[PATCH v2 1/2] integrity: Add result field in audit message

[PATCH v2 1/2] integrity: Add result field in audit message

[Lakshmi Ramasubramanian]

Result code is not included in the audit messages logged by
the integrity subsystem. Add "result" field in the audit messages
logged by the integrity subsystem and set the value to the result code
passed to integrity_audit_msg() in the "result" parameter.

Sample audit message:

[    6.284329] audit: type=1804 audit(1591756723.627:2): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=kernel op=add_boot_aggregate cause=alloc_entry comm="swapper/0" name="boot_aggregate" res=0 result=-12

[    8.085456] audit: type=1802 audit(1592005947.297:9): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 op=policy_update cause=completed comm="systemd" res=1 result=0

Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Suggested-by: Steve Grubb <sgrubb@redhat.com>
---
 security/integrity/integrity_audit.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/security/integrity/integrity_audit.c b/security/integrity/integrity_audit.c
index 5109173839cc..84002d3d5a95 100644
--- a/security/integrity/integrity_audit.c
+++ b/security/integrity/integrity_audit.c
@@ -53,6 +53,6 @@ void integrity_audit_msg(int audit_msgno, struct inode *inode,
 		audit_log_untrustedstring(ab, inode->i_sb->s_id);
 		audit_log_format(ab, " ino=%lu", inode->i_ino);
 	}
-	audit_log_format(ab, " res=%d", !result);
+	audit_log_format(ab, " res=%d result=%d", !result, result);
 	audit_log_end(ab);
 }
-- 
2.27.0

[PATCH v2 2/2] IMA: Add audit log for failure conditions

[Lakshmi Ramasubramanian]

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:

[    6.415374] audit: type=1804 audit(1592005945.627:2): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=kernel op=measuring_kexec_cmdline cause=alloc_entry comm="swapper/0" name="kexec-cmdline" res=0 result=-12

[    8.085456] audit: type=1802 audit(1592005947.297:9): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 op=policy_update cause=completed comm="systemd" res=1 result=0

[    8.128004] audit: type=1804 audit(1592005947.341:11): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 op=measuring_key cause=hashing_error comm="systemd" name=".builtin_trusted_keys" res=0 result=-22

Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
---
 security/integrity/ima/ima.h            | 48 ++++++++++++++++---------
 security/integrity/ima/ima_main.c       | 18 +++++++---
 security/integrity/ima/ima_policy.c     |  2 +-
 security/integrity/ima/ima_queue_keys.c |  5 +++
 4 files changed, 51 insertions(+), 22 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index df93ac258e01..c3a32e181b48 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -186,27 +186,43 @@ static inline unsigned int ima_hash_key(u8 *digest)
 	return (digest[0] | digest[1] << 8) % IMA_MEASURE_HTABLE_SIZE;
 }
 
-#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,
+#define __ima_hooks(hook)				\
+	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;
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index c1583d98c5e5..8a001aa8e592 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -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_msg(AUDIT_INTEGRITY_PCR, NULL, eventname,
+				    func_measure_str(func),
+				    audit_cause, ret, 0);
 
 	return;
 }
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index e493063a3c34..66aa3e17a888 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -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)
diff --git a/security/integrity/ima/ima_queue_keys.c b/security/integrity/ima/ima_queue_keys.c
index cb3e3f501593..631fd7ab2dcd 100644
--- a/security/integrity/ima/ima_queue_keys.c
+++ b/security/integrity/ima/ima_queue_keys.c
@@ -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_msg(AUDIT_INTEGRITY_PCR, NULL,
+				    keyring->description,
+				    func_measure_str(KEY_CHECK),
+				    audit_cause, rc, 0);
 		ima_free_key_entry(entry);
 		entry = NULL;
 	}
-- 
2.27.0

Re: [PATCH v2 1/2] integrity: Add result field in audit message

[Paul Moore]

