From 44b6b87610281a4add36a1addd7630095dc8a545 Mon Sep 17 00:00:00 2001

From: Pawel Baldysiak <pawel.baldysiak@intel.com>

Date: Thu, 28 Sep 2017 14:41:10 +0200

Subject: [PATCH 04/12] imsm: validate multiple ppls during assemble

Change validation algorithm to check validity of multiple ppls that

are stored in PPL area.

If read error occurs during - treat the all PPLs as invalid -

there is no guarantee that this one was not latest. If the header CRC is

incorrect - assume that there are no further PPLs in PPL area.

If whole PPL area was written at least once - there is a possibility that

old PPL (with lower generation number) will follow the recent one

(with higest generation number). Compare those generation numbers to check

which PPL is latest.

Signed-off-by: Pawel Baldysiak <pawel.baldysiak@intel.com>

Signed-off-by: Jes Sorensen <jsorensen@fb.com>

---

 super-intel.c | 71 +++++++++++++++++++++++++++++++++++++++--------------------

 1 file changed, 47 insertions(+), 24 deletions(-)

diff --git a/super-intel.c b/super-intel.c

index 347838e..56dec36 100644

--- a/super-intel.c

+++ b/super-intel.c

@@ -6106,11 +6106,14 @@ static int validate_ppl_imsm(struct supertype *st, struct mdinfo *info,

 	struct imsm_dev *dev;

 	struct imsm_map *map;

 	__u32 idx;

+	unsigned int i;

+	unsigned long long ppl_offset = 0;

+	unsigned long long prev_gen_num = 0;

 	if (disk->disk.raid_disk < 0)

 		return 0;

-	if (posix_memalign(&buf, 4096, PPL_HEADER_SIZE)) {

+	if (posix_memalign(&buf, MAX_SECTOR_SIZE, PPL_HEADER_SIZE)) {

 		pr_err("Failed to allocate PPL header buffer\n");

 		return -1;

 	}

@@ -6123,34 +6126,54 @@ static int validate_ppl_imsm(struct supertype *st, struct mdinfo *info,

 	if (!d || d->index < 0 || is_failed(&d->disk))

 		goto out;

-	if (lseek64(d->fd, info->ppl_sector * 512, SEEK_SET) < 0) {

-		perror("Failed to seek to PPL header location");

-		ret = -1;

-		goto out;

-	}

+	ret = 1;

+	while (ppl_offset < MULTIPLE_PPL_AREA_SIZE_IMSM) {

+		dprintf("Checking potential PPL at offset: %llu\n", ppl_offset);

-	if (read(d->fd, buf, PPL_HEADER_SIZE) != PPL_HEADER_SIZE) {

-		perror("Read PPL header failed");

-		ret = -1;

-		goto out;

-	}

+		if (lseek64(d->fd, info->ppl_sector * 512 + ppl_offset,

+			    SEEK_SET) < 0) {

+			perror("Failed to seek to PPL header location");

+			ret = -1;

+			goto out;

+		}

-	ppl_hdr = buf;

+		if (read(d->fd, buf, PPL_HEADER_SIZE) != PPL_HEADER_SIZE) {

+			perror("Read PPL header failed");

+			ret = -1;

+			goto out;

+		}

-	crc = __le32_to_cpu(ppl_hdr->checksum);

-	ppl_hdr->checksum = 0;

+		ppl_hdr = buf;

-	if (crc != ~crc32c_le(~0, buf, PPL_HEADER_SIZE)) {

-		dprintf("Wrong PPL header checksum on %s\n",

-			d->devname);

-		ret = 1;

-	}

+		crc = __le32_to_cpu(ppl_hdr->checksum);

+		ppl_hdr->checksum = 0;

+

+		if (crc != ~crc32c_le(~0, buf, PPL_HEADER_SIZE)) {

+			dprintf("Wrong PPL header checksum on %s\n",

+				d->devname);

+			goto out;

+		}

+

+		if (prev_gen_num > __le64_to_cpu(ppl_hdr->generation)) {

+			/* previous was newest, it was already checked */

+			goto out;

+		}

+

+		if ((__le32_to_cpu(ppl_hdr->signature) !=

+			      super->anchor->orig_family_num)) {

+			dprintf("Wrong PPL header signature on %s\n",

+				d->devname);

+			ret = 1;

+			goto out;

+		}

+

+		ret = 0;

+		prev_gen_num = __le64_to_cpu(ppl_hdr->generation);

-	if (!ret && (__le32_to_cpu(ppl_hdr->signature) !=

-		      super->anchor->orig_family_num)) {

-		dprintf("Wrong PPL header signature on %s\n",

-			d->devname);

-		ret = 1;

+		ppl_offset += PPL_HEADER_SIZE;

+		for (i = 0; i < __le32_to_cpu(ppl_hdr->entries_count); i++)

+			ppl_offset +=

+				   __le32_to_cpu(ppl_hdr->entries[i].pp_size);

 	}

 out:

-- 

2.7.4