From aa2ead71d9daa1b6645e1d25b1f14a6286b114d0 Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Fri, 14 May 2021 17:27:43 +0200 Subject: [PATCH] evm: Load EVM key in ima_load_x509() to avoid appraisal The public builtin keys do not need to be appraised by IMA as the restriction on the IMA/EVM trusted keyrings ensures that a key can be loaded only if it is signed with a key on the builtin or secondary keyrings. However, when evm_load_x509() is called, appraisal is already enabled and a valid IMA signature must be added to the EVM key to pass verification. Since the restriction is applied on both IMA and EVM trusted keyrings, it is safe to disable appraisal also when the EVM key is loaded. This patch calls evm_load_x509() inside ima_load_x509() if CONFIG_IMA_LOAD_X509 is enabled, which crosses the normal IMA and EVM boundary. Signed-off-by: Roberto Sassu Signed-off-by: Mimi Zohar --- security/integrity/iint.c | 4 +++- security/integrity/ima/ima_init.c | 4 ++++ 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/security/integrity/iint.c b/security/integrity/iint.c index fca8a94..8638976 100644 --- a/security/integrity/iint.c +++ b/security/integrity/iint.c @@ -208,7 +208,9 @@ int integrity_kernel_read(struct file *file, loff_t offset, void __init integrity_load_keys(void) { ima_load_x509(); - evm_load_x509(); + + if (!IS_ENABLED(CONFIG_IMA_LOAD_X509)) + evm_load_x509(); } static int __init integrity_fs_init(void) diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c index 6e87429..5076a7d 100644 --- a/security/integrity/ima/ima_init.c +++ b/security/integrity/ima/ima_init.c @@ -108,6 +108,10 @@ void __init ima_load_x509(void) ima_policy_flag &= ~unset_flags; integrity_load_x509(INTEGRITY_KEYRING_IMA, CONFIG_IMA_X509_PATH); + + /* load also EVM key to avoid appraisal */ + evm_load_x509(); + ima_policy_flag |= unset_flags; } #endif -- 2.7.4