From: Lin Feng Shen <shenlinf@cn.ibm.com>

Functions compat_nfs_svc_trans, compat_nfs_clnt_trans, compat_nfs_exp_trans,
compat_nfs_getfd_trans and compat_nfs_getfs_trans, which are called by
compat_sys_nfsservctl(fs/compat.c), don't handle the return value of
access_ok properly. access_ok return 1 when the addr is valid, and 0
when it's not, but these functions have the reversed understanding. When the
address is valid, they always return -EFAULT to compat_sys_nfsservctl.

An example is to run /usr/sbin/rpc.nfsd(32bit program on Power5). It doesn't
function as expected. strace showes that nfsservctl returns -EFAULT.

The patch fixes this by correcting the error handling on the return value of
access_ok in the five functions. It is created against linux-2.6.17-rc3-git16.

Signed-off-by: Lin Feng Shen <shenlinf@cn.ibm.com>
--- 

--- linux-2.6.17-rc3-git16/fs/compat.c.orig	2006-05-09 09:07:38.000000000 -0500
+++ linux-2.6.17-rc3-git16/fs/compat.c	2006-05-09 09:21:00.000000000 -0500
@@ -2032,101 +2032,96 @@ union compat_nfsctl_res {
 
 static int compat_nfs_svc_trans(struct nfsctl_arg *karg, struct compat_nfsctl_arg __user *arg)
 {
-	int err;
-
-	err = access_ok(VERIFY_READ, &arg->ca32_svc, sizeof(arg->ca32_svc));
-	err |= get_user(karg->ca_version, &arg->ca32_version);
-	err |= __get_user(karg->ca_svc.svc_port, &arg->ca32_svc.svc32_port);
-	err |= __get_user(karg->ca_svc.svc_nthreads, &arg->ca32_svc.svc32_nthreads);
-	return (err) ? -EFAULT : 0;
+	if(!access_ok(VERIFY_READ, &arg->ca32_svc, sizeof(arg->ca32_svc)) ||
+	    get_user(karg->ca_version, &arg->ca32_version) ||
+	    __get_user(karg->ca_svc.svc_port, &arg->ca32_svc.svc32_port) ||
+	    __get_user(karg->ca_svc.svc_nthreads, &arg->ca32_svc.svc32_nthreads))
+		return -EFAULT;
+	return 0;
 }
 
 static int compat_nfs_clnt_trans(struct nfsctl_arg *karg, struct compat_nfsctl_arg __user *arg)
 {
-	int err;
-
-	err = access_ok(VERIFY_READ, &arg->ca32_client, sizeof(arg->ca32_client));
-	err |= get_user(karg->ca_version, &arg->ca32_version);
-	err |= __copy_from_user(&karg->ca_client.cl_ident[0],
+	if(!access_ok(VERIFY_READ, &arg->ca32_client, sizeof(arg->ca32_client)) ||
+	    get_user(karg->ca_version, &arg->ca32_version) ||
+	    __copy_from_user(&karg->ca_client.cl_ident[0],
 			  &arg->ca32_client.cl32_ident[0],
-			  NFSCLNT_IDMAX);
-	err |= __get_user(karg->ca_client.cl_naddr, &arg->ca32_client.cl32_naddr);
-	err |= __copy_from_user(&karg->ca_client.cl_addrlist[0],
+			  NFSCLNT_IDMAX) ||
+	    __get_user(karg->ca_client.cl_naddr, &arg->ca32_client.cl32_naddr) ||
+	    __copy_from_user(&karg->ca_client.cl_addrlist[0],
 			  &arg->ca32_client.cl32_addrlist[0],
-			  (sizeof(struct in_addr) * NFSCLNT_ADDRMAX));
-	err |= __get_user(karg->ca_client.cl_fhkeytype,
-		      &arg->ca32_client.cl32_fhkeytype);
-	err |= __get_user(karg->ca_client.cl_fhkeylen,
-		      &arg->ca32_client.cl32_fhkeylen);
-	err |= __copy_from_user(&karg->ca_client.cl_fhkey[0],
+			  (sizeof(struct in_addr) * NFSCLNT_ADDRMAX)) ||
+	    __get_user(karg->ca_client.cl_fhkeytype,
+		      &arg->ca32_client.cl32_fhkeytype) ||
+	    __get_user(karg->ca_client.cl_fhkeylen,
+		      &arg->ca32_client.cl32_fhkeylen) ||
+	    __copy_from_user(&karg->ca_client.cl_fhkey[0],
 			  &arg->ca32_client.cl32_fhkey[0],
-			  NFSCLNT_KEYMAX);
+			  NFSCLNT_KEYMAX))
+		return -EFAULT;
 
