evm: prevent passing integrity check if xattr read fails

This patch fixes a bug, where evm_verify_hmac() returns INTEGRITY_PASS
if inode->i_op->getxattr() returns an error in evm_find_protected_xattrs.

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>

diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index fb71f55..4022012 100644 (file)
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -126,14 +126,15 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry,
        rc = vfs_getxattr_alloc(dentry, XATTR_NAME_EVM, (char **)&xattr_data, 0,
                                GFP_NOFS);
        if (rc <= 0) {
-               if (rc == 0)
-                       evm_status = INTEGRITY_FAIL; /* empty */
-               else if (rc == -ENODATA) {
+               evm_status = INTEGRITY_FAIL;
+               if (rc == -ENODATA) {
                        rc = evm_find_protected_xattrs(dentry);
                        if (rc > 0)
                                evm_status = INTEGRITY_NOLABEL;
                        else if (rc == 0)
                                evm_status = INTEGRITY_NOXATTRS; /* new file */
+               } else if (rc == -EOPNOTSUPP) {
+                       evm_status = INTEGRITY_UNKNOWN;
                }
                goto out;
        }