better nfsrv_access() control, from netbsd

1 files changed, 28 insertions, 24 deletions

diff --git a/sys/nfs/nfs_serv.c b/sys/nfs/nfs_serv.c
index 82ccc51401d..ba8b2d891f2 100644
--- a/sys/nfs/nfs_serv.c
+++ b/sys/nfs/nfs_serv.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: nfs_serv.c,v 1.7 1996/11/08 23:20:14 niklas Exp $	*/
+/*	$OpenBSD: nfs_serv.c,v 1.8 1996/12/14 15:36:50 deraadt Exp $	*/
 /*	$NetBSD: nfs_serv.c,v 1.25 1996/03/02 15:55:52 jtk Exp $	*/
 
 /*
@@ -132,7 +132,7 @@ nfsrv3_access(nfsd, slp, procp, mrq)
 	}
 	nfsmode = fxdr_unsigned(u_int32_t, *tl);
 	if ((nfsmode & NFSV3ACCESS_READ) &&
-		nfsrv_access(vp, VREAD, cred, rdonly, procp))
+		nfsrv_access(vp, VREAD, cred, rdonly, procp, 0))
 		nfsmode &= ~NFSV3ACCESS_READ;
 	if (vp->v_type == VDIR)
 		testmode = (NFSV3ACCESS_MODIFY | NFSV3ACCESS_EXTEND |
@@ -140,14 +140,14 @@ nfsrv3_access(nfsd, slp, procp, mrq)
 	else
 		testmode = (NFSV3ACCESS_MODIFY | NFSV3ACCESS_EXTEND);
 	if ((nfsmode & testmode) &&
-		nfsrv_access(vp, VWRITE, cred, rdonly, procp))
+		nfsrv_access(vp, VWRITE, cred, rdonly, procp, 0))
 		nfsmode &= ~testmode;
 	if (vp->v_type == VDIR)
 		testmode = NFSV3ACCESS_LOOKUP;
 	else
 		testmode = NFSV3ACCESS_EXECUTE;
 	if ((nfsmode & testmode) &&
-		nfsrv_access(vp, VEXEC, cred, rdonly, procp))
+		nfsrv_access(vp, VEXEC, cred, rdonly, procp, 0))
 		nfsmode &= ~testmode;
 	getret = VOP_GETATTR(vp, &va, cred, procp);
 	vput(vp);
@@ -315,7 +315,7 @@ nfsrv_setattr(nfsd, slp, procp, mrq)
 			error = EISDIR;
 			goto out;
 		} else if ((error = nfsrv_access(vp, VWRITE, cred, rdonly,
-			procp)) != 0)
+			procp, 0)) != 0)
 			goto out;
 	}
 	error = VOP_SETATTR(vp, &va, cred, procp);
@@ -571,8 +571,8 @@ nfsrv_read(nfsd, slp, procp, mrq)
 	}
 	if (!error) {
 	    nqsrv_getl(vp, ND_READ);
-	    if ((error = nfsrv_access(vp, VREAD, cred, rdonly, procp)) != 0)
-		error = nfsrv_access(vp, VEXEC, cred, rdonly, procp);
+	    if ((error = nfsrv_access(vp, VREAD, cred, rdonly, procp, 1)) != 0)
+		error = nfsrv_access(vp, VEXEC, cred, rdonly, procp, 1);
 	}
 	getret = VOP_GETATTR(vp, &va, cred, procp);
 	if (!error)
@@ -785,7 +785,7 @@ nfsrv_write(nfsd, slp, procp, mrq)
 	}
 	if (!error) {
 		nqsrv_getl(vp, ND_WRITE);
-		error = nfsrv_access(vp, VWRITE, cred, rdonly, procp);
+		error = nfsrv_access(vp, VWRITE, cred, rdonly, procp, 1);
 	}
 	if (error) {
 		vput(vp);
@@ -1050,7 +1050,7 @@ loop1:
 		    vp = NULL;
 		if (!error) {
 		    nqsrv_getl(vp, ND_WRITE);
-		    error = nfsrv_access(vp, VWRITE, cred, rdonly, procp);
+		    error = nfsrv_access(vp, VWRITE, cred, rdonly, procp, 1);
 		}
     
 		if (nfsd->nd_stable == NFSV3WRITE_UNSTABLE)
@@ -1391,7 +1391,7 @@ nfsrv_create(nfsd, slp, procp, mrq)
 		VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
 		if (va.va_size != -1) {
 			error = nfsrv_access(vp, VWRITE, cred,
-			    (nd.ni_cnd.cn_flags & RDONLY), procp);
+			    (nd.ni_cnd.cn_flags & RDONLY), procp, 0);
 			if (!error) {
 				nqsrv_getl(vp, ND_WRITE);
 				tempsize = va.va_size;
@@ -2446,7 +2446,7 @@ nfsrv_readdir(nfsd, slp, procp, mrq)
 #endif
 	}
 	if (!error)
-		error = nfsrv_access(vp, VEXEC, cred, rdonly, procp);
+		error = nfsrv_access(vp, VEXEC, cred, rdonly, procp, 0);
 	if (error) {
 		vput(vp);
 		nfsm_reply(NFSX_POSTOPATTR(v3));
@@ -2713,7 +2713,7 @@ nfsrv_readdirplus(nfsd, slp, procp, mrq)
 #endif
 	if (!error) {
 		nqsrv_getl(vp, ND_READ);
-		error = nfsrv_access(vp, VEXEC, cred, rdonly, procp);
+		error = nfsrv_access(vp, VEXEC, cred, rdonly, procp, 0);
 	}
 	if (error) {
 		vput(vp);
@@ -3285,18 +3285,20 @@ nfsrv_noop(nfsd, slp, procp, mrq)
  * refer to files already opened by a Unix client. You cannot just use
  * vn_writechk() and VOP_ACCESS() for two reasons.
  * 1 - You must check for exported rdonly as well as MNT_RDONLY for the write case
- * 2 - The owner is to be given access irrespective of mode bits so that
- *     processes that chmod after opening a file don't break. I don't like
- *     this because it opens a security hole, but since the nfs server opens
- *     a security hole the size of a barn door anyhow, what the heck.
+ * 2 - The owner is to be given access irrespective of mode bits for some
+ *     operations, so that processes that chmod after opening a file don't
+ *     break. I don't like this because it opens a security hole, but since
+ *     the nfs server opens a security hole the size of a barn door anyhow,
+ *     what the heck.
  */
 int
-nfsrv_access(vp, flags, cred, rdonly, p)
+nfsrv_access(vp, flags, cred, rdonly, p, override)
 	register struct vnode *vp;
 	int flags;
 	register struct ucred *cred;
 	int rdonly;
 	struct proc *p;
+	int override;
 {
 	struct vattr vattr;
 	int error;
@@ -3325,11 +3327,13 @@ nfsrv_access(vp, flags, cred, rdonly, p)
 		if ((vp->v_flag & VTEXT) && !vnode_pager_uncache(vp))
 			return (ETXTBSY);
 	}
-	error = VOP_GETATTR(vp, &vattr, cred, p);
-	if (error)
-		return (error);
-	if ((error = VOP_ACCESS(vp, flags, cred, p)) != 0 &&
-	    cred->cr_uid != vattr.va_uid)
-		return (error);
-	return (0);
+	error = VOP_ACCESS(vp, flags, cred, p);
+	/*
+	 * Allow certain operations for the owner (reads and writes
+	 * on files that are already open).
+	 */
+	if (override && (error == EPERM || error == EACCES) &&
+	    cred->cr_uid == vattr.va_uid)
+		error = 0;
+	return error;
 }