d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fix a deadlock in the getpeername() method for UNIX domain sockets.

Browse Source 
Instead of locking the local unp followed by the remote unp, use the same
locking model as accept() and read lock the global link lock followed by
the remote unp while fetching the remote sockaddr.

Reported by:	Mel Flynn  mel.flynn of mailing.thruhere.net
Reviewed by:	rwatson
MFC after:	1 week
This commit is contained in:
John Baldwin 2009-06-18 20:56:22 +00:00
parent f06a3a36ac
commit afd9f91c63
1 changed files with 4 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
sys/kern/uipc_usrreq.c
View File

@ -671,7 +671,7 @@ uipc_peeraddr(struct socket *so, struct sockaddr **nam)
KASSERT(unp != NULL, ("uipc_peeraddr: unp == NULL"));
*nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
UNP_PCB_LOCK(unp);
UNP_LINK_RLOCK();
/*
* XXX: It seems that this test always fails even when connection is
* established. So, this else clause is added as workaround to
@ -681,7 +681,7 @@ uipc_peeraddr(struct socket *so, struct sockaddr **nam)
if (unp2 != NULL) {
UNP_PCB_LOCK(unp2);
if (unp2->unp_addr != NULL)
sa = (struct sockaddr *) unp->unp_conn->unp_addr;
sa = (struct sockaddr *) unp2->unp_addr;
else
sa = &sun_noname;
bcopy(sa, *nam, sa->sa_len);
@ -690,7 +690,7 @@ uipc_peeraddr(struct socket *so, struct sockaddr **nam)
sa = &sun_noname;
bcopy(sa, *nam, sa->sa_len);
}
UNP_PCB_UNLOCK(unp);
UNP_LINK_RUNLOCK();
return (0);
}
@ -850,7 +850,7 @@ uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
* return the slightly counter-intuitive but otherwise
* correct error that the socket is not connected.
*
* Locking here must be done carefully: the inkage lock
* Locking here must be done carefully: the linkage lock
* prevents interconnections between unpcbs from changing, so
* we can traverse from unp to unp2 without acquiring unp's
* lock. Socket buffer locks follow unpcb locks, so we can