[PATCHv2] use event name instead of enum to make the call generic

From: Prakhar Srivastava <prsriva02@gmail.com>
To: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: zohar@linux.vnet.ibm.com,
	Prakhar Srivastava <prsriva02@gmail.com>,
	Prakhar Srivastava <prsriva@microsoft.com>
Subject: [PATCHv2] use event name instead of enum to make the call generic
Date: Fri, 19 Apr 2019 17:00:56 -0700	[thread overview]
Message-ID: <20190420000057.5222-2-prsriva02@gmail.com> (raw)
In-Reply-To: <20190420000057.5222-1-prsriva02@gmail.com>

From: Prakhar Srivastava <prsriva02@gmail.com>

Signed-off-by: Prakhar Srivastava <prsriva@microsoft.com>
---

remove enaums to control type of buffers entries, instead pass the event name to be used.

 include/linux/ima.h               | 10 ++--------
 kernel/kexec_file.c               |  3 +++
 security/integrity/ima/ima.h      |  2 +-
 security/integrity/ima/ima_main.c | 30 ++++++++++--------------------
 4 files changed, 16 insertions(+), 29 deletions(-)

diff --git a/include/linux/ima.h b/include/linux/ima.h
index 733d0cb9dedc..5e41507c57e5 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -14,12 +14,6 @@
 #include <linux/kexec.h>
 struct linux_binprm;
 
-enum __buffer_id {
-	KERNEL_VERSION,
-	KEXEC_CMDLINE,
-	MAX_BUFFER_ID = KEXEC_CMDLINE
-} buffer_id;
-
 #ifdef CONFIG_IMA
 extern int ima_bprm_check(struct linux_binprm *bprm);
 extern int ima_file_check(struct file *file, int mask, int opened);
@@ -29,7 +23,7 @@ extern int ima_read_file(struct file *file, enum kernel_read_file_id id);
 extern int ima_post_read_file(struct file *file, void *buf, loff_t size,
 			      enum kernel_read_file_id id);
 extern void ima_post_path_mknod(struct dentry *dentry);
-extern void ima_buffer_check(const void *buff, int size, enum buffer_id id);
+extern void ima_buffer_check(const void *buff, int size, char *eventname);
 #ifdef CONFIG_IMA_KEXEC
 extern void ima_add_kexec_buffer(struct kimage *image);
 #endif
@@ -72,7 +66,7 @@ static inline void ima_post_path_mknod(struct dentry *dentry)
 }
 
 static inline void ima_buffer_check(const void *buff, int size,
-			enum buffer_id id)
+			char *eventname)
 {
 	return;
 }
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index b118735fea9d..2a5234eb4b28 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -182,6 +182,9 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
 			ret = -EINVAL;
 			goto out;
 		}
+
+		ima_buffer_check(image->cmdline_buf, cmdline_len - 1,
+				"kexec_cmdline");
 	}
 
 	/* Call arch image load handlers */
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index b71f2f6f7421..fcade3c103ed 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -181,8 +181,8 @@ enum ima_hooks {
 	FIRMWARE_CHECK,
 	KEXEC_KERNEL_CHECK,
 	KEXEC_INITRAMFS_CHECK,
-	BUFFER_CHECK,
 	POLICY_CHECK,
+	BUFFER_CHECK,
 	MAX_CHECK
 };
 
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 6408cadaadbb..da82c705a5ed 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -160,8 +160,7 @@ void ima_file_free(struct file *file)
  * (Instead of using the file hash the buffer hash is used).
  * @buff - The buffer that needs to be added to the log
  * @size - size of buffer(in bytes)
- * @id - buffer id, this is differentiator for the various buffers
- * that can be measured.
+ * @id - eventname, event name to be used for buffer measurement.
  *
  * The buffer passed is added to the ima logs.
  * If the sig template is used, then the sig field contains the buffer.
@@ -170,7 +169,7 @@ void ima_file_free(struct file *file)
  * On error cases surface errors from ima calls.
  */
 static int process_buffer_measurement(const void *buff, int size,
-				enum buffer_id id)
+				char *eventname)
 {
 	int ret = -EINVAL;
 	struct ima_template_entry *entry = NULL;
@@ -185,23 +184,13 @@ static int process_buffer_measurement(const void *buff, int size,
 	int violation = 0;
 	int pcr = CONFIG_IMA_MEASURE_PCR_IDX;
 
-	if (!buff || size ==  0)
+	if (!buff || size ==  0 || !eventname)
 		goto err_out;
 
 	if (ima_get_action(NULL, 0, BUFFER_CHECK, &pcr) != IMA_MEASURE)
 		goto err_out;
 
-	switch (buffer_id) {
-	case KERNEL_VERSION:
-		name = "Kernel-version";
-		break;
-	case KEXEC_CMDLINE:
-		name = "Kexec-cmdline";
-		break;
-	default:
-		goto err_out;
-	}
-
+	name = eventname;
 	memset(iint, 0, sizeof(*iint));
 	memset(&hash, 0, sizeof(hash));
 
@@ -452,15 +441,16 @@ int ima_read_file(struct file *file, enum kernel_read_file_id read_id)
  * ima_buffer_check - based on policy, collect & store buffer measurement
  * @buf: pointer to buffer
  * @size: size of buffer
- * @buffer_id: caller identifier
+ * @eventname: caller identifier
  *
  * Buffers can only be measured, not appraised.  The buffer identifier
- * is used as the measurement list entry name (eg. boot_cmdline).
+ * is used as the measurement list entry name (eg. boot_cmdline,
+ * kernel_version).
  */
-void ima_buffer_check(const void *buf, int size, enum buffer_id id)
+void ima_buffer_check(const void *buf, int size, char *eventname)
 {
-	if (buf && size != 0)
-		process_buffer_measurement(buf, size, id);
+	if (buf && size != 0 && eventname)
+		process_buffer_measurement(buf, size, eventname);
 
 	return;
 }
-- 
2.17.1

