[PATCH v3 3/4] ima: Do not audit if CONFIG_INTEGRITY

Discussion:

[PATCH v3 3/4] ima: Do not audit if CONFIG_INTEGRITY_AUDIT is not set

Stefan Berger

2018-06-04 20:54:54 UTC

If Integrity is not auditing, IMA shouldn't audit, either.

Signed-off-by: Stefan Berger <***@linux.vnet.ibm.com>
---
security/integrity/ima/Kconfig | 1 +
security/integrity/ima/ima_policy.c | 6 +++++-
security/integrity/integrity.h | 15 +++++++++++++++
3 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
index 6a8f67714c83..94c2151331aa 100644
--- a/security/integrity/ima/Kconfig
+++ b/security/integrity/ima/Kconfig
@@ -12,6 +12,7 @@ config IMA
select TCG_TIS if TCG_TPM && X86
select TCG_CRB if TCG_TPM && ACPI
select TCG_IBMVTPM if TCG_TPM && PPC_PSERIES
+ select INTEGRITY_AUDIT if AUDIT
help
The Trusted Computing Group(TCG) runtime Integrity
Measurement Architecture(IMA) maintains a list of hash
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 3fcf0935468c..bc99713dfe57 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -628,6 +628,9 @@ static int ima_lsm_rule_init(struct ima_rule_entry *entry,
static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
bool (*rule_operator)(kuid_t, kuid_t))
{
+ if (!ab)
+ return;
+
if (rule_operator == &uid_gt)
audit_log_format(ab, "%s>", key);
else if (rule_operator == &uid_lt)
@@ -649,7 +652,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
bool uid_token;
int result = 0;

- ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE);
+ ab = integrity_audit_log_start(NULL, GFP_KERNEL,
+ AUDIT_INTEGRITY_RULE);

entry->uid = INVALID_UID;
entry->fowner = INVALID_UID;
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index 0bb372eed62a..e60473b13a8d 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -15,6 +15,7 @@
#include <linux/integrity.h>
#include <crypto/sha.h>
#include <linux/key.h>
+#include <linux/audit.h>

/* iint action cache flags */
#define IMA_MEASURE 0x00000001
@@ -199,6 +200,13 @@ static inline void evm_load_x509(void)
void integrity_audit_msg(int audit_msgno, struct inode *inode,
const unsigned char *fname, const char *op,
const char *cause, int result, int info);
+
+static inline struct audit_buffer *
+integrity_audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, int type)
+{
+ return audit_log_start(ctx, gfp_mask, type);
+}
+
#else
static inline void integrity_audit_msg(int audit_msgno, struct inode *inode,
const unsigned char *fname,
@@ -206,4 +214,11 @@ static inline void integrity_audit_msg(int audit_msgno, struct inode *inode,
int result, int info)
{
}
+
+static inline struct audit_buffer *
+integrity_audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, int type)
+{
+ return NULL;
+}
+
#endif

--
2.13.6

Stefan Berger

2018-06-04 20:54:52 UTC

Permalink

The parameters passed to this logging function are all provided by
a privileged user and therefore we can call audit_log_string()
rather than audit_log_untrustedstring().

Signed-off-by: Stefan Berger <***@linux.vnet.ibm.com>
Suggested-by: Steve Grubb <***@redhat.com>
Acked-by: Paul Moore <***@paul-moore.com>
---
security/integrity/ima/ima_policy.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 8bbc18eb07eb..1d00db19d167 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -634,7 +634,7 @@ static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
audit_log_format(ab, "%s<", key);
else
audit_log_format(ab, "%s=", key);
- audit_log_untrustedstring(ab, value);
+ audit_log_string(ab, value);
audit_log_format(ab, " ");
}
static void ima_log_string(struct audit_buffer *ab, char *key, char *value)

--
2.13.6

Paul Moore

2018-06-05 00:21:55 UTC

Permalink

On Mon, Jun 4, 2018 at 4:54 PM, Stefan Berger

The AUDIT_INTEGRITY_RULE is used for auditing IMA policy rules and
the IMA "audit" policy action. This patch defines
AUDIT_INTEGRITY_POLICY_RULE to reflect the IMA policy rules.
Since we defined a new message type we can now also pass the
audit_context and get an associated SYSCALL record. This now produces

Aaand now I see you included the current->audit_context pointer I
mentioned in my comments for 3/4 ;)

So basically this should be fine, although I should point out that you
do not need to define a new message type to associate records
together. The fact that we don't associate all connected records is
basically a bug.

Anyway, patches 3/4 and 4/4 look good to me. Considering this is
likely going in during the *next* merge window, I would ask that you
convert from "current->audit_context" to "audit_context()" as soon as
this merge window closes.