On Fri, Jun 12, 2020 at 10:26 PM Lakshmi Ramasubramanian
<nramas@linux.microsoft.com> wrote:
> Result code is not included in the audit messages logged by
> the integrity subsystem. Add "result" field in the audit messages
> logged by the integrity subsystem and set the value to the result code
> passed to integrity_audit_msg() in the "result" parameter.
>
> Sample audit message:
>
> [    6.284329] audit: type=1804 audit(1591756723.627:2): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=kernel op=add_boot_aggregate cause=alloc_entry comm="swapper/0" name="boot_aggregate" res=0 result=-12
>
> [    8.085456] audit: type=1802 audit(1592005947.297:9): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 op=policy_update cause=completed comm="systemd" res=1 result=0
>
> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
> Suggested-by: Steve Grubb <sgrubb@redhat.com>
> ---
>  security/integrity/integrity_audit.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

If we can't use "res=" to carry more than 0/1 then this seems reasonable.

Acked-by: Paul Moore <paul@paul-moore.com>

> diff --git a/security/integrity/integrity_audit.c b/security/integrity/integrity_audit.c
> index 5109173839cc..84002d3d5a95 100644
> --- a/security/integrity/integrity_audit.c
> +++ b/security/integrity/integrity_audit.c
> @@ -53,6 +53,6 @@ void integrity_audit_msg(int audit_msgno, struct inode *inode,
>                 audit_log_untrustedstring(ab, inode->i_sb->s_id);
>                 audit_log_format(ab, " ino=%lu", inode->i_ino);
>         }
> -       audit_log_format(ab, " res=%d", !result);
> +       audit_log_format(ab, " res=%d result=%d", !result, result);
>         audit_log_end(ab);
>  }
> --
> 2.27.0

-- 
paul moore
www.paul-moore.com

Re: [PATCH v2 1/2] integrity: Add result field in audit message

[Steve Grubb]

On Monday, June 15, 2020 6:51:22 PM EDT Paul Moore wrote:
> On Fri, Jun 12, 2020 at 10:26 PM Lakshmi Ramasubramanian
> 
> <nramas@linux.microsoft.com> wrote:
> > Result code is not included in the audit messages logged by
> > the integrity subsystem. Add "result" field in the audit messages
> > logged by the integrity subsystem and set the value to the result code
> > passed to integrity_audit_msg() in the "result" parameter.
> > 
> > Sample audit message:
> > 
> > [    6.284329] audit: type=1804 audit(1591756723.627:2): pid=1 uid=0
> > auid=4294967295 ses=4294967295 subj=kernel op=add_boot_aggregate
> > cause=alloc_entry comm="swapper/0" name="boot_aggregate" res=0
> > result=-12
> > 
> > [    8.085456] audit: type=1802 audit(1592005947.297:9): pid=1 uid=0
> > auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0
> > op=policy_update cause=completed comm="systemd" res=1 result=0
> > 
> > Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
> > Suggested-by: Steve Grubb <sgrubb@redhat.com>
> > ---
> > 
> >  security/integrity/integrity_audit.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> If we can't use "res=" to carry more than 0/1 then this seems reasonable.

Paul,

But we can't do this. The field name dictionary says this is used to convey 
success/fail. It is hard coded in the field interpretation table to look for 
0/1 and interpret that. Interpeting this field will now produce an error 
message. And "result" is a searchable field.

As I suggested a few emails back, let's just use errno or something not 
already taken in the dictionary. NACK.

-Steve

> Acked-by: Paul Moore <paul@paul-moore.com>
> 
> > diff --git a/security/integrity/integrity_audit.c
> > b/security/integrity/integrity_audit.c index 5109173839cc..84002d3d5a95
> > 100644
> > --- a/security/integrity/integrity_audit.c
> > +++ b/security/integrity/integrity_audit.c
> > @@ -53,6 +53,6 @@ void integrity_audit_msg(int audit_msgno, struct inode
> > *inode,> 
> >                 audit_log_untrustedstring(ab, inode->i_sb->s_id);
> >                 audit_log_format(ab, " ino=%lu", inode->i_ino);
> >         
> >         }
> > 
> > -       audit_log_format(ab, " res=%d", !result);
> > +       audit_log_format(ab, " res=%d result=%d", !result, result);
> > 
> >         audit_log_end(ab);
> >  
> >  }
> > 
> > --
> > 2.27.0