Re: [PATCH] xattr: Constify ->name member of "struct xattr".

[Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>]

Eric and Mimi, can this patch go to linux-next.git via linux-security.git ?
----------
>From 3f4e9317d1c689a78ac1e94126c74826dbe9c9e3 Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date: Mon, 24 Jun 2013 21:35:22 +0900
Subject: [PATCH] xattr: Constify ->name member of "struct xattr".

Since everybody sets kstrdup()ed constant string to "struct xattr"->name but
nobody modifies "struct xattr"->name , we can omit kstrdup() and its failure
checking by constifying ->name member of "struct xattr".

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Joel Becker <jlbec@evilplan.org> [ocfs2]
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
---
 fs/ocfs2/xattr.h                    |    2 +-
 include/linux/security.h            |    8 ++++----
 include/linux/xattr.h               |    2 +-
 include/uapi/linux/reiserfs_xattr.h |    2 +-
 security/capability.c               |    2 +-
 security/integrity/evm/evm_main.c   |    2 +-
 security/security.c                 |    8 +++-----
 security/selinux/hooks.c            |   17 ++++++-----------
 security/smack/smack_lsm.c          |    9 +++------
 9 files changed, 21 insertions(+), 31 deletions(-)

diff --git a/fs/ocfs2/xattr.h b/fs/ocfs2/xattr.h
index e5c7f15..19f134e 100644
--- a/fs/ocfs2/xattr.h
+++ b/fs/ocfs2/xattr.h
@@ -32,7 +32,7 @@ enum ocfs2_xattr_type {
 
 struct ocfs2_security_xattr_info {
 	int enable;
-	char *name;
+	const char *name;
 	void *value;
 	size_t value_len;
 };
diff --git a/include/linux/security.h b/include/linux/security.h
index 40560f4..2e64d73 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1466,7 +1466,7 @@ struct security_operations {
 	int (*inode_alloc_security) (struct inode *inode);
 	void (*inode_free_security) (struct inode *inode);
 	int (*inode_init_security) (struct inode *inode, struct inode *dir,
-				    const struct qstr *qstr, char **name,
+				    const struct qstr *qstr, const char **name,
 				    void **value, size_t *len);
 	int (*inode_create) (struct inode *dir,
 			     struct dentry *dentry, umode_t mode);
@@ -1737,7 +1737,7 @@ int security_inode_init_security(struct inode *inode, struct inode *dir,
 				 const struct qstr *qstr,
 				 initxattrs initxattrs, void *fs_data);
 int security_old_inode_init_security(struct inode *inode, struct inode *dir,
-				     const struct qstr *qstr, char **name,
+				     const struct qstr *qstr, const char **name,
 				     void **value, size_t *len);
 int security_inode_create(struct inode *dir, struct dentry *dentry, umode_t mode);
 int security_inode_link(struct dentry *old_dentry, struct inode *dir,
@@ -2048,8 +2048,8 @@ static inline int security_inode_init_security(struct inode *inode,
 static inline int security_old_inode_init_security(struct inode *inode,
 						   struct inode *dir,
 						   const struct qstr *qstr,
-						   char **name, void **value,
-						   size_t *len)
+						   const char **name,
+						   void **value, size_t *len)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/include/linux/xattr.h b/include/linux/xattr.h
index fdbafc6..91b0a68 100644
--- a/include/linux/xattr.h
+++ b/include/linux/xattr.h
@@ -31,7 +31,7 @@ struct xattr_handler {
 };
 
 struct xattr {
-	char *name;
+	const char *name;
 	void *value;
 	size_t value_len;
 };
diff --git a/include/uapi/linux/reiserfs_xattr.h b/include/uapi/linux/reiserfs_xattr.h
index d8ce17c..38fdd64 100644
--- a/include/uapi/linux/reiserfs_xattr.h
+++ b/include/uapi/linux/reiserfs_xattr.h
@@ -16,7 +16,7 @@ struct reiserfs_xattr_header {
 };
 
 struct reiserfs_security_handle {
-	char *name;
+	const char *name;
 	void *value;
 	size_t length;
 };
diff --git a/security/capability.c b/security/capability.c
index 1728d4e..b311ff0 100644
--- a/security/capability.c
+++ b/security/capability.c
@@ -119,7 +119,7 @@ static void cap_inode_free_security(struct inode *inode)
 }
 
