linux-kernel - [PATCH v7 5/8] ima: make process_buffer

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Message-Id: <1570497267-13672-6-git-send-email-nayna@linux.ibm.com>
Date:   Mon,  7 Oct 2019 21:14:24 -0400
From:   Nayna Jain <nayna@...ux.ibm.com>
To:     linuxppc-dev@...abs.org, linux-efi@...r.kernel.org,
        linux-integrity@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Michael Ellerman <mpe@...erman.id.au>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Jeremy Kerr <jk@...abs.org>,
        Matthew Garret <matthew.garret@...ula.com>,
        Mimi Zohar <zohar@...ux.ibm.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Claudio Carvalho <cclaudio@...ux.ibm.com>,
        George Wilson <gcwilson@...ux.ibm.com>,
        Elaine Palmer <erpalmer@...ibm.com>,
        Eric Ricther <erichte@...ux.ibm.com>,
        "Oliver O'Halloran" <oohall@...il.com>,
        Nayna Jain <nayna@...ux.ibm.com>
Subject: [PATCH v7 5/8] ima: make process_buffer_measurement() generic

An additional measurement record is needed to indicate the blacklisted
binary. The record will measure the blacklisted binary hash.

This patch makes the function process_buffer_measurement() generic to be
called by the blacklisting function. It modifies the function to handle
more than just the KEXEC_CMDLINE.

Signed-off-by: Nayna Jain <nayna@...ux.ibm.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 3689081aaf38..ed86c1f70d7f 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, 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 60027c643ecd..77115e884496 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.
+ * @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;
@@ -642,19 +642,11 @@ 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;
@@ -686,12 +678,19 @@ 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);
 	}
 }
 
-- 
2.20.1