NFS: Client implementation of Labeled-NFS

This patch implements the client transport and handling support for labeled
NFS. The patch adds two functions to encode and decode the security label
recommended attribute which makes use of the LSM hooks added earlier. It also
adds code to grab the label from the file attribute structures and encode the
label to be sent back to the server.
Acked-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Matthew N. Dodd <Matthew.Dodd@sparta.com>
Signed-off-by: Miguel Rodel Felipe <Rodel_FM@dsi.a-star.edu.sg>
Signed-off-by: Phua Eu Gene <PHUA_Eu_Gene@dsi.a-star.edu.sg>
Signed-off-by: Khin Mi Mi Aung <Mi_Mi_AUNG@dsi.a-star.edu.sg>
Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/dir.c

@@ -435,6 +435,7 @@ void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry)
 	struct dentry *alias;
 	struct inode *dir = parent->d_inode;
 	struct inode *inode;
+	int status;
 
 	if (filename.name[0] == '.') {
 		if (filename.len == 1)
@@ -447,7 +448,9 @@ void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry)
 	dentry = d_lookup(parent, &filename);
 	if (dentry != NULL) {
 		if (nfs_same_file(dentry, entry)) {
-			nfs_refresh_inode(dentry->d_inode, entry->fattr);
+			status = nfs_refresh_inode(dentry->d_inode, entry->fattr);
+			if (!status)
+				nfs_setsecurity(dentry->d_inode, entry->fattr, entry->label);
 			goto out;
 		} else {
 			if (d_invalidate(dentry) != 0)
@@ -1103,6 +1106,8 @@ static int nfs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
 	if ((error = nfs_refresh_inode(inode, fattr)) != 0)
 		goto out_bad;
 
+	nfs_setsecurity(inode, fattr, label);
+
 	nfs_free_fattr(fattr);
 	nfs_free_fhandle(fhandle);
 	nfs4_label_free(label);

fs/nfs/inode.c

@@ -162,11 +162,19 @@ static void nfs_zap_caches_locked(struct inode *inode)
 
 	memset(NFS_I(inode)->cookieverf, 0, sizeof(NFS_I(inode)->cookieverf));
 	if (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)) {
-		nfsi->cache_validity |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA|NFS_INO_INVALID_ACCESS|NFS_INO_INVALID_ACL|NFS_INO_REVAL_PAGECACHE;
 		nfs_fscache_invalidate(inode);
-	} else {
-		nfsi->cache_validity |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ACCESS|NFS_INO_INVALID_ACL|NFS_INO_REVAL_PAGECACHE;
-	}
+		nfsi->cache_validity |= NFS_INO_INVALID_ATTR
+					| NFS_INO_INVALID_LABEL
+					| NFS_INO_INVALID_DATA
+					| NFS_INO_INVALID_ACCESS
+					| NFS_INO_INVALID_ACL
+					| NFS_INO_REVAL_PAGECACHE;
+	} else
+		nfsi->cache_validity |= NFS_INO_INVALID_ATTR
+					| NFS_INO_INVALID_LABEL
+					| NFS_INO_INVALID_ACCESS
+					| NFS_INO_INVALID_ACL
+					| NFS_INO_REVAL_PAGECACHE;
 }
 
 void nfs_zap_caches(struct inode *inode)
@@ -258,6 +266,32 @@ nfs_init_locked(struct inode *inode, void *opaque)
 }
 