-	return (err) ? -EFAULT : 0;
+	return 0;
 }
 
 static int compat_nfs_exp_trans(struct nfsctl_arg *karg, struct compat_nfsctl_arg __user *arg)
 {
-	int err;
-
-	err = access_ok(VERIFY_READ, &arg->ca32_export, sizeof(arg->ca32_export));
-	err |= get_user(karg->ca_version, &arg->ca32_version);
-	err |= __copy_from_user(&karg->ca_export.ex_client[0],
+	if(!access_ok(VERIFY_READ, &arg->ca32_export, sizeof(arg->ca32_export)) ||
+	    get_user(karg->ca_version, &arg->ca32_version) ||
+	    __copy_from_user(&karg->ca_export.ex_client[0],
 			  &arg->ca32_export.ex32_client[0],
-			  NFSCLNT_IDMAX);
-	err |= __copy_from_user(&karg->ca_export.ex_path[0],
+			  NFSCLNT_IDMAX) ||
+	    __copy_from_user(&karg->ca_export.ex_path[0],
 			  &arg->ca32_export.ex32_path[0],
-			  NFS_MAXPATHLEN);
-	err |= __get_user(karg->ca_export.ex_dev,
-		      &arg->ca32_export.ex32_dev);
-	err |= __get_user(karg->ca_export.ex_ino,
-		      &arg->ca32_export.ex32_ino);
-	err |= __get_user(karg->ca_export.ex_flags,
-		      &arg->ca32_export.ex32_flags);
-	err |= __get_user(karg->ca_export.ex_anon_uid,
-		      &arg->ca32_export.ex32_anon_uid);
-	err |= __get_user(karg->ca_export.ex_anon_gid,
-		      &arg->ca32_export.ex32_anon_gid);
+			  NFS_MAXPATHLEN) ||
+	    __get_user(karg->ca_export.ex_dev,
+		      &arg->ca32_export.ex32_dev) ||
+	    __get_user(karg->ca_export.ex_ino,
+		      &arg->ca32_export.ex32_ino) ||
+	    __get_user(karg->ca_export.ex_flags,
+		      &arg->ca32_export.ex32_flags) ||
+	    __get_user(karg->ca_export.ex_anon_uid,
+		      &arg->ca32_export.ex32_anon_uid) ||
+	    __get_user(karg->ca_export.ex_anon_gid,
+		      &arg->ca32_export.ex32_anon_gid))
+		return -EFAULT;
 	SET_UID(karg->ca_export.ex_anon_uid, karg->ca_export.ex_anon_uid);
 	SET_GID(karg->ca_export.ex_anon_gid, karg->ca_export.ex_anon_gid);
 
-	return (err) ? -EFAULT : 0;
+	return 0;
 }
 
 static int compat_nfs_getfd_trans(struct nfsctl_arg *karg, struct compat_nfsctl_arg __user *arg)
 {
-	int err;
-
-	err = access_ok(VERIFY_READ, &arg->ca32_getfd, sizeof(arg->ca32_getfd));
-	err |= get_user(karg->ca_version, &arg->ca32_version);
-	err |= __copy_from_user(&karg->ca_getfd.gd_addr,
+	if(!access_ok(VERIFY_READ, &arg->ca32_getfd, sizeof(arg->ca32_getfd)) ||
+	    get_user(karg->ca_version, &arg->ca32_version) ||
+	    __copy_from_user(&karg->ca_getfd.gd_addr,
 			  &arg->ca32_getfd.gd32_addr,
-			  (sizeof(struct sockaddr)));
-	err |= __copy_from_user(&karg->ca_getfd.gd_path,
+			  (sizeof(struct sockaddr))) ||
+	    __copy_from_user(&karg->ca_getfd.gd_path,
 			  &arg->ca32_getfd.gd32_path,
-			  (NFS_MAXPATHLEN+1));
-	err |= __get_user(karg->ca_getfd.gd_version,
-		      &arg->ca32_getfd.gd32_version);
+			  (NFS_MAXPATHLEN+1)) ||
+	    __get_user(karg->ca_getfd.gd_version,
+		      &arg->ca32_getfd.gd32_version))
+		return -EFAULT;
 
-	return (err) ? -EFAULT : 0;
+	return 0;
 }
 
 static int compat_nfs_getfs_trans(struct nfsctl_arg *karg, struct compat_nfsctl_arg __user *arg)
 {
-	int err;
-
-	err = access_ok(VERIFY_READ, &arg->ca32_getfs, sizeof(arg->ca32_getfs));
-	err |= get_user(karg->ca_version, &arg->ca32_version);
-	err |= __copy_from_user(&karg->ca_getfs.gd_addr,
+	if(!access_ok(VERIFY_READ, &arg->ca32_getfs, sizeof(arg->ca32_getfs)) ||
+	    get_user(karg->ca_version, &arg->ca32_version) ||
+	    __copy_from_user(&karg->ca_getfs.gd_addr,
 			  &arg->ca32_getfs.gd32_addr,
-			  (sizeof(struct sockaddr)));
-	err |= __copy_from_user(&karg->ca_getfs.gd_path,
+			  (sizeof(struct sockaddr))) ||
+	    __copy_from_user(&karg->ca_getfs.gd_path,
 			  &arg->ca32_getfs.gd32_path,
-			  (NFS_MAXPATHLEN+1));
-	err |= __get_user(karg->ca_getfs.gd_maxlen,
-		      &arg->ca32_getfs.gd32_maxlen);
+			  (NFS_MAXPATHLEN+1)) ||
+	    __get_user(karg->ca_getfs.gd_maxlen,
+		      &arg->ca32_getfs.gd32_maxlen))
+		return -EFAULT;
 
-	return (err) ? -EFAULT : 0;
+	return 0;
 }
 
 /* This really doesn't need translations, we are only passing