From: Cyrill Gorcunov <gorcunov@gmail.com>
Subject: [PATCH] NFS - fix possible NULL pointer dereference

kstrndup and kstrdup may return NULL so we should be
ready for a such situation

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>

---

--- a/fs/nfs/super.c	Wed Mar 05 07:33:54 2008
+++ a/fs/nfs/super.c	Thu Apr 17 11:10:34 2008
@@ -1211,6 +1211,8 @@ static int nfs_validate_mount_data(void 
 			args->nfs_server.protocol = XPRT_TRANSPORT_UDP;
 		/* N.B. caller will free nfs_server.hostname in all cases */
 		args->nfs_server.hostname = kstrdup(data->hostname, GFP_KERNEL);
+		if (!args->nfs_server.hostname)
+			goto out_nomem;
 		args->namlen		= data->namlen;
 		args->bsize		= data->bsize;
 		args->auth_flavors[0]	= data->pseudoflavor;
@@ -1233,6 +1235,8 @@ static int nfs_validate_mount_data(void 
 		len = c - dev_name;
 		/* N.B. caller will free nfs_server.hostname in all cases */
 		args->nfs_server.hostname = kstrndup(dev_name, len, GFP_KERNEL);
+		if (!args->nfs_server.hostname)
+			goto out_nomem;
 
 		c++;
 		if (strlen(c) > NFS_MAXPATHLEN)
@@ -1280,6 +1284,10 @@ out_no_address:
 	dfprintk(MOUNT, "NFS: mount program didn't pass remote address\n");
 	return -EINVAL;
 
+out_nomem:
+	dfprintk(MOUNT, "NFS: not enough memory to duplicate string\n");
+	return -ENOMEM;
+
 out_invalid_fh:
 	dfprintk(MOUNT, "NFS: invalid root filehandle\n");
 	return -EINVAL;
@@ -1797,12 +1805,15 @@ static int nfs4_validate_mount_data(void
 			return -ENAMETOOLONG;
 		/* N.B. caller will free nfs_server.hostname in all cases */
 		args->nfs_server.hostname = kstrndup(dev_name, len, GFP_KERNEL);
-
+		if (!args->nfs_server.hostname)
+			goto out_nomem;
 		c++;			/* step over the ':' */
 		len = strlen(c);
 		if (len > NFS4_MAXPATHLEN)
 			return -ENAMETOOLONG;
 		args->nfs_server.export_path = kstrndup(c, len, GFP_KERNEL);
+		if (!args->nfs_server.export_path)
+			goto out_nomem;
 
 		dprintk("NFS: MNTPATH: '%s'\n", args->nfs_server.export_path);
 
@@ -1827,6 +1838,10 @@ out_inval_auth:
 out_no_address:
 	dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
 	return -EINVAL;
+
+out_nomem:
+	dfprintk(MOUNT, "NFS4: not enough memory to duplicate string\n");
+	return -ENOMEM;
 
 out_no_client_address:
 	dfprintk(MOUNT, "NFS4: mount program didn't pass callback address\n");