security: add inode_init_security_anon() LSM hook

This change adds a new LSM hook, inode_init_security_anon(), that will
be used while creating secure anonymous inodes. The hook allows/denies
its creation and assigns a security context to the inode.

The new hook accepts an optional context_inode parameter that callers
can use to provide additional contextual information to security modules
for granting/denying permission to create an anon-inode of the same type.
This context_inode's security_context can also be used to initialize the
newly created anon-inode's security_context.

Signed-off-by: Lokesh Gidra <lokeshgidra@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/security.h b/include/linux/security.h
index c35ea0ffccd9..b0d14f04b16d 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -324,6 +324,9 @@ void security_inode_free(struct inode *inode);
 int security_inode_init_security(struct inode *inode, struct inode *dir,
 				 const struct qstr *qstr,
 				 initxattrs initxattrs, void *fs_data);
+int security_inode_init_security_anon(struct inode *inode,
+				      const struct qstr *name,
+				      const struct inode *context_inode);
 int security_old_inode_init_security(struct inode *inode, struct inode *dir,
 				     const struct qstr *qstr, const char **name,
 				     void **value, size_t *len);
@@ -738,6 +741,13 @@ static inline int security_inode_init_security(struct inode *inode,
 	return 0;
 }
 
+static inline int security_inode_init_security_anon(struct inode *inode,
+						    const struct qstr *name,
+						    const struct inode *context_inode)
+{
+	return 0;
+}
+
 static inline int security_old_inode_init_security(struct inode *inode,
 						   struct inode *dir,
 						   const struct qstr *qstr,