 static int cap_inode_init_security(struct inode *inode, struct inode *dir,
-				   const struct qstr *qstr, char **name,
+				   const struct qstr *qstr, const char **name,
 				   void **value, size_t *len)
 {
 	return -EOPNOTSUPP;
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index df0fa45..af9b685 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -418,7 +418,7 @@ int evm_inode_init_security(struct inode *inode,
 
 	evm_xattr->value = xattr_data;
 	evm_xattr->value_len = sizeof(*xattr_data);
-	evm_xattr->name = kstrdup(XATTR_EVM_SUFFIX, GFP_NOFS);
+	evm_xattr->name = XATTR_EVM_SUFFIX;
 	return 0;
 out:
 	kfree(xattr_data);
diff --git a/security/security.c b/security/security.c
index a3dce87..8849691 100644
--- a/security/security.c
+++ b/security/security.c
@@ -335,10 +335,10 @@ int security_inode_init_security(struct inode *inode, struct inode *dir,
 	if (unlikely(IS_PRIVATE(inode)))
 		return 0;
 
-	memset(new_xattrs, 0, sizeof new_xattrs);
 	if (!initxattrs)
 		return security_ops->inode_init_security(inode, dir, qstr,
 							 NULL, NULL, NULL);
+	memset(new_xattrs, 0, sizeof(new_xattrs));
 	lsm_xattr = new_xattrs;
 	ret = security_ops->inode_init_security(inode, dir, qstr,
 						&lsm_xattr->name,
@@ -353,16 +353,14 @@ int security_inode_init_security(struct inode *inode, struct inode *dir,
 		goto out;
 	ret = initxattrs(inode, new_xattrs, fs_data);
 out:
-	for (xattr = new_xattrs; xattr->name != NULL; xattr++) {
-		kfree(xattr->name);
+	for (xattr = new_xattrs; xattr->value != NULL; xattr++)
 		kfree(xattr->value);
-	}
 	return (ret == -EOPNOTSUPP) ? 0 : ret;
 }
 EXPORT_SYMBOL(security_inode_init_security);
 
 int security_old_inode_init_security(struct inode *inode, struct inode *dir,
-				     const struct qstr *qstr, char **name,
+				     const struct qstr *qstr, const char **name,
 				     void **value, size_t *len)
 {
 	if (unlikely(IS_PRIVATE(inode)))
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 5c6f2cd..16b8e51 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2516,7 +2516,8 @@ static void selinux_inode_free_security(struct inode *inode)
 }
 
 static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
-				       const struct qstr *qstr, char **name,
+				       const struct qstr *qstr,
+				       const char **name,
 				       void **value, size_t *len)
 {
 	const struct task_security_struct *tsec = current_security();
@@ -2524,7 +2525,7 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
 	struct superblock_security_struct *sbsec;
 	u32 sid, newsid, clen;
 	int rc;
-	char *namep = NULL, *context;
+	char *context;
 
 	dsec = dir->i_security;
 	sbsec = dir->i_sb->s_security;
@@ -2560,19 +2561,13 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
 	if (!ss_initialized || !(sbsec->flags & SE_SBLABELSUPP))
 		return -EOPNOTSUPP;
 
-	if (name) {
-		namep = kstrdup(XATTR_SELINUX_SUFFIX, GFP_NOFS);
-		if (!namep)
-			return -ENOMEM;
-		*name = namep;
-	}
+	if (name)
+		*name = XATTR_SELINUX_SUFFIX;
 
 	if (value && len) {
 		rc = security_sid_to_context_force(newsid, &context, &clen);
-		if (rc) {
-			kfree(namep);
+		if (rc)
 			return rc;
-		}
 		*value = context;
 		*len = clen;
 	}
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 6a08330..2dfccb7 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -582,7 +582,7 @@ static void smack_inode_free_security(struct inode *inode)
  * Returns 0 if it all works out, -ENOMEM if there's no memory
  */
 static int smack_inode_init_security(struct inode *inode, struct inode *dir,
-				     const struct qstr *qstr, char **name,
+				     const struct qstr *qstr, const char **name,
 				     void **value, size_t *len)
 {
 	struct inode_smack *issp = inode->i_security;
@@ -591,11 +591,8 @@ static int smack_inode_init_security(struct inode *inode, struct inode *dir,
 	char *dsp = smk_of_inode(dir);
 	int may;
 
-	if (name) {
-		*name = kstrdup(XATTR_SMACK_SUFFIX, GFP_NOFS);
-		if (*name == NULL)
-			return -ENOMEM;
-	}
+	if (name)
+		*name = XATTR_SMACK_SUFFIX;
 
 	if (value) {
 		rcu_read_lock();
-- 
1.7.1