[v2,4/6] LSM: lsm_context in security_dentry_init_security

diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 2508aa8950b7..c9fad8c825dd 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -1133,8 +1133,7 @@  struct ceph_acl_sec_ctx {
 	void *acl;
 #endif
 #ifdef CONFIG_CEPH_FS_SECURITY_LABEL
-	void *sec_ctx;
-	u32 sec_ctxlen;
+	struct lsm_context lsmctx;
 #endif
 #ifdef CONFIG_FS_ENCRYPTION
 	struct ceph_fscrypt_auth *fscrypt_auth;
diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index f7996770cc2c..0b9e1f385d31 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -1383,8 +1383,7 @@  int ceph_security_init_secctx(struct dentry *dentry, umode_t mode,
 	int err;
 
 	err = security_dentry_init_security(dentry, mode, &dentry->d_name,
-					    &name, &as_ctx->sec_ctx,
-					    &as_ctx->sec_ctxlen);
+					    &name, &as_ctx->lsmctx);
 	if (err < 0) {
 		WARN_ON_ONCE(err != -EOPNOTSUPP);
 		err = 0; /* do nothing */
@@ -1409,7 +1408,7 @@  int ceph_security_init_secctx(struct dentry *dentry, umode_t mode,
 	 */
 	name_len = strlen(name);
 	err = ceph_pagelist_reserve(pagelist,
-				    4 * 2 + name_len + as_ctx->sec_ctxlen);
+				    4 * 2 + name_len + as_ctx->lsmctx.len);
 	if (err)
 		goto out;
 
@@ -1432,8 +1431,9 @@  int ceph_security_init_secctx(struct dentry *dentry, umode_t mode,
 	ceph_pagelist_encode_32(pagelist, name_len);
 	ceph_pagelist_append(pagelist, name, name_len);
 
-	ceph_pagelist_encode_32(pagelist, as_ctx->sec_ctxlen);
-	ceph_pagelist_append(pagelist, as_ctx->sec_ctx, as_ctx->sec_ctxlen);
+	ceph_pagelist_encode_32(pagelist, as_ctx->lsmctx.len);
+	ceph_pagelist_append(pagelist, as_ctx->lsmctx.context,
+			     as_ctx->lsmctx.len);
 
 	err = 0;
 out:
@@ -1446,16 +1446,12 @@  int ceph_security_init_secctx(struct dentry *dentry, umode_t mode,
 
 void ceph_release_acl_sec_ctx(struct ceph_acl_sec_ctx *as_ctx)
 {
-#ifdef CONFIG_CEPH_FS_SECURITY_LABEL
-	struct lsm_context scaff; /* scaffolding */
-#endif
 #ifdef CONFIG_CEPH_FS_POSIX_ACL
 	posix_acl_release(as_ctx->acl);
 	posix_acl_release(as_ctx->default_acl);
 #endif
 #ifdef CONFIG_CEPH_FS_SECURITY_LABEL
-	lsmcontext_init(&scaff, as_ctx->sec_ctx, as_ctx->sec_ctxlen, 0);
-	security_release_secctx(&scaff);
+	security_release_secctx(&as_ctx->lsmctx);
 #endif
 #ifdef CONFIG_FS_ENCRYPTION
 	kfree(as_ctx->fscrypt_auth);
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 54104dd48af7..eea4d0d27ce1 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -466,29 +466,29 @@  static int get_security_context(struct dentry *entry, umode_t mode,
 {
 	struct fuse_secctx *fctx;
 	struct fuse_secctx_header *header;
-	void *ctx = NULL, *ptr;
-	u32 ctxlen, total_len = sizeof(*header);
+	struct lsm_context lsmctx = { };
+	void *ptr;
+	u32 total_len = sizeof(*header);
 	int err, nr_ctx = 0;
-	const char *name;
+	const char *name = NULL;
 	size_t namelen;
 
 	err = security_dentry_init_security(entry, mode, &entry->d_name,
-					    &name, &ctx, &ctxlen);
-	if (err) {
-		if (err != -EOPNOTSUPP)
-			goto out_err;
-		/* No LSM is supporting this security hook. Ignore error */
-		ctxlen = 0;
-		ctx = NULL;
-	}
+					    &name, &lsmctx);
+
+	/* If no LSM is supporting this security hook ignore error */
+	if (err && err != -EOPNOTSUPP)
+		goto out_err;
 
