svn commit: r265896 - head/sys/kern

[Jilles Tjoelker]

Author: jilles
Date: Sun May 11 21:21:14 2014
New Revision: 265896
URL: http://svnweb.freebsd.org/changeset/base/265896

Log:
  accept(),accept4(): Don't set *addrlen = 0 on [ECONNABORTED].
  
  If the underlying protocol reported an error (e.g. because a connection was
  closed while waiting in the queue), this error was also indicated by
  returning a zero-length address. For all other kinds of errors (e.g.
  [EAGAIN], [ENFILE], [EMFILE]), *addrlen is unmodified and there are
  successful cases where a zero-length address is returned (e.g. a connection
  from an unbound Unix-domain socket), so this error indication is not
  reliable.
  
  As reported in Austin Group bug #836, modifying *addrlen on error may cause
  subtle bugs if applications retry the call without resetting *addrlen.

Modified:
  head/sys/kern/uipc_syscalls.c

Modified: head/sys/kern/uipc_syscalls.c
==============================================================================
--- head/sys/kern/uipc_syscalls.c	Sun May 11 21:07:00 2014	(r265895)
+++ head/sys/kern/uipc_syscalls.c	Sun May 11 21:21:14 2014	(r265896)
@@ -414,14 +414,8 @@ accept1(td, s, uname, anamelen, flags)
 
 	error = kern_accept4(td, s, &name, &namelen, flags, &fp);
 
-	/*
-	 * return a namelen of zero for older code which might
-	 * ignore the return value from accept.
-	 */
-	if (error != 0) {
-		(void) copyout(&namelen, anamelen, sizeof(*anamelen));
+	if (error != 0)
 		return (error);
-	}
 
 	if (error == 0 && uname != NULL) {
 #ifdef COMPAT_OLDSOCK
@@ -555,15 +549,8 @@ kern_accept4(struct thread *td, int s, s
 	(void) fo_ioctl(nfp, FIOASYNC, &tmp, td->td_ucred, td);
 	sa = 0;
 	error = soaccept(so, &sa);
-	if (error != 0) {
-		/*
-		 * return a namelen of zero for older code which might
-		 * ignore the return value from accept.
-		 */
-		if (name)
-			*namelen = 0;
+	if (error != 0)
 		goto noconnection;
-	}
 	if (sa == NULL) {
 		if (name)
 			*namelen = 0;