evm: add evm_inode_setattr to prevent updating an invalid security.evm

Permit changing of security.evm only when valid, unless in fixmode.

Reported-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/security/security.c b/security/security.c
index 181990ae90c1..19251ccb2de0 100644
--- a/security/security.c
+++ b/security/security.c
@@ -571,9 +571,14 @@ int security_inode_exec_permission(struct inode *inode, unsigned int flags)
 
 int security_inode_setattr(struct dentry *dentry, struct iattr *attr)
 {
+        int ret;
+
         if (unlikely(IS_PRIVATE(dentry->d_inode)))
                 return 0;
-        return security_ops->inode_setattr(dentry, attr);
+        ret = security_ops->inode_setattr(dentry, attr);
+        if (ret)
+                return ret;
+        return evm_inode_setattr(dentry, attr);
 }
 EXPORT_SYMBOL_GPL(security_inode_setattr);