-	if (ctxlen) {
+	if (lsmctx.len) {
 		nr_ctx = 1;
 		namelen = strlen(name) + 1;
 		err = -EIO;
-		if (WARN_ON(namelen > XATTR_NAME_MAX + 1 || ctxlen > S32_MAX))
+		if (WARN_ON(namelen > XATTR_NAME_MAX + 1 ||
+		    lsmctx.len > S32_MAX))
 			goto out_err;
-		total_len += FUSE_REC_ALIGN(sizeof(*fctx) + namelen + ctxlen);
+		total_len += FUSE_REC_ALIGN(sizeof(*fctx) + namelen +
+					    lsmctx.len);
 	}
 
 	err = -ENOMEM;
@@ -501,19 +501,20 @@  static int get_security_context(struct dentry *entry, umode_t mode,
 	ptr += sizeof(*header);
 	if (nr_ctx) {
 		fctx = ptr;
-		fctx->size = ctxlen;
+		fctx->size = lsmctx.len;
 		ptr += sizeof(*fctx);
 
 		strcpy(ptr, name);
 		ptr += namelen;
 
-		memcpy(ptr, ctx, ctxlen);
+		memcpy(ptr, lsmctx.context, lsmctx.len);
 	}
 	ext->size = total_len;
 	ext->value = header;
 	err = 0;
 out_err:
-	kfree(ctx);
+	if (nr_ctx)
+		security_release_secctx(&lsmctx);
 	return err;
 }
 
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 492cffd9d3d8..1813ad9e9320 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -809,7 +809,7 @@  static int nfs_readdir_entry_decode(struct nfs_readdir_descriptor *desc,
 	int ret;
 
 	if (entry->fattr->label)
-		entry->fattr->label->len = NFS4_MAXLABELLEN;
+		entry->fattr->label->lsmctx.len = NFS4_MAXLABELLEN;
 	ret = xdr_decode(desc, entry, stream);
 	if (ret || !desc->plus)
 		return ret;
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 542c7d97b235..d00a6304133a 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -358,14 +358,15 @@  void nfs_setsecurity(struct inode *inode, struct nfs_fattr *fattr)
 		return;
 
 	if ((fattr->valid & NFS_ATTR_FATTR_V4_SECURITY_LABEL) && inode->i_security) {
-		error = security_inode_notifysecctx(inode, fattr->label->label,
-				fattr->label->len);
+		error = security_inode_notifysecctx(inode,
+						fattr->label->lsmctx.context,
+						fattr->label->lsmctx.len);
 		if (error)
 			printk(KERN_ERR "%s() %s %d "
 					"security_inode_notifysecctx() %d\n",
 					__func__,
-					(char *)fattr->label->label,
-					fattr->label->len, error);
+					(char *)fattr->label->lsmctx.context,
+					fattr->label->lsmctx.len, error);
 		nfs_clear_label_invalid(inode);
 	}
 }
@@ -381,12 +382,14 @@  struct nfs4_label *nfs4_label_alloc(struct nfs_server *server, gfp_t flags)
 	if (label == NULL)
 		return ERR_PTR(-ENOMEM);
 
-	label->label = kzalloc(NFS4_MAXLABELLEN, flags);
-	if (label->label == NULL) {
+	label->lsmctx.context = kzalloc(NFS4_MAXLABELLEN, flags);
+	if (label->lsmctx.context == NULL) {
 		kfree(label);
 		return ERR_PTR(-ENOMEM);
 	}
-	label->len = NFS4_MAXLABELLEN;
+	label->lsmctx.len = NFS4_MAXLABELLEN;
+	/* Use an invalid LSM ID as this should never be "released". */
+	label->lsmctx.id = LSM_ID_UNDEF;
 
 	return label;
 }
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 430733e3eff2..96477a57f65a 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -355,13 +355,15 @@  nfs4_label_copy(struct nfs4_label *dst, struct nfs4_label *src)
 	if (!dst || !src)
 		return NULL;
 
