[PATCH 01/11] evm: Execute evm_inode_init_security() only when the HMAC key is loaded
From: Roberto Sassu <roberto.sassu@huawei.com>
Date: 2020-06-18 16:04:17
Also in:
linux-security-module, lkml, stable
Subsystem:
extended verification module (evm), integrity measurement architecture (ima), security subsystem, the rest · Maintainers:
Mimi Zohar, Roberto Sassu, Dmitry Kasatkin, Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds
evm_inode_init_security() requires the HMAC key to calculate the HMAC on
initial xattrs provided by LSMs. Unfortunately, with the evm_key_loaded()
check, the function continues even if the HMAC key is not loaded
(evm_key_loaded() returns true also if EVM has been initialized only with a
public key). If the HMAC key is not loaded, evm_inode_init_security()
returns an error later when it calls evm_init_hmac().
Thus, this patch replaces the evm_key_loaded() check with a check of the
EVM_INIT_HMAC flag in evm_initialized, so that evm_inode_init_security()
returns 0 instead of an error.
Cc: stable@vger.kernel.org # 4.5.x
Fixes: 26ddabfe96b ("evm: enable EVM when X509 certificate is loaded")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
security/integrity/evm/evm_main.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index 0d36259b690d..744c105b48d1 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c@@ -521,7 +521,8 @@ int evm_inode_init_security(struct inode *inode, struct evm_xattr *xattr_data; int rc; - if (!evm_key_loaded() || !evm_protected_xattr(lsm_xattr->name)) + if (!(evm_initialized & EVM_INIT_HMAC) || + !evm_protected_xattr(lsm_xattr->name)) return 0; xattr_data = kzalloc(sizeof(*xattr_data), GFP_NOFS);
--
2.17.1