daddr)) {
 +			err = -EADDRNOTAVAIL;
 +			goto free;
  		}
  
 -		/* Prime the peer's transport structures.  */
 -		transport = sctp_assoc_add_peer(asoc, &to, GFP_KERNEL, SCTP_UNKNOWN);
 +		transport = sctp_assoc_add_peer(asoc, daddr, GFP_KERNEL,
 +						SCTP_UNKNOWN);
  		if (!transport) {
  			err = -ENOMEM;
 -			goto out_free;
 +			goto free;
  		}
  	}