-	if (src->len > NFS4_MAXLABELLEN)
+	if (src->lsmctx.len > NFS4_MAXLABELLEN)
 		return NULL;
 
 	dst->lfs = src->lfs;
 	dst->pi = src->pi;
-	dst->len = src->len;
-	memcpy(dst->label, src->label, src->len);
+	/* Use an invalid LSM ID as lsmctx should never be "released" */
+	dst->lsmctx.id = LSM_ID_UNDEF;
+	dst->lsmctx.len = src->lsmctx.len;
+	memcpy(dst->lsmctx.context, src->lsmctx.context, src->lsmctx.len);
 
 	return dst;
 }
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 76776d716744..b07d01f390dc 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -124,12 +124,11 @@  nfs4_label_init_security(struct inode *dir, struct dentry *dentry,
 
 	label->lfs = 0;
 	label->pi = 0;
-	label->len = 0;
-	label->label = NULL;
+	label->lsmctx.len = 0;
+	label->lsmctx.context = NULL;
 
 	err = security_dentry_init_security(dentry, sattr->ia_mode,
-				&dentry->d_name, NULL,
-				(void **)&label->label, &label->len);
+				&dentry->d_name, NULL, &label->lsmctx);
 	if (err == 0)
 		return label;
 
@@ -138,12 +137,8 @@  nfs4_label_init_security(struct inode *dir, struct dentry *dentry,
 static inline void
 nfs4_label_release_security(struct nfs4_label *label)
 {
-	struct lsm_context scaff; /* scaffolding */
-
-	if (label) {
-		lsmcontext_init(&scaff, label->label, label->len, 0);
-		security_release_secctx(&scaff);
-	}
+	if (label)
+		security_release_secctx(&label->lsmctx);
 }
 static inline u32 *nfs4_bitmask(struct nfs_server *server, struct nfs4_label *label)
 {
@@ -6259,7 +6254,7 @@  static int _nfs4_get_security_label(struct inode *inode, void *buf,
 					size_t buflen)
 {
 	struct nfs_server *server = NFS_SERVER(inode);
-	struct nfs4_label label = {0, 0, buflen, buf};
+	struct nfs4_label label = {0, 0, {buf, buflen, -1} };
 
 	u32 bitmask[3] = { 0, 0, FATTR4_WORD2_SECURITY_LABEL };
 	struct nfs_fattr fattr = {
@@ -6287,7 +6282,7 @@  static int _nfs4_get_security_label(struct inode *inode, void *buf,
 		return ret;
 	if (!(fattr.valid & NFS_ATTR_FATTR_V4_SECURITY_LABEL))
 		return -ENOENT;
-	return label.len;
+	return label.lsmctx.len;
 }
 
 static int nfs4_get_security_label(struct inode *inode, void *buf,
@@ -6364,7 +6359,8 @@  static int nfs4_do_set_security_label(struct inode *inode,
 static int
 nfs4_set_security_label(struct inode *inode, const void *buf, size_t buflen)
 {
-	struct nfs4_label ilabel = {0, 0, buflen, (char *)buf };
+	struct nfs4_label ilabel = {0, 0,
+				    {(char *)buf, buflen, -1}};
 	struct nfs_fattr *fattr;
 	int status;
 
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index e8ac3f615f93..61a2b0e61c66 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -1154,7 +1154,7 @@  static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
 	}
 
 	if (label && (attrmask[2] & FATTR4_WORD2_SECURITY_LABEL)) {
-		len += 4 + 4 + 4 + (XDR_QUADLEN(label->len) << 2);
+		len += 4 + 4 + 4 + (XDR_QUADLEN(label->lsmctx.len) << 2);
 		bmval[2] |= FATTR4_WORD2_SECURITY_LABEL;
 	}
 
