[PATCH v0 0/1] ima: Refactor process_buffer_measurement() to make it generic

[PATCH v0 0/1] ima: Refactor process_buffer_measurement() to make it generic

[Lakshmi Ramasubramanian]

This patch makes the function process_buffer_measurement() generic so that
it can be used to measure more than just the KEXEC_CMDLINE. This function
will also be used for measuring keys, blacklisted binaries, etc.

Lakshmi Ramasubramanian (1):
  ima: Refactor process_buffer_measurement() to make it generic

 security/integrity/ima/ima.h      |  3 +++
 security/integrity/ima/ima_main.c | 29 ++++++++++++++---------------
 2 files changed, 17 insertions(+), 15 deletions(-)

-- 
2.17.1

[PATCH v0 1/1] ima: Refactor process_buffer_measurement() to make it generic

[Lakshmi Ramasubramanian]

This patch makes the function process_buffer_measurement() generic so that
it can be used to measure more than just the KEXEC_CMDLINE. This function
will also be used for measuring keys, blacklisted binaries, etc.

Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
---
 security/integrity/ima/ima.h      |  3 +++
 security/integrity/ima/ima_main.c | 29 ++++++++++++++---------------
 2 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 011b91c79351..b6847ee1f47a 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -209,6 +209,9 @@ void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file,
 			   struct evm_ima_xattr_data *xattr_value,
 			   int xattr_len, int pcr,
 			   struct ima_template_desc *template_desc);
+void process_buffer_measurement(const void *buf, int size,
+				const char *eventname, int pcr,
+				struct ima_template_desc *template_desc);
 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 584019728660..3d5ce4fd4dcc 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -610,14 +610,14 @@ 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.
+ * @pcr: pcr to extend the measurement
+ * @template_desc: template description
  *
  * 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, int pcr,
+				struct ima_template_desc *template_desc)
 {
 	int ret = 0;
 	struct ima_template_entry *entry = NULL;
@@ -626,19 +626,11 @@ 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 {
 		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;
-
-	action = ima_get_action(NULL, cred, secid, 0, KEXEC_CMDLINE, &pcr,
-				&template_desc);
-	if (!(action & IMA_MEASURE))
-		return;
 
 	iint.ima_hash = &hash.hdr;
 	iint.ima_hash->algo = ima_hash_algo;
@@ -670,12 +662,19 @@ static void process_buffer_measurement(const void *buf, int size,
  */
 void ima_kexec_cmdline(const void *buf, int size)
 {
+	int pcr = CONFIG_IMA_MEASURE_PCR_IDX;
+	struct ima_template_desc *template_desc = NULL;
+	int action;
 	u32 secid;
 
 	if (buf && size != 0) {
 		security_task_getsecid(current, &secid);
-		process_buffer_measurement(buf, size, "kexec-cmdline",
-					   current_cred(), secid);
+		action = ima_get_action(NULL, current_cred(), secid, 0,
+					KEXEC_CMDLINE, &pcr, &template_desc);
+		if (!(action & IMA_MEASURE))
+			return;
+		process_buffer_measurement(buf, size, "kexec-cmdline", pcr,
+					   template_desc);
 	}
 }
 
-- 
2.17.1

Re: [PATCH v0 1/1] ima: Refactor process_buffer_measurement() to make it generic

[Nayna]

Hi Lakshmi,


On 10/15/2019 06:05 PM, Lakshmi Ramasubramanian wrote:
> This patch makes the function process_buffer_measurement() generic so that
> it can be used to measure more than just the KEXEC_CMDLINE. This function
> will also be used for measuring keys, blacklisted binaries, etc.

I have just now posted the new version with the change so that we do not 
duplicate the code and it handles both the requirements.

Thanks & Regards,
     - Nayna