[PATCH v10 1/8] ima: rename variable the ser_file "file" to "ima_kexec_file"

[steven chen <chenste@linux.microsoft.com>]

The name of the local variable "file" of type seq_file defined in the
ima_dump_measurement_list function is too generic. To better reflect the
purpose of the variable, rename it to "ima_kexec_file". This change will 
help improve code readability and maintainability by making the variable's
role more explicit.

The variable ima_kexec_file is indeed the memory allocated for copying IMA
measurement records. The ima_dump_measurement_list function calculates the 
actual memory occupied by the IMA logs and compares it with the allocated 
memory. If there is enough memory, it copies all IMA measurement records; 
otherwise, it does not copy any records, which would result in a failure
of remote attestation.

Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: steven chen <chenste@linux.microsoft.com>
---
 security/integrity/ima/ima_kexec.c | 39 ++++++++++++++++++------------
 1 file changed, 24 insertions(+), 15 deletions(-)

diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
index 9d45f4d26f73..8567619889d1 100644
--- a/security/integrity/ima/ima_kexec.c
+++ b/security/integrity/ima/ima_kexec.c
@@ -15,33 +15,41 @@
 #include "ima.h"
 
 #ifdef CONFIG_IMA_KEXEC
+/*
+ * Copy the measurement list to the allocated memory
+ * compare the size of IMA measurement list with the size of the allocated memory
+ *    if the size of the allocated memory is not less than the size of IMA measurement list
+ *        copy the measurement list to the allocated memory.
+ *    else
+ *        return error
+ */
 static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer,
 				     unsigned long segment_size)
 {
+	struct seq_file ima_kexec_file;
 	struct ima_queue_entry *qe;
-	struct seq_file file;
 	struct ima_kexec_hdr khdr;
 	int ret = 0;
 
 	/* segment size can't change between kexec load and execute */
-	file.buf = vmalloc(segment_size);
-	if (!file.buf) {
+	ima_kexec_file.buf = vmalloc(segment_size);
+	if (!ima_kexec_file.buf) {
 		ret = -ENOMEM;
 		goto out;
 	}
 
-	file.file = NULL;
-	file.size = segment_size;
-	file.read_pos = 0;
-	file.count = sizeof(khdr);	/* reserved space */
+	ima_kexec_file.file = NULL;
+	ima_kexec_file.size = segment_size;
+	ima_kexec_file.read_pos = 0;
+	ima_kexec_file.count = sizeof(khdr);	/* reserved space */
 
 	memset(&khdr, 0, sizeof(khdr));
 	khdr.version = 1;
 	/* This is an append-only list, no need to hold the RCU read lock */
 	list_for_each_entry_rcu(qe, &ima_measurements, later, true) {
-		if (file.count < file.size) {
+		if (ima_kexec_file.count < ima_kexec_file.size) {
 			khdr.count++;
-			ima_measurements_show(&file, qe);
+			ima_measurements_show(&ima_kexec_file, qe);
 		} else {
 			ret = -EINVAL;
 			break;
@@ -55,23 +63,24 @@ static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer,
 	 * fill in reserved space with some buffer details
 	 * (eg. version, buffer size, number of measurements)
 	 */
-	khdr.buffer_size = file.count;
+	khdr.buffer_size = ima_kexec_file.count;
 	if (ima_canonical_fmt) {
 		khdr.version = cpu_to_le16(khdr.version);
 		khdr.count = cpu_to_le64(khdr.count);
 		khdr.buffer_size = cpu_to_le64(khdr.buffer_size);
 	}
-	memcpy(file.buf, &khdr, sizeof(khdr));
+	memcpy(ima_kexec_file.buf, &khdr, sizeof(khdr));
 
 	print_hex_dump_debug("ima dump: ", DUMP_PREFIX_NONE, 16, 1,
-			     file.buf, file.count < 100 ? file.count : 100,
+			     ima_kexec_file.buf, ima_kexec_file.count < 100 ?
+			     ima_kexec_file.count : 100,
 			     true);
 
-	*buffer_size = file.count;
-	*buffer = file.buf;
+	*buffer_size = ima_kexec_file.count;
+	*buffer = ima_kexec_file.buf;
 out:
 	if (ret == -EINVAL)
-		vfree(file.buf);
+		vfree(ima_kexec_file.buf);
 	return ret;
 }
 
-- 
2.25.1