@@ -1339,9 +1339,11 @@
has equivalent usage. See its documentation for details.
evm= [EVM]
- Format: { "fix" }
- Permit 'security.evm' to be updated regardless of
- current integrity status.
+ Format: { "fix" | "allow_metadata_writes" | "complete" }
+ fix: permit 'security.evm' to be updated regardless of
+ current integrity status;
+ allow_metadata_writes: permit metadata modificatons;
+ complete: don't allow further changes of the EVM mode.
evm_hash= [EVM] Hash algorithm used to calculate the HMAC.
Format: { md5 | sha1 | rmd160 | sha256 | sha384
@@ -56,17 +56,22 @@ static struct xattr_list evm_config_default_xattrnames[] = {
LIST_HEAD(evm_config_xattrnames);
-static int evm_fixmode;
-static int __init evm_set_fixmode(char *str)
+static int evm_fixmode __ro_after_init;
+static int evm_complete __ro_after_init;
+static int __init evm_set_param(char *str)
{
if (strncmp(str, "fix", 3) == 0)
evm_fixmode = 1;
+ else if (strncmp(str, "allow_metadata_writes", 21) == 0)
+ evm_initialized |= EVM_ALLOW_METADATA_WRITES;
+ else if (strncmp(str, "complete", 8) == 0)
+ evm_complete = 1;
else
pr_err("invalid \"%s\" mode", str);
return 0;
}
-__setup("evm=", evm_set_fixmode);
+__setup("evm=", evm_set_param);
static void __init evm_init_config(void)
{
@@ -737,8 +742,11 @@ void __init evm_load_x509(void)
int rc;
rc = integrity_load_x509(INTEGRITY_KEYRING_EVM, CONFIG_EVM_X509_PATH);
- if (!rc)
+ if (!rc) {
evm_initialized |= EVM_INIT_X509;
+ if (evm_complete)
+ evm_initialized |= EVM_SETUP_COMPLETE;
+ }
}
#endif
With the patch 'evm: Ignore INTEGRITY_NOLABEL/INTEGRITY_NOXATTRS if conditions are safe', the INTEGRITY_NOLABEL and INTEGRITY_NOXATTRS errors can be ignored by setting the EVM_SETUP_COMPLETE flag. Also, the same errors can be avoided by disabling EVM verification completely with the EVM_ALLOW_METADATA_WRITES flag. This patch makes it possible to set these initialization flags directly in the kernel command line, so that no additional setup is required from the initial ram disk. The new allowed values for evm= are: allow_metadata_writes: permit metadata modificatons; complete: don't allow further changes of the EVM mode. While EVM_ALLOW_METADATA_WRITES will be applied directly by the kernel at setup time, EVM_SETUP_COMPLETE will be applied only if a public key is loaded by evm_load_x509(). Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> --- Documentation/admin-guide/kernel-parameters.txt | 8 +++++--- security/integrity/evm/evm_main.c | 16 ++++++++++++---- 2 files changed, 17 insertions(+), 7 deletions(-)