[v8,5/8] ima: make process_buffer_measurement() generic
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Message ID 1571508377-23603-6-git-send-email-nayna@linux.ibm.com
State Superseded
Headers show
Series
  • powerpc: Enabling IMA arch specific secure boot policies
Related show

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Context Check Description
snowpatch_ozlabs/checkpatch warning total: 0 errors, 0 warnings, 2 checks, 95 lines checked
snowpatch_ozlabs/apply_patch success Successfully applied on branch next (600802af9049be799465b24d14162918545634bf)

Commit Message

Nayna Jain Oct. 19, 2019, 6:06 p.m. UTC
process_buffer_measurement() is limited to measuring the kexec boot
command line. This patch makes process_buffer_measurement() more
generic, allowing it to measure other types of buffer data (e.g.
blacklisted binary hashes or key hashes).

This patch modifies the function to conditionally retrieve the policy
defined pcr and template based on the func.

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
---
 security/integrity/ima/ima.h      |  3 ++
 security/integrity/ima/ima_main.c | 51 ++++++++++++++++++++-----------
 2 files changed, 36 insertions(+), 18 deletions(-)

Comments

Mimi Zohar Oct. 20, 2019, 1:21 a.m. UTC | #1
On Sat, 2019-10-19 at 14:06 -0400, Nayna Jain wrote:
> process_buffer_measurement() is limited to measuring the kexec boot
> command line. This patch makes process_buffer_measurement() more
> generic, allowing it to measure other types of buffer data (e.g.
> blacklisted binary hashes or key hashes).

based on "func".
> 
> This patch modifies the function to conditionally retrieve the policy
> defined pcr and template based on the func.

This would be done in a subsequent patch, not here.

> @@ -642,19 +642,38 @@ static void process_buffer_measurement(const void *buf, int size,
>  					    .filename = eventname,
>  					    .buf = buf,
>  					    .buf_len = size};
> -	struct ima_template_desc *template_desc = NULL;
> +	struct ima_template_desc *template = NULL;
>  	struct {
>  		struct ima_digest_data hdr;
>  		char digest[IMA_MAX_DIGEST_SIZE];
>  	} hash = {};
>  	int violation = 0;
> -	int pcr = CONFIG_IMA_MEASURE_PCR_IDX;
>  	int action = 0;
> +	u32 secid;
>  
> -	action = ima_get_action(NULL, cred, secid, 0, KEXEC_CMDLINE, &pcr,
> -				&template_desc);
> -	if (!(action & IMA_MEASURE))
> -		return;
> +	if (func) {
> +		security_task_getsecid(current, &secid);
> +		action = ima_get_action(NULL, current_cred(), secid, 0, func,
> +					&pcr, &template);
> +		if (!(action & IMA_MEASURE))
> +			return;
> +	}
> +

Initially there is no need to test "func".  A specific "func" test
would be added as needed. 

Mimi

Patch
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diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 3689081aaf38..a65772ffa427 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -217,6 +217,9 @@  void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file,
 			   struct evm_ima_xattr_data *xattr_value,
 			   int xattr_len, const struct modsig *modsig, int pcr,
 			   struct ima_template_desc *template_desc);
+void process_buffer_measurement(const void *buf, int size,
+				const char *eventname, enum ima_hooks func,
+				int pcr);
 void ima_audit_measurement(struct integrity_iint_cache *iint,
 			   const unsigned char *filename);
 int ima_alloc_init_template(struct ima_event_data *event_data,
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 60027c643ecd..fe0b704ffdeb 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -626,14 +626,14 @@  int ima_load_data(enum kernel_load_data_id id)
  * @buf: pointer to the buffer that needs to be added to the log.
  * @size: size of buffer(in bytes).
  * @eventname: event name to be used for the buffer entry.
- * @cred: a pointer to a credentials structure for user validation.
- * @secid: the secid of the task to be validated.
+ * @func: IMA hook
+ * @pcr: pcr to extend the measurement
  *
  * Based on policy, the buffer is measured into the ima log.
  */
-static void process_buffer_measurement(const void *buf, int size,
-				       const char *eventname,
-				       const struct cred *cred, u32 secid)
+void process_buffer_measurement(const void *buf, int size,
+				const char *eventname, enum ima_hooks func,
+				int pcr)
 {
 	int ret = 0;
 	struct ima_template_entry *entry = NULL;
@@ -642,19 +642,38 @@  static void process_buffer_measurement(const void *buf, int size,
 					    .filename = eventname,
 					    .buf = buf,
 					    .buf_len = size};
-	struct ima_template_desc *template_desc = NULL;
+	struct ima_template_desc *template = NULL;
 	struct {
 		struct ima_digest_data hdr;
 		char digest[IMA_MAX_DIGEST_SIZE];
 	} hash = {};
 	int violation = 0;
-	int pcr = CONFIG_IMA_MEASURE_PCR_IDX;
 	int action = 0;
+	u32 secid;
 
-	action = ima_get_action(NULL, cred, secid, 0, KEXEC_CMDLINE, &pcr,
-				&template_desc);
-	if (!(action & IMA_MEASURE))
-		return;
+	if (func) {
+		security_task_getsecid(current, &secid);
+		action = ima_get_action(NULL, current_cred(), secid, 0, func,
+					&pcr, &template);
+		if (!(action & IMA_MEASURE))
+			return;
+	}
+
+	if (!pcr)
+		pcr = CONFIG_IMA_MEASURE_PCR_IDX;
+
+	if (!template) {
+		template = lookup_template_desc("ima-buf");
+		ret = template_desc_init_fields(template->fmt,
+						&(template->fields),
+						&(template->num_fields));
+		if (ret < 0) {
+			pr_err("template %s init failed, result: %d\n",
+			       (strlen(template->name) ?
+				template->name : template->fmt), ret);
+			return;
+		}
+	}
 
 	iint.ima_hash = &hash.hdr;
 	iint.ima_hash->algo = ima_hash_algo;
@@ -664,7 +683,7 @@  static void process_buffer_measurement(const void *buf, int size,
 	if (ret < 0)
 		goto out;
 
-	ret = ima_alloc_init_template(&event_data, &entry, template_desc);
+	ret = ima_alloc_init_template(&event_data, &entry, template);
 	if (ret < 0)
 		goto out;
 
@@ -686,13 +705,9 @@  static void process_buffer_measurement(const void *buf, int size,
  */
 void ima_kexec_cmdline(const void *buf, int size)
 {
-	u32 secid;
-
-	if (buf && size != 0) {
-		security_task_getsecid(current, &secid);
+	if (buf && size != 0)
 		process_buffer_measurement(buf, size, "kexec-cmdline",
-					   current_cred(), secid);
-	}
+					   KEXEC_CMDLINE, 0);
 }
 
 static int __init init_ima(void)