@@ -1186,8 +1186,9 @@  static void encode_attrs(struct xdr_stream *xdr, const struct iattr *iap,
 	if (label && (bmval[2] & FATTR4_WORD2_SECURITY_LABEL)) {
 		*p++ = cpu_to_be32(label->lfs);
 		*p++ = cpu_to_be32(label->pi);
-		*p++ = cpu_to_be32(label->len);
-		p = xdr_encode_opaque_fixed(p, label->label, label->len);
+		*p++ = cpu_to_be32(label->lsmctx.len);
+		p = xdr_encode_opaque_fixed(p, label->lsmctx.context,
+					    label->lsmctx.len);
 	}
 	if (bmval[2] & FATTR4_WORD2_MODE_UMASK) {
 		*p++ = cpu_to_be32(iap->ia_mode & S_IALLUGO);
@@ -4272,11 +4273,11 @@  static int decode_attr_security_label(struct xdr_stream *xdr, uint32_t *bitmap,
 			return -EIO;
 		bitmap[2] &= ~FATTR4_WORD2_SECURITY_LABEL;
 		if (len < NFS4_MAXLABELLEN) {
-			if (label && label->len) {
-				if (label->len < len)
+			if (label && label->lsmctx.len) {
+				if (label->lsmctx.len < len)
 					return -ERANGE;
-				memcpy(label->label, p, len);
-				label->len = len;
+				memcpy(label->lsmctx.context, p, len);
+				label->lsmctx.len = len;
 				label->pi = pi;
 				label->lfs = lfs;
 				status = NFS_ATTR_FATTR_V4_SECURITY_LABEL;
@@ -4284,10 +4285,11 @@  static int decode_attr_security_label(struct xdr_stream *xdr, uint32_t *bitmap,
 		} else
 			printk(KERN_WARNING "%s: label too long (%u)!\n",
 					__func__, len);
-		if (label && label->label)
+		if (label && label->lsmctx.context)
 			dprintk("%s: label=%.*s, len=%d, PI=%d, LFS=%d\n",
-				__func__, label->len, (char *)label->label,
-				label->len, label->pi, label->lfs);
+				__func__, label->lsmctx.len,
+				(char *)label->lsmctx.context,
+				label->lsmctx.len, label->pi, label->lfs);
 	}
 	return status;
 }
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 69e1076448c6..e2f1ce37c41e 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -83,7 +83,7 @@  LSM_HOOK(int, 0, move_mount, const struct path *from_path,
 	 const struct path *to_path)
 LSM_HOOK(int, -EOPNOTSUPP, dentry_init_security, struct dentry *dentry,
 	 int mode, const struct qstr *name, const char **xattr_name,
-	 void **ctx, u32 *ctxlen)
+	 struct lsm_context *cp)
 LSM_HOOK(int, 0, dentry_create_files_as, struct dentry *dentry, int mode,
 	 struct qstr *name, const struct cred *old, struct cred *new)
 
diff --git a/include/linux/nfs4.h b/include/linux/nfs4.h
index 8d7430d9f218..22032b0f6022 100644
--- a/include/linux/nfs4.h
+++ b/include/linux/nfs4.h
@@ -15,6 +15,7 @@ 
 
 #include <linux/list.h>
 #include <linux/uidgid.h>
+#include <linux/security.h>
 #include <uapi/linux/nfs4.h>
 #include <linux/sunrpc/msg_prot.h>
 
@@ -44,10 +45,9 @@  struct nfs4_acl {
 #define NFS4_MAXLABELLEN	2048
 
 struct nfs4_label {
-	uint32_t	lfs;
-	uint32_t	pi;
-	u32		len;
-	char	*label;
+	uint32_t		lfs;
+	uint32_t		pi;
+	struct lsm_context	lsmctx;
 };
 
 typedef struct { char data[NFS4_VERIFIER_SIZE]; } nfs4_verifier;
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 039898d70954..47652d217d05 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -457,7 +457,7 @@  static inline void nfs4_label_free(struct nfs4_label *label)
 {
 #ifdef CONFIG_NFS_V4_SECURITY_LABEL
 	if (label) {
-		kfree(label->label);
+		kfree(label->lsmctx.context);
 		kfree(label);
 	}
 #endif
diff --git a/include/linux/security.h b/include/linux/security.h
index 7d0adc1833ab..3ad59666e56c 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -237,25 +237,6 @@  struct lsm_context {
 	int	id;		/* Identifies the module */
 };
 
