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>

3 files changed, 11 insertions, 8 deletions

diff --git a/fs/jfs/jfs_xattr.h b/fs/jfs/jfs_xattr.h
index 88b6cc5..e9e100f 100644
--- a/fs/jfs/jfs_xattr.h
+++ b/fs/jfs/jfs_xattr.h
@@ -62,10 +62,11 @@ extern ssize_t jfs_listxattr(struct dentry *, char *, size_t);
 extern int jfs_removexattr(struct dentry *, const char *);
 
 #ifdef CONFIG_JFS_SECURITY
-extern int jfs_init_security(tid_t, struct inode *, struct inode *);
+extern int jfs_init_security(tid_t, struct inode *, struct inode *,
+			     const struct qstr *);
 #else
 static inline int jfs_init_security(tid_t tid, struct inode *inode,
-				    struct inode *dir)
+				    struct inode *dir, const struct qstr *qstr)
 {
 	return 0;
 }
diff --git a/fs/jfs/namei.c b/fs/jfs/namei.c
index 4414e3a..030b917 100644
--- a/fs/jfs/namei.c
+++ b/fs/jfs/namei.c
@@ -115,7 +115,7 @@ static int jfs_create(struct inode *dip, struct dentry *dentry, int mode,
 	if (rc)
 		goto out3;
 
-	rc = jfs_init_security(tid, ip, dip);
+	rc = jfs_init_security(tid, ip, dip, &dentry->d_name);
 	if (rc) {
 		txAbort(tid, 0);
 		goto out3;
@@ -253,7 +253,7 @@ static int jfs_mkdir(struct inode *dip, struct dentry *dentry, int mode)
 	if (rc)
 		goto out3;
 
-	rc = jfs_init_security(tid, ip, dip);
+	rc = jfs_init_security(tid, ip, dip, &dentry->d_name);
 	if (rc) {
 		txAbort(tid, 0);
 		goto out3;
@@ -932,7 +932,7 @@ static int jfs_symlink(struct inode *dip, struct dentry *dentry,
 	mutex_lock_nested(&JFS_IP(dip)->commit_mutex, COMMIT_MUTEX_PARENT);
 	mutex_lock_nested(&JFS_IP(ip)->commit_mutex, COMMIT_MUTEX_CHILD);
 
-	rc = jfs_init_security(tid, ip, dip);
+	rc = jfs_init_security(tid, ip, dip, &dentry->d_name);
 	if (rc)
 		goto out3;
 
@@ -1395,7 +1395,7 @@ static int jfs_mknod(struct inode *dir, struct dentry *dentry,
 	if (rc)
 		goto out3;
 
-	rc = jfs_init_security(tid, ip, dir);
+	rc = jfs_init_security(tid, ip, dir, &dentry->d_name);
 	if (rc) {
 		txAbort(tid, 0);
 		goto out3;
diff --git a/fs/jfs/xattr.c b/fs/jfs/xattr.c
index 2d7f165..3fa4c32 100644
--- a/fs/jfs/xattr.c
+++ b/fs/jfs/xattr.c
@@ -1091,7 +1091,8 @@ int jfs_removexattr(struct dentry *dentry, const char *name)
 }
 
 #ifdef CONFIG_JFS_SECURITY
-int jfs_init_security(tid_t tid, struct inode *inode, struct inode *dir)
+int jfs_init_security(tid_t tid, struct inode *inode, struct inode *dir,
+		      const struct qstr *qstr)
 {
 	int rc;
 	size_t len;
@@ -1099,7 +1100,8 @@ int jfs_init_security(tid_t tid, struct inode *inode, struct inode *dir)
 	char *suffix;
 	char *name;
 
-	rc = security_inode_init_security(inode, dir, &suffix, &value, &len);
+	rc = security_inode_init_security(inode, dir, qstr, &suffix, &value,
+					  &len);
 	if (rc) {
 		if (rc == -EOPNOTSUPP)
 			return 0;