 #ifdef CONFIG_NFS_V4_SECURITY_LABEL
+void nfs_setsecurity(struct inode *inode, struct nfs_fattr *fattr,
+					struct nfs4_label *label)
+{
+	int error;
+
+	if (label == NULL)
+		return;
+
+	if (nfs_server_capable(inode, NFS_CAP_SECURITY_LABEL) == 0)
+		return;
+
+	if (NFS_SERVER(inode)->nfs_client->cl_minorversion < 2)
+		return;
+
+	if ((fattr->valid & NFS_ATTR_FATTR_V4_SECURITY_LABEL) && inode->i_security) {
+		error = security_inode_notifysecctx(inode, label->label,
+				label->len);
+		if (error)
+			printk(KERN_ERR "%s() %s %d "
+					"security_inode_notifysecctx() %d\n",
+					__func__,
+					(char *)label->label,
+					label->len, error);
+	}
+}
+
 struct nfs4_label *nfs4_label_alloc(struct nfs_server *server, gfp_t flags)
 {
 	struct nfs4_label *label = NULL;
@@ -283,7 +317,13 @@ struct nfs4_label *nfs4_label_alloc(struct nfs_server *server, gfp_t flags)
 	return label;
 }
 EXPORT_SYMBOL_GPL(nfs4_label_alloc);
+#else
+void inline nfs_setsecurity(struct inode *inode, struct nfs_fattr *fattr,
+					struct nfs4_label *label)
+{
+}
 #endif
+EXPORT_SYMBOL_GPL(nfs_setsecurity);
 
 /*
  * This is our front-end to iget that looks up inodes by file handle
@@ -412,6 +452,9 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr, st
 			 */
 			inode->i_blocks = nfs_calc_block_size(fattr->du.nfs3.used);
 		}
+
+		nfs_setsecurity(inode, fattr, label);
+
 		nfsi->attrtimeo = NFS_MINATTRTIMEO(inode);
 		nfsi->attrtimeo_timestamp = now;
 		nfsi->access_cache = RB_ROOT;
@@ -421,6 +464,7 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr, st
 		unlock_new_inode(inode);
 	} else
 		nfs_refresh_inode(inode, fattr);
+		nfs_setsecurity(inode, fattr, label);
 	dprintk("NFS: nfs_fhget(%s/%Ld fh_crc=0x%08x ct=%d)\n",
 		inode->i_sb->s_id,
 		(long long)NFS_FILEID(inode),
@@ -477,7 +521,7 @@ nfs_setattr(struct dentry *dentry, struct iattr *attr)
 		NFS_PROTO(inode)->return_delegation(inode);
 	error = NFS_PROTO(inode)->setattr(dentry, fattr, attr);
 	if (error == 0)
-		nfs_refresh_inode(inode, fattr);
+		error = nfs_refresh_inode(inode, fattr);
 	nfs_free_fattr(fattr);
 out:
 	return error;
@@ -901,7 +945,8 @@ static int nfs_attribute_cache_expired(struct inode *inode)
  */
 int nfs_revalidate_inode(struct nfs_server *server, struct inode *inode)
 {
-	if (!(NFS_I(inode)->cache_validity & NFS_INO_INVALID_ATTR)
+	if (!(NFS_I(inode)->cache_validity &
+			(NFS_INO_INVALID_ATTR|NFS_INO_INVALID_LABEL))
 			&& !nfs_attribute_cache_expired(inode))
 		return NFS_STALE(inode) ? -ESTALE : 0;
 	return __nfs_revalidate_inode(server, inode);
@@ -1281,6 +1326,7 @@ int nfs_post_op_update_inode(struct inode *inode, struct nfs_fattr *fattr)
 	spin_lock(&inode->i_lock);
 	status = nfs_post_op_update_inode_locked(inode, fattr);
 	spin_unlock(&inode->i_lock);
+
 	return status;
 }
 EXPORT_SYMBOL_GPL(nfs_post_op_update_inode);
@@ -1521,7 +1567,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
 		inode->i_blocks = fattr->du.nfs2.blocks;
 
