Merge back devfs changes from the mpsafetty branch.

In the mpsafetty branch, PTY's are allocated through the posix_openpt()
system call. The controller side of a PTY now uses its own file
descriptor type (just like sockets, vnodes, pipes, etc).

To remain compatible with existing FreeBSD and Linux C libraries, we can
still create PTY's by opening /dev/ptmx or /dev/ptyXX. These nodes
implement d_fdopen(). Devfs has been slightly changed here, to allow
finit() to be called from d_fdopen().

The routine grantpt() has also been moved into the kernel. This routine
is a little odd, because it needs to bypass standard UNIX permissions.
It needs to change the owner/group/mode of the slave device node, which
may often not be possible. The old implementation solved this by
spawning a setuid utility.

When VOP_SETATTR() is called with NOCRED, devfs_setattr() dereferences
ap->a_cred, causing a kernel panic. Change the de_{uid,gid,mode} code to
allow changes when a->a_cred is set to NOCRED.

Approved by:	philip (mentor)

1 files changed, 6 insertions, 6 deletions

diff --git a/sys/fs/devfs/devfs_vnops.c b/sys/fs/devfs/devfs_vnops.c
index 80f2dba..724f082 100644
--- a/sys/fs/devfs/devfs_vnops.c
+++ b/sys/fs/devfs/devfs_vnops.c
@@ -891,9 +891,8 @@ devfs_open(struct vop_open_args *ap)
 	if(fp == NULL)
 		return (error);
 #endif
-	KASSERT(fp->f_ops == &badfileops,
-	     ("Could not vnode bypass device on fdops %p", fp->f_ops));
-	finit(fp, fp->f_flag, DTYPE_VNODE, dev, &devfs_ops_f);
+	if (fp->f_ops == &badfileops)
+		finit(fp, fp->f_flag, DTYPE_VNODE, dev, &devfs_ops_f);
 	return (error);
 }
 
@@ -1265,8 +1264,9 @@ devfs_setattr(struct vop_setattr_args *ap)
 	else
 		gid = vap->va_gid;
 	if (uid != de->de_uid || gid != de->de_gid) {
-		if ((ap->a_cred->cr_uid != de->de_uid) || uid != de->de_uid ||
-		    (gid != de->de_gid && !groupmember(gid, ap->a_cred))) {
+		if (ap->a_cred != NOCRED &&
+		    (ap->a_cred->cr_uid != de->de_uid || uid != de->de_uid ||
+		    (gid != de->de_gid && !groupmember(gid, ap->a_cred)))) {
 			error = priv_check(ap->a_td, PRIV_VFS_CHOWN);
 			if (error)
 				return (error);
@@ -1277,7 +1277,7 @@ devfs_setattr(struct vop_setattr_args *ap)
 	}
 
 	if (vap->va_mode != (mode_t)VNOVAL) {
-		if (ap->a_cred->cr_uid != de->de_uid) {
+		if (ap->a_cred != NOCRED && ap->a_cred->cr_uid != de->de_uid) {
 			error = priv_check(ap->a_td, PRIV_VFS_ADMIN);
 			if (error)
 				return (error);