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evm: audit integrity metadata failures

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Before modifying an EVM protected extended attribute or any other
metadata included in the HMAC calculation, the existing 'security.evm'
is verified.  This patch adds calls to integrity_audit_msg() to audit
integrity metadata failures.

Reported-by: Sven Vermeulen <sven.vermeulen@siphos.be>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
This commit is contained in:
Mimi Zohar 2013-02-21 09:31:22 -05:00
parent d726d8d719
commit 9b97b6cdd4
1 changed files with 14 additions and 1 deletions
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15
security/integrity/evm/evm_main.c
View file

@ -16,6 +16,7 @@
#include <linux/module.h>
#include <linux/crypto.h>
#include <linux/audit.h>
#include <linux/xattr.h>
#include <linux/integrity.h>
#include <linux/evm.h>
@ -24,6 +25,9 @@
int evm_initialized;
static char *integrity_status_msg[] = {
"pass", "fail", "no_label", "no_xattrs", "unknown"
};
char *evm_hmac = "hmac(sha1)";
char *evm_hash = "sha1";
int evm_hmac_version = CONFIG_EVM_HMAC_VERSION;
@ -262,9 +266,15 @@ static int evm_protect_xattr(struct dentry *dentry, const char *xattr_name,
if ((evm_status == INTEGRITY_PASS) ||
(evm_status == INTEGRITY_NOXATTRS))
return 0;
return -EPERM;
goto out;
}
evm_status = evm_verify_current_integrity(dentry);
out:
if (evm_status != INTEGRITY_PASS)
integrity_audit_msg(AUDIT_INTEGRITY_METADATA, dentry->d_inode,
dentry->d_name.name, "appraise_metadata",
integrity_status_msg[evm_status],
-EPERM, 0);
return evm_status == INTEGRITY_PASS ? 0 : -EPERM;
}
@ -357,6 +367,9 @@ int evm_inode_setattr(struct dentry *dentry, struct iattr *attr)
if ((evm_status == INTEGRITY_PASS) ||
(evm_status == INTEGRITY_NOXATTRS))
return 0;
integrity_audit_msg(AUDIT_INTEGRITY_METADATA, dentry->d_inode,
dentry->d_name.name, "appraise_metadata",
integrity_status_msg[evm_status], -EPERM, 0);
return -EPERM;
}