1 files changed, 76 insertions, 19 deletions

diff --git a/futility/cmd_validate_rec_mrc.c b/futility/cmd_validate_rec_mrc.c
index 3013891a..1fdd47c1 100644
--- a/futility/cmd_validate_rec_mrc.c
+++ b/futility/cmd_validate_rec_mrc.c
@@ -35,19 +35,22 @@ static void print_help(int argc, char *argv[])
 	printf("\n");
 }
 
-struct mrc_cache {
+struct mrc_metadata {
 	uint32_t signature;
-	uint32_t size;
-	uint32_t checksum;
+	uint32_t data_size;
+	uint16_t data_checksum;
+	uint16_t header_checksum;
 	uint32_t version;
-	uint8_t  data[0];
 } __attribute__((packed));
 
 #define MRC_DATA_SIGNATURE	(('M'<<0)|('R'<<8)|('C'<<16)|('D'<<24))
+#define REGF_BLOCK_SHIFT	4
+#define REGF_UNALLOCATED_BLOCK	0xffff
 
-unsigned long compute_ip_checksum(void *addr, unsigned long length)
+
+unsigned long compute_ip_checksum(const void *addr, unsigned long length)
 {
-	uint8_t *ptr;
+	const uint8_t *ptr;
 	volatile union {
 		uint8_t  byte[2];
 		uint16_t word;
@@ -77,29 +80,71 @@ unsigned long compute_ip_checksum(void *addr, unsigned long length)
 	return (~value.word) & 0xFFFF;
 }
 
-static int verify_checksum(struct mrc_cache *cache, unsigned long cache_len)
+static int verify_mrc_slot(struct mrc_metadata *md, unsigned long slot_len)
 {
-	uint32_t checksum;
-	if (cache->signature != MRC_DATA_SIGNATURE) {
+	uint32_t header_checksum;
+	if (md->signature != MRC_DATA_SIGNATURE) {
 		fprintf(stderr, "MRC signature mismatch\n");
 		return 1;
 	}
 
 	fprintf(stderr, "MRC signature match.. successful\n");
 
-	if (cache->size > cache_len) {
+	if (md->data_size > slot_len) {
 		fprintf(stderr, "MRC cache size overflow\n");
 		return 1;
 	}
 
-	checksum = compute_ip_checksum((void *)&cache->data[0], cache->size);
+	header_checksum = md->header_checksum;
+	md->header_checksum = 0;
+
+	if (header_checksum != compute_ip_checksum(md, sizeof(*md))) {
+		fprintf(stderr, "MRC metadata header checksum mismatch\n");
+		return 1;
+	}
+
+	md->header_checksum = header_checksum;
+
+	fprintf(stderr, "MRC metadata header checksum.. verified!\n");
 
-	if (checksum != cache->checksum) {
-		fprintf(stderr, "MRC checksum mismatch\n");
+	if (md->data_checksum != compute_ip_checksum(&md[1], md->data_size)) {
+		fprintf(stderr, "MRC data checksum mismatch\n");
+		return 1;
+	}
+
+	fprintf(stderr, "MRC data checksum.. verified!\n");
+	return 0;
+}
+
+static int get_mrc_data_slot(uint16_t *mb, uint32_t *data_offset,
+			     uint32_t *data_size)
+{
+	/*
+	 * First block offset in metadata block tells the total number of
+	 * metadata blocks.
+	 * Currently, we expect only 1 metadata block to be present.
+	 */
+	if (*mb != 1) {
+		fprintf(stderr, "Only 1 metadata block is expected. "
+			"Actual %x\n", *mb);
+		return 1;
+	}
+
+	/*
+	 * RECOVERY_MRC_CACHE is expected to contain only one slot. Thus, there
+	 * should be only one block offset present, indicating size of the MRC
+	 * cache slot.
+	 */
+	mb++;
+	*data_offset = (1 << REGF_BLOCK_SHIFT);
+	*data_size = (*mb - 1) << REGF_BLOCK_SHIFT;
+
+	mb++;
+	if (*mb != REGF_UNALLOCATED_BLOCK) {
+		fprintf(stderr, "More than 1 slot in recovery mrc cache.\n");
 		return 1;
 	}
 
-	fprintf(stderr, "MRC checksum.. verified!\n");
 	return 0;
 }
 
@@ -111,6 +156,8 @@ static int do_validate_rec_mrc(int argc, char *argv[])
 	uint32_t file_size;
 	uint8_t *buff;
 	uint32_t offset = 0;
+	uint32_t data_offset;
+	uint32_t data_size;
 	char *e;
 
 	while (((i = getopt_long(argc, argv, ":", long_opts, NULL)) != -1) &&
@@ -162,12 +209,22 @@ static int do_validate_rec_mrc(int argc, char *argv[])
 		return 1;
 	}
 
-	if (file_size > offset)
-		ret = verify_checksum((struct mrc_cache *)(buff + offset),
-				      file_size - offset);
+	if (get_mrc_data_slot((uint16_t *)(buff + offset), &data_offset,
+			      &data_size)) {
+		fprintf(stderr, "Metadata block error\n");
+		futil_unmap_file(fd, MAP_RO, buff, file_size);
+		close(fd);
+		return 1;
+	}
+	offset += data_offset;
+
+	if ((file_size > offset) && ((file_size - offset) >= data_size))
+		ret = verify_mrc_slot((struct mrc_metadata *)(buff + offset),
+				      data_size);
 	else
-		fprintf(stderr, "Offset greater than file size: offset=0x%x, "
-			"file size=0x%x\n", offset, file_size);
+		fprintf(stderr, "Offset or data size greater than file size: "
+			"offset=0x%x, file size=0x%x, data_size=0x%x\n",
+			offset, file_size, data_size);
 
 	if (futil_unmap_file(fd, MAP_RO, buff, file_size) != FILE_ERR_NONE) {
 		fprintf(stderr, "Failed to unmap file %s\n", infile);