Commit 34e980bb authored by Lakshmi Ramasubramanian's avatar Lakshmi Ramasubramanian Committed by Mimi Zohar
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IMA: Add audit log for failure conditions 



process_buffer_measurement() and ima_alloc_key_entry() functions need to
log an audit message for auditing integrity measurement failures.

Add audit message in these two functions. Remove "pr_devel" log message
in process_buffer_measurement().

Sample audit messages:

[    6.303048] audit: type=1804 audit(1592506281.627:2): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=kernel op=measuring_key cause=ENOMEM comm="swapper/0" name=".builtin_trusted_keys" res=0 errno=-12

[    8.019432] audit: type=1804 audit(1592506283.344:10): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 op=measuring_kexec_cmdline cause=hashing_error comm="systemd" name="kexec-cmdline" res=0 errno=-22

Signed-off-by: default avatarLakshmi Ramasubramanian <nramas@linux.microsoft.com>
Suggested-by: default avatarMimi Zohar <zohar@linux.ibm.com>
Signed-off-by: default avatarMimi Zohar <zohar@linux.ibm.com>
parent 2f845882

security/integrity/ima/ima.h

+32 −16
Original line number Diff line number Diff line
@@ -187,26 +187,42 @@ static inline unsigned int ima_hash_key(u8 *digest) 
}



#define __ima_hooks(hook)				\

	hook(NONE)			\

	hook(FILE_CHECK)		\

	hook(MMAP_CHECK)		\

	hook(BPRM_CHECK)		\

	hook(CREDS_CHECK)		\

	hook(POST_SETATTR)		\

	hook(MODULE_CHECK)		\

	hook(FIRMWARE_CHECK)		\

	hook(KEXEC_KERNEL_CHECK)	\

	hook(KEXEC_INITRAMFS_CHECK)	\

	hook(POLICY_CHECK)		\

	hook(KEXEC_CMDLINE)		\

	hook(KEY_CHECK)			\

	hook(MAX_CHECK)

#define __ima_hook_enumify(ENUM)	ENUM,

	hook(NONE, none)				\

	hook(FILE_CHECK, file)				\

	hook(MMAP_CHECK, mmap)				\

	hook(BPRM_CHECK, bprm)				\

	hook(CREDS_CHECK, creds)			\

	hook(POST_SETATTR, post_setattr)		\

	hook(MODULE_CHECK, module)			\

	hook(FIRMWARE_CHECK, firmware)			\

	hook(KEXEC_KERNEL_CHECK, kexec_kernel)		\

	hook(KEXEC_INITRAMFS_CHECK, kexec_initramfs)	\

	hook(POLICY_CHECK, policy)			\

	hook(KEXEC_CMDLINE, kexec_cmdline)		\

	hook(KEY_CHECK, key)				\

	hook(MAX_CHECK, none)



#define __ima_hook_enumify(ENUM, str)	ENUM,

#define __ima_stringify(arg) (#arg)

#define __ima_hook_measuring_stringify(ENUM, str) \

		(__ima_stringify(measuring_ ##str)),



enum ima_hooks {

	__ima_hooks(__ima_hook_enumify)

};



static const char * const ima_hooks_measure_str[] = {

	__ima_hooks(__ima_hook_measuring_stringify)

};



static inline const char *func_measure_str(enum ima_hooks func)

{

	if (func >= MAX_CHECK)

		return ima_hooks_measure_str[NONE];



	return ima_hooks_measure_str[func];

}



extern const char *const func_tokens[];



struct modsig;

security/integrity/ima/ima_main.c

+13 −5
Original line number Diff line number Diff line
@@ -740,6 +740,7 @@ void process_buffer_measurement(const void *buf, int size, 
				int pcr, const char *keyring)

{

	int ret = 0;

	const char *audit_cause = "ENOMEM";

	struct ima_template_entry *entry = NULL;

	struct integrity_iint_cache iint = {};

	struct ima_event_data event_data = {.iint = &iint,
@@ -794,21 +795,28 @@ void process_buffer_measurement(const void *buf, int size, 
	iint.ima_hash->length = hash_digest_size[ima_hash_algo];



	ret = ima_calc_buffer_hash(buf, size, iint.ima_hash);

	if (ret < 0)

	if (ret < 0) {

		audit_cause = "hashing_error";

		goto out;

	}



	ret = ima_alloc_init_template(&event_data, &entry, template);

	if (ret < 0)

	if (ret < 0) {

		audit_cause = "alloc_entry";

		goto out;

	}



	ret = ima_store_template(entry, violation, NULL, buf, pcr);



	if (ret < 0)

	if (ret < 0) {

		audit_cause = "store_entry";

		ima_free_template_entry(entry);

	}



out:

	if (ret < 0)

		pr_devel("%s: failed, result: %d\n", __func__, ret);

		integrity_audit_message(AUDIT_INTEGRITY_PCR, NULL, eventname,

					func_measure_str(func),

					audit_cause, ret, 0, ret);



	return;

}

security/integrity/ima/ima_policy.c

+1 −1
Original line number Diff line number Diff line
@@ -1414,7 +1414,7 @@ void ima_delete_rules(void) 
	}

}



#define __ima_hook_stringify(str)	(#str),

#define __ima_hook_stringify(func, str)	(#func),



const char *const func_tokens[] = {

	__ima_hooks(__ima_hook_stringify)

security/integrity/ima/ima_queue_keys.c

+5 −0
Original line number Diff line number Diff line
@@ -68,6 +68,7 @@ static struct ima_key_entry *ima_alloc_key_entry(struct key *keyring, 
						 size_t payload_len)

{

	int rc = 0;

	const char *audit_cause = "ENOMEM";

	struct ima_key_entry *entry;



	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
@@ -88,6 +89,10 @@ static struct ima_key_entry *ima_alloc_key_entry(struct key *keyring, 


out:

	if (rc) {

		integrity_audit_message(AUDIT_INTEGRITY_PCR, NULL,

					keyring->description,

					func_measure_str(KEY_CHECK),

					audit_cause, rc, 0, rc);

		ima_free_key_entry(entry);

		entry = NULL;

	}

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