Thanks!

type=UNKNOWN[1807] msg=audit(1527888965.738:320): action=audit \
func=MMAP_CHECK mask=MAY_EXEC res=1
type=UNKNOWN[1807] msg=audit(1527888965.738:320): action=audit \
func=FILE_CHECK mask=MAY_READ res=1
type=SYSCALL msg=audit(1527888965.738:320): arch=c000003e syscall=1 \
success=yes exit=17 a0=1 a1=55bcfcca9030 a2=11 a3=7fcc1b55fb38 \
items=0 ppid=1567 pid=1601 auid=0 uid=0 gid=0 euid=0 suid=0 \
fsuid=0 egid=0 sgid=0 fsgid=0 tty=tty2 ses=2 comm="echo" \
exe="/usr/bin/echo" \
subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null)
---
include/uapi/linux/audit.h | 1 +
security/integrity/ima/ima_policy.c | 4 ++--
2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index 65d9293f1fb8..cb358551376b 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -148,6 +148,7 @@
#define AUDIT_INTEGRITY_PCR 1804 /* PCR invalidation msgs */
#define AUDIT_INTEGRITY_RULE 1805 /* policy rule */
#define AUDIT_INTEGRITY_EVM_XATTR 1806 /* New EVM-covered xattr */
+#define AUDIT_INTEGRITY_POLICY_RULE 1807 /* IMA policy rules */
#define AUDIT_KERNEL 2000 /* Asynchronous audit record. NOT A REQUEST. */
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index bc99713dfe57..f7230db217a7 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -652,8 +652,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
bool uid_token;
int result = 0;
- ab = integrity_audit_log_start(NULL, GFP_KERNEL,
- AUDIT_INTEGRITY_RULE);
+ ab = integrity_audit_log_start(current->audit_context, GFP_KERNEL,
+ AUDIT_INTEGRITY_POLICY_RULE);
entry->uid = INVALID_UID;
entry->fowner = INVALID_UID;
--
2.13.6

--
paul moore
www.paul-moore.com

Mimi Zohar

2018-06-05 14:15:05 UTC

Permalink

Hi Paul,

Post by Paul Moore
On Mon, Jun 4, 2018 at 4:54 PM, Stefan Berger

Aaand now I see you included the current->audit_context pointer I
mentioned in my comments for 3/4 ;)
So basically this should be fine, although I should point out that you
do not need to define a new message type to associate records
together. The fact that we don't associate all connected records is
basically a bug.
Anyway, patches 3/4 and 4/4 look good to me. Considering this is
likely going in during the *next* merge window, I would ask that you
convert from "current->audit_context" to "audit_context()" as soon as
this merge window closes.
Thanks!

Thanks, Paul. I'd like to start queueing patches for the next open
window now, instead of scrambling later. Can I add your Ack now, and
remember to make this change when rebasing?

Mimi

Post by Paul Moore

Paul Moore

2018-06-05 22:18:34 UTC

Permalink

Post by Mimi Zohar
Hi Paul,

Post by Paul Moore
On Mon, Jun 4, 2018 at 4:54 PM, Stefan Berger

Aaand now I see you included the current->audit_context pointer I
mentioned in my comments for 3/4 ;)
So basically this should be fine, although I should point out that you
do not need to define a new message type to associate records
together. The fact that we don't associate all connected records is
basically a bug.
Anyway, patches 3/4 and 4/4 look good to me. Considering this is
likely going in during the *next* merge window, I would ask that you
convert from "current->audit_context" to "audit_context()" as soon as
this merge window closes.
Thanks!

Thanks, Paul. I'd like to start queueing patches for the next open
window now, instead of scrambling later. Can I add your Ack now, and
remember to make this change when rebasing?

Sure, go ahead and add my ACK to both 3/4 and 4/4 as long as you
double pinky swear you'll do the audit_context() fix-up during the
merge :)

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

--
paul moore
www.paul-moore.com

Mimi Zohar

2018-06-06 14:52:23 UTC

Permalink

Post by Paul Moore

Post by Mimi Zohar
Hi Paul,

Post by Paul Moore
On Mon, Jun 4, 2018 at 4:54 PM, Stefan Berger

Aaand now I see you included the current->audit_context pointer I
mentioned in my comments for 3/4 ;)
So basically this should be fine, although I should point out that you
do not need to define a new message type to associate records
together. The fact that we don't associate all connected records is
basically a bug.
Anyway, patches 3/4 and 4/4 look good to me. Considering this is
likely going in during the *next* merge window, I would ask that you
convert from "current->audit_context" to "audit_context()" as soon as
this merge window closes.
Thanks!

Thanks, Paul. I'd like to start queueing patches for the next open
window now, instead of scrambling later. Can I add your Ack now, and
remember to make this change when rebasing?