-/**
- * lsmcontext_init - initialize an lsmcontext structure.
- * @cp: Pointer to the context to initialize
- * @context: Initial context, or NULL
- * @size: Size of context, or 0
- * @id: Which LSM provided the context
- *
- * Fill in the lsmcontext from the provided information.
- * This is a scaffolding function that will be removed when
- * lsm_context integration is complete.
- */
-static inline void lsmcontext_init(struct lsm_context *cp, char *context,
-				   u32 size, int id)
-{
-	cp->id = id;
-	cp->context = context;
-	cp->len = size;
-}
-
 /*
  * Values used in the task_security_ops calls
  */
@@ -409,8 +390,8 @@  int security_sb_clone_mnt_opts(const struct super_block *oldsb,
 int security_move_mount(const struct path *from_path, const struct path *to_path);
 int security_dentry_init_security(struct dentry *dentry, int mode,
 				  const struct qstr *name,
-				  const char **xattr_name, void **ctx,
-				  u32 *ctxlen);
+				  const char **xattr_name,
+				  struct lsm_context *lsmcxt);
 int security_dentry_create_files_as(struct dentry *dentry, int mode,
 					struct qstr *name,
 					const struct cred *old,
@@ -883,8 +864,7 @@  static inline int security_dentry_init_security(struct dentry *dentry,
 						 int mode,
 						 const struct qstr *name,
 						 const char **xattr_name,
-						 void **ctx,
-						 u32 *ctxlen)
+						 struct lsm_context *lsmcxt)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/security/security.c b/security/security.c
index 4ca3c9e28b6f..1d57e4e1bceb 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1734,8 +1734,7 @@  void security_inode_free(struct inode *inode)
  * @mode: mode used to determine resource type
  * @name: name of the last path component
  * @xattr_name: name of the security/LSM xattr
- * @ctx: pointer to the resulting LSM context
- * @ctxlen: length of @ctx
+ * @lsmctx: pointer to the resulting LSM context
  *
  * Compute a context for a dentry as the inode is not yet available since NFSv4
  * has no label backed by an EA anyway.  It is important to note that
@@ -1745,11 +1744,11 @@  void security_inode_free(struct inode *inode)
  */
 int security_dentry_init_security(struct dentry *dentry, int mode,
 				  const struct qstr *name,
-				  const char **xattr_name, void **ctx,
-				  u32 *ctxlen)
+				  const char **xattr_name,
+				  struct lsm_context *lsmctx)
 {
 	return call_int_hook(dentry_init_security, dentry, mode, name,
-			     xattr_name, ctx, ctxlen);
+			     xattr_name, lsmctx);
 }
 EXPORT_SYMBOL(security_dentry_init_security);
 
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index ce5e45abd8d3..79776a5e651d 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2869,8 +2869,8 @@  static void selinux_inode_free_security(struct inode *inode)
 
 static int selinux_dentry_init_security(struct dentry *dentry, int mode,
 					const struct qstr *name,
-					const char **xattr_name, void **ctx,
-					u32 *ctxlen)
+					const char **xattr_name,
+					struct lsm_context *cp)
 {
 	u32 newsid;
 	int rc;
@@ -2885,8 +2885,9 @@  static int selinux_dentry_init_security(struct dentry *dentry, int mode,
 	if (xattr_name)
 		*xattr_name = XATTR_NAME_SELINUX;
 
-	return security_sid_to_context(newsid, (char **)ctx,
-				       ctxlen);
+	cp->id = LSM_ID_SELINUX;
+	return security_sid_to_context(newsid, (char **)cp->context,
+				       &cp->len);
 }
 
 static int selinux_dentry_create_files_as(struct dentry *dentry, int mode,