Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

Pull Integrity subsystem fix from James Morris:
 "These changes fix a bug in xattr handling, where the evm and ima
  inode_setxattr() functions do not check for empty xattrs being passed
  from userspace (leading to user-triggerable null pointer
  dereferences)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  evm: check xattr value length and type in evm_inode_setxattr()
  ima: check xattr value length and type in the ima_inode_setxattr()

Author: torvalds

security/integrity/evm/evm_main.c

@@ -319,9 +319,12 @@ int evm_inode_setxattr(struct dentry *dentry, const char *xattr_name,
 {
 	const struct evm_ima_xattr_data *xattr_data = xattr_value;
 
-	if ((strcmp(xattr_name, XATTR_NAME_EVM) == 0)
-	    && (xattr_data->type == EVM_XATTR_HMAC))
-		return -EPERM;
+	if (strcmp(xattr_name, XATTR_NAME_EVM) == 0) {
+		if (!xattr_value_len)
+			return -EINVAL;
+		if (xattr_data->type != EVM_IMA_XATTR_DIGSIG)
+			return -EPERM;
+	}
 	return evm_protect_xattr(dentry, xattr_name, xattr_value,
 				 xattr_value_len);
 }

security/integrity/ima/ima_appraise.c

@@ -378,6 +378,8 @@ int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name,
 	result = ima_protect_xattr(dentry, xattr_name, xattr_value,
 				   xattr_value_len);
 	if (result == 1) {
+		if (!xattr_value_len || (xvalue->type >= IMA_XATTR_LAST))
+			return -EINVAL;
 		ima_reset_appraise_flags(dentry->d_inode,
 			 (xvalue->type == EVM_IMA_XATTR_DIGSIG) ? 1 : 0);
 		result = 0;

security/integrity/integrity.h

@@ -61,6 +61,7 @@ enum evm_ima_xattr_type {
 	EVM_XATTR_HMAC,
 	EVM_IMA_XATTR_DIGSIG,
 	IMA_XATTR_DIGEST_NG,
+	IMA_XATTR_LAST
 };
 
 struct evm_ima_xattr_data {