fs/vfs/security: pass last path component to LSM on inode creation

SELinux would like to implement a new labeling behavior of newly created
inodes.  We currently label new inodes based on the parent and the creating
process.  This new behavior would also take into account the name of the
new object when deciding the new label.  This is not the (supposed) full path,
just the last component of the path.

This is very useful because creating /etc/shadow is different than creating
/etc/passwd but the kernel hooks are unable to differentiate these
operations.  We currently require that userspace realize it is doing some
difficult operation like that and than userspace jumps through SELinux hoops
to get things set up correctly.  This patch does not implement new
behavior, that is obviously contained in a seperate SELinux patch, but it
does pass the needed name down to the correct LSM hook.  If no such name
exists it is fine to pass NULL.

Signed-off-by: Eric Paris <eparis@redhat.com>

4 files changed, 12 insertions, 10 deletions

diff --git a/fs/ext3/ialloc.c b/fs/ext3/ialloc.c
index 9724aef..bfc2dc4 100644
--- a/fs/ext3/ialloc.c
+++ b/fs/ext3/ialloc.c
@@ -404,7 +404,8 @@ static int find_group_other(struct super_block *sb, struct inode *parent)
  * For other inodes, search forward from the parent directory's block
  * group to find a free inode.
  */
-struct inode *ext3_new_inode(handle_t *handle, struct inode * dir, int mode)
+struct inode *ext3_new_inode(handle_t *handle, struct inode * dir,
+			     const struct qstr *qstr, int mode)
 {
 	struct super_block *sb;
 	struct buffer_head *bitmap_bh = NULL;
@@ -589,7 +590,7 @@ got:
 	if (err)
 		goto fail_free_drop;
 
-	err = ext3_init_security(handle,inode, dir);
+	err = ext3_init_security(handle, inode, dir, qstr);
 	if (err)
 		goto fail_free_drop;
 
diff --git a/fs/ext3/namei.c b/fs/ext3/namei.c
index bce9dce..a900033 100644
--- a/fs/ext3/namei.c
+++ b/fs/ext3/namei.c
@@ -1707,7 +1707,7 @@ retry:
 	if (IS_DIRSYNC(dir))
 		handle->h_sync = 1;
 
-	inode = ext3_new_inode (handle, dir, mode);
+	inode = ext3_new_inode (handle, dir, &dentry->d_name, mode);
 	err = PTR_ERR(inode);
 	if (!IS_ERR(inode)) {
 		inode->i_op = &ext3_file_inode_operations;
@@ -1743,7 +1743,7 @@ retry:
 	if (IS_DIRSYNC(dir))
 		handle->h_sync = 1;
 
-	inode = ext3_new_inode (handle, dir, mode);
+	inode = ext3_new_inode (handle, dir, &dentry->d_name, mode);
 	err = PTR_ERR(inode);
 	if (!IS_ERR(inode)) {
 		init_special_inode(inode, inode->i_mode, rdev);
@@ -1781,7 +1781,7 @@ retry:
 	if (IS_DIRSYNC(dir))
 		handle->h_sync = 1;
 
-	inode = ext3_new_inode (handle, dir, S_IFDIR | mode);
+	inode = ext3_new_inode (handle, dir, &dentry->d_name, S_IFDIR | mode);
 	err = PTR_ERR(inode);
 	if (IS_ERR(inode))
 		goto out_stop;
@@ -2195,7 +2195,7 @@ retry:
 	if (IS_DIRSYNC(dir))
 		handle->h_sync = 1;
 
-	inode = ext3_new_inode (handle, dir, S_IFLNK|S_IRWXUGO);
+	inode = ext3_new_inode (handle, dir, &dentry->d_name, S_IFLNK|S_IRWXUGO);
 	err = PTR_ERR(inode);
 	if (IS_ERR(inode))
 		goto out_stop;
diff --git a/fs/ext3/xattr.h b/fs/ext3/xattr.h
index 377fe72..2be4f69 100644
--- a/fs/ext3/xattr.h
+++ b/fs/ext3/xattr.h
@@ -128,10 +128,10 @@ exit_ext3_xattr(void)
 
 #ifdef CONFIG_EXT3_FS_SECURITY
 extern int ext3_init_security(handle_t *handle, struct inode *inode,
-				struct inode *dir);
+			      struct inode *dir, const struct qstr *qstr);
 #else
 static inline int ext3_init_security(handle_t *handle, struct inode *inode,
-				struct inode *dir)
+				     struct inode *dir, const struct qstr *qstr)
 {
 	return 0;
 }
diff --git a/fs/ext3/xattr_security.c b/fs/ext3/xattr_security.c
index 03a99bf..b8d9f83 100644
--- a/fs/ext3/xattr_security.c
+++ b/fs/ext3/xattr_security.c
@@ -49,14 +49,15 @@ ext3_xattr_security_set(struct dentry *dentry, const char *name,
 }
 
 int
-ext3_init_security(handle_t *handle, struct inode *inode, struct inode *dir)
+ext3_init_security(handle_t *handle, struct inode *inode, struct inode *dir,
+		   const struct qstr *qstr)
 {
 	int err;
 	size_t len;
 	void *value;
 	char *name;
 
-	err = security_inode_init_security(inode, dir, &name, &value, &len);
+	err = security_inode_init_security(inode, dir, qstr, &name, &value, &len);
 	if (err) {
 		if (err == -EOPNOTSUPP)
 			return 0;