Sure, go ahead and add my ACK to both 3/4 and 4/4 as long as you
double pinky swear you'll do the audit_context() fix-up during the
merge :)

Sure, it will be really hard to miss. The next-integrity-queued
branch has:

Signed-off-by: Stefan Berger <***@linux.vnet.ibm.com>

*** Remember replace current->audit_context with call to audit_context() ***
Acked-by: Paul Moore <***@paul-moore.com>
Signed-off-by: Mimi Zohar <***@linux.vnet.ibm.com>

Paul Moore

2018-06-05 00:16:42 UTC

Permalink

On Mon, Jun 4, 2018 at 4:54 PM, Stefan Berger

Post by Stefan Berger
If Integrity is not auditing, IMA shouldn't audit, either.
---
security/integrity/ima/Kconfig | 1 +
security/integrity/ima/ima_policy.c | 6 +++++-
security/integrity/integrity.h | 15 +++++++++++++++
3 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
index 6a8f67714c83..94c2151331aa 100644
--- a/security/integrity/ima/Kconfig
+++ b/security/integrity/ima/Kconfig
@@ -12,6 +12,7 @@ config IMA
select TCG_TIS if TCG_TPM && X86
select TCG_CRB if TCG_TPM && ACPI
select TCG_IBMVTPM if TCG_TPM && PPC_PSERIES
+ select INTEGRITY_AUDIT if AUDIT
help
The Trusted Computing Group(TCG) runtime Integrity
Measurement Architecture(IMA) maintains a list of hash
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 3fcf0935468c..bc99713dfe57 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -628,6 +628,9 @@ static int ima_lsm_rule_init(struct ima_rule_entry *entry,
static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
bool (*rule_operator)(kuid_t, kuid_t))
{
+ if (!ab)
+ return;
+
if (rule_operator == &uid_gt)
audit_log_format(ab, "%s>", key);
else if (rule_operator == &uid_lt)
@@ -649,7 +652,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
bool uid_token;
int result = 0;
- ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE);
+ ab = integrity_audit_log_start(NULL, GFP_KERNEL,
+ AUDIT_INTEGRITY_RULE);

There was a lot of confusion here, so this is understandable, but you
should pass "audit_context()"[1] as the first parameter instead of
NULL. Other than that this patch looks fine.

[1] In Linus' tree at the moment you would need to use
current->audit_context, but the audit PR heading to Linus during this
merge window will introduce the "audit_context()" function which is
preferable as we may need to change things around a bit in the near
future.

Post by Stefan Berger
entry->uid = INVALID_UID;
entry->fowner = INVALID_UID;
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index 0bb372eed62a..e60473b13a8d 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -15,6 +15,7 @@
#include <linux/integrity.h>
#include <crypto/sha.h>
#include <linux/key.h>
+#include <linux/audit.h>
/* iint action cache flags */
#define IMA_MEASURE 0x00000001
@@ -199,6 +200,13 @@ static inline void evm_load_x509(void)
void integrity_audit_msg(int audit_msgno, struct inode *inode,
const unsigned char *fname, const char *op,
const char *cause, int result, int info);
+
+static inline struct audit_buffer *
+integrity_audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, int type)
+{
+ return audit_log_start(ctx, gfp_mask, type);
+}
+
#else
static inline void integrity_audit_msg(int audit_msgno, struct inode *inode,
const unsigned char *fname,
@@ -206,4 +214,11 @@ static inline void integrity_audit_msg(int audit_msgno, struct inode *inode,
int result, int info)
{
}
+
+static inline struct audit_buffer *
+integrity_audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, int type)
+{
+ return NULL;
+}
+
#endif
--
2.13.6

--
paul moore
www.paul-moore.com

Stefan Berger

2018-06-04 20:54:53 UTC

Permalink

Remove the usage of audit_log_string() and replace it with
audit_log_format().

Signed-off-by: Stefan Berger <***@linux.vnet.ibm.com>
Suggested-by: Steve Grubb <***@redhat.com>
Reviewed-by: Mimi Zohar <***@linux.vnet.ibm.com>
Acked-by: Paul Moore <***@paul-moore.com>
---
security/integrity/ima/ima_policy.c | 3 +--
security/integrity/integrity_audit.c | 6 +-----
2 files changed, 2 insertions(+), 7 deletions(-)

diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 1d00db19d167..3fcf0935468c 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -634,8 +634,7 @@ static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value,
audit_log_format(ab, "%s<", key);
else
audit_log_format(ab, "%s=", key);
- audit_log_string(ab, value);
- audit_log_format(ab, " ");
+ audit_log_format(ab, "%s ", value);
}
static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
{
diff --git a/security/integrity/integrity_audit.c b/security/integrity/integrity_audit.c
index 90987d15b6fe..db30763d5525 100644
--- a/security/integrity/integrity_audit.c
+++ b/security/integrity/integrity_audit.c
@@ -45,11 +45,7 @@ void integrity_audit_msg(int audit_msgno, struct inode *inode,
from_kuid(&init_user_ns, audit_get_loginuid(current)),
audit_get_sessionid(current));
audit_log_task_context(ab);
- audit_log_format(ab, " op=");
- audit_log_string(ab, op);
- audit_log_format(ab, " cause=");
- audit_log_string(ab, cause);
- audit_log_format(ab, " comm=");
+ audit_log_format(ab, " op=%s cause=%s comm=", op, cause);
audit_log_untrustedstring(ab, get_task_comm(name, current));
if (fname) {
audit_log_format(ab, " name=");

--
2.13.6