 	/* Update attrtimeo value if we're out of the unstable period */
-	if (invalid & NFS_INO_INVALID_ATTR) {
+	if (invalid & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_LABEL)) {
 		nfs_inc_stats(inode, NFSIOS_ATTRINVALIDATE);
 		nfsi->attrtimeo = NFS_MINATTRTIMEO(inode);
 		nfsi->attrtimeo_timestamp = now;
@@ -1534,6 +1580,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
 		}
 	}
 	invalid &= ~NFS_INO_INVALID_ATTR;
+	invalid &= ~NFS_INO_INVALID_LABEL;
 	/* Don't invalidate the data if we were to blame */
 	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)
 				|| S_ISLNK(inode->i_mode)))

fs/nfs/super.c

@@ -2417,8 +2417,21 @@ static int nfs_bdi_register(struct nfs_server *server)
 int nfs_set_sb_security(struct super_block *s, struct dentry *mntroot,
 			struct nfs_mount_info *mount_info)
 {
-	return security_sb_set_mnt_opts(s, &mount_info->parsed->lsm_opts,
-								0, NULL);
+	int error;
+	unsigned long kflags = 0, kflags_out = 0;
+	if (NFS_SB(s)->caps & NFS_CAP_SECURITY_LABEL)
+		kflags |= SECURITY_LSM_NATIVE_LABELS;
+
+	error = security_sb_set_mnt_opts(s, &mount_info->parsed->lsm_opts,
+						kflags, &kflags_out);
+	if (error)
+		goto err;
+
+	if (NFS_SB(s)->caps & NFS_CAP_SECURITY_LABEL &&
+		!(kflags_out & SECURITY_LSM_NATIVE_LABELS))
+		NFS_SB(s)->caps &= ~NFS_CAP_SECURITY_LABEL;
+err:
+	return error;
 }
 EXPORT_SYMBOL_GPL(nfs_set_sb_security);
 

include/linux/nfs_fs.h

@@ -207,6 +207,7 @@ struct nfs_inode {
 #define NFS_INO_INVALID_ACL	0x0010		/* cached acls are invalid */
 #define NFS_INO_REVAL_PAGECACHE	0x0020		/* must revalidate pagecache */
 #define NFS_INO_REVAL_FORCED	0x0040		/* force revalidation ignoring a delegation */
+#define NFS_INO_INVALID_LABEL	0x0080		/* cached label is invalid */
 
 /*
  * Bit offsets in flags field
@@ -352,6 +353,8 @@ extern int __nfs_revalidate_inode(struct nfs_server *, struct inode *);
 extern int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping);
 extern int nfs_setattr(struct dentry *, struct iattr *);
 extern void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr);
+extern void nfs_setsecurity(struct inode *inode, struct nfs_fattr *fattr,
+				struct nfs4_label *label);
 extern struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ctx);
 extern void put_nfs_open_context(struct nfs_open_context *ctx);
 extern struct nfs_open_context *nfs_find_open_context(struct inode *inode, struct rpc_cred *cred, fmode_t mode);

include/linux/nfs_fs_sb.h

@@ -146,6 +146,11 @@ struct nfs_server {
 	u32			attr_bitmask[3];/* V4 bitmask representing the set
 						   of attributes supported on this
 						   filesystem */
+	u32			attr_bitmask_nl[3];
+						/* V4 bitmask representing the
+						   set of attributes supported
+						   on this filesystem excluding
+						   the label support bit. */
 	u32			cache_consistency_bitmask[3];
 						/* V4 bitmask representing the subset
 						   of change attribute, size, ctime

security/selinux/hooks.c

@@ -2908,7 +2908,10 @@ static void selinux_inode_post_setxattr(struct dentry *dentry, const char *name,
 		return;
 	}
 
+	isec->sclass = inode_mode_to_security_class(inode->i_mode);
 	isec->sid = newsid;
+	isec->initialized = 1;
+
 	return;
 }
 
@@ -2996,6 +2999,7 @@ static int selinux_inode_setsecurity(struct inode *inode, const char *name,
 	if (rc)
 		return rc;
 
+	isec->sclass = inode_mode_to_security_class(inode->i_mode);
 	isec->sid = newsid;
 	isec->initialized = 1;
 	return 0;