vboot: cgpt: Support writing GPT structs to NOR flash

This CL allows the GPT headers and partition entry arrays to be stored
in a NOR flash device. Instead of treating both the NOR and NAND devices
as one (in a sandwich way), this CL writes and reads the GPT structs
independently of the actual device that houses the partitions.
Therefore, the first usable LBA of the partitions will be at 0, and the
last usable LBA is at the end of the NAND.

  +------------------------+
  | NOR houses GPT structs |
  +------------------------+
        |
  0     |  Index into
  v     v
  +------------------------+
  | NAND houses partitions |
  +------------------------+

Note that the "my_lba", "alternate_lba", "entries_lba" in the GPT headers
are no longer meaningful.

Consumers of cgptlib will have to set "stored_on_device" to either
GPT_STORED_ON_DEVICE or GPT_STORED_OFF_DEVICE, and "gpt_drive_sectors"
to the number of 512-byte sectors available to store GPT structs.

The NOR read and write operations are done by "flashrom".

BUG=chromium:425677
BRANCH=none
TEST=unittest
TEST=build with DEBUG, cgpt create/add/show on a stumpy-moblab

Change-Id: I083b3c94da3b0bb3da1a7b10c6969774080a2afd
Reviewed-on: https://chromium-review.googlesource.com/226800
Reviewed-by: Nam Nguyen <namnguyen@chromium.org>
Commit-Queue: Nam Nguyen <namnguyen@chromium.org>
Tested-by: Nam Nguyen <namnguyen@chromium.org>

1 files changed, 101 insertions, 38 deletions

diff --git a/tests/cgptlib_test.c b/tests/cgptlib_test.c
index 363ecc8a..12b366ad 100644
--- a/tests/cgptlib_test.c
+++ b/tests/cgptlib_test.c
@@ -164,7 +164,7 @@ static void BuildTestGptData(GptData *gpt)
 	Guid chromeos_rootfs = GPT_ENT_TYPE_CHROMEOS_ROOTFS;
 
 	gpt->sector_bytes = DEFAULT_SECTOR_SIZE;
-	gpt->drive_sectors = DEFAULT_DRIVE_SECTORS;
+	gpt->drive_sectors = gpt->gpt_drive_sectors = DEFAULT_DRIVE_SECTORS;
 	gpt->current_kernel = CGPT_KERNEL_ENTRY_NOT_FOUND;
 	gpt->valid_headers = MASK_BOTH;
 	gpt->valid_entries = MASK_BOTH;
@@ -353,7 +353,7 @@ static int ParameterTests(void)
 	for (i = 0; i < ARRAY_SIZE(cases); ++i) {
 		BuildTestGptData(gpt);
 		gpt->sector_bytes = cases[i].sector_bytes;
-		gpt->drive_sectors = cases[i].drive_sectors;
+		gpt->drive_sectors = gpt->gpt_drive_sectors = cases[i].drive_sectors;
 		EXPECT(cases[i].expected_retval == CheckParameters(gpt));
 	}
 
@@ -461,15 +461,15 @@ static int SignatureTest(void)
 	GptHeader *h2 = (GptHeader *)gpt->secondary_header;
 	int i;
 
-	EXPECT(1 == CheckHeader(NULL, 0, gpt->drive_sectors));
+	EXPECT(1 == CheckHeader(NULL, 0, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
 
 	for (i = 0; i < 8; ++i) {
 		BuildTestGptData(gpt);
 		h1->signature[i] ^= 0xff;
 		h2->signature[i] ^= 0xff;
 		RefreshCrc32(gpt);
-		EXPECT(1 == CheckHeader(h1, 0, gpt->drive_sectors));
-		EXPECT(1 == CheckHeader(h2, 1, gpt->drive_sectors));
+		EXPECT(1 == CheckHeader(h1, 0, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
+		EXPECT(1 == CheckHeader(h2, 1, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
 	}
 
 	return TEST_OK;
@@ -503,9 +503,9 @@ static int RevisionTest(void)
 		h2->revision = cases[i].value_to_test;
 		RefreshCrc32(gpt);
 
-		EXPECT(CheckHeader(h1, 0, gpt->drive_sectors) ==
+		EXPECT(CheckHeader(h1, 0, gpt->drive_sectors, GPT_STORED_ON_DEVICE) ==
 		       cases[i].expect_rv);
-		EXPECT(CheckHeader(h2, 1, gpt->drive_sectors) ==
+		EXPECT(CheckHeader(h2, 1, gpt->drive_sectors, GPT_STORED_ON_DEVICE) ==
 		       cases[i].expect_rv);
 	}
 	return TEST_OK;
@@ -536,9 +536,9 @@ static int SizeTest(void)
 		h2->size = cases[i].value_to_test;
 		RefreshCrc32(gpt);
 
-		EXPECT(CheckHeader(h1, 0, gpt->drive_sectors) ==
+		EXPECT(CheckHeader(h1, 0, gpt->drive_sectors, GPT_STORED_ON_DEVICE) ==
 		       cases[i].expect_rv);
-		EXPECT(CheckHeader(h2, 1, gpt->drive_sectors) ==
+		EXPECT(CheckHeader(h2, 1, gpt->drive_sectors, GPT_STORED_ON_DEVICE) ==
 		       cases[i].expect_rv);
 	}
 	return TEST_OK;
@@ -555,12 +555,12 @@ static int CrcFieldTest(void)
 	/* Modify a field that the header verification doesn't care about */
 	h1->entries_crc32++;
 	h2->entries_crc32++;
-	EXPECT(1 == CheckHeader(h1, 0, gpt->drive_sectors));
-	EXPECT(1 == CheckHeader(h2, 1, gpt->drive_sectors));
+	EXPECT(1 == CheckHeader(h1, 0, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
+	EXPECT(1 == CheckHeader(h2, 1, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
 	/* Refresh the CRC; should pass now */
 	RefreshCrc32(gpt);
-	EXPECT(0 == CheckHeader(h1, 0, gpt->drive_sectors));
-	EXPECT(0 == CheckHeader(h2, 1, gpt->drive_sectors));
+	EXPECT(0 == CheckHeader(h1, 0, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
+	EXPECT(0 == CheckHeader(h2, 1, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
 
 	return TEST_OK;
 }
@@ -576,8 +576,8 @@ static int ReservedFieldsTest(void)
 	h1->reserved_zero ^= 0x12345678;  /* whatever random */
 	h2->reserved_zero ^= 0x12345678;  /* whatever random */
 	RefreshCrc32(gpt);
-	EXPECT(1 == CheckHeader(h1, 0, gpt->drive_sectors));
-	EXPECT(1 == CheckHeader(h2, 1, gpt->drive_sectors));
+	EXPECT(1 == CheckHeader(h1, 0, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
+	EXPECT(1 == CheckHeader(h2, 1, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
 
 #ifdef PADDING_CHECKED
 	/* TODO: padding check is currently disabled */
@@ -585,8 +585,8 @@ static int ReservedFieldsTest(void)
 	h1->padding[12] ^= 0x34;  /* whatever random */
 	h2->padding[56] ^= 0x78;  /* whatever random */
 	RefreshCrc32(gpt);
-	EXPECT(1 == CheckHeader(h1, 0, gpt->drive_sectors));
-	EXPECT(1 == CheckHeader(h2, 1, gpt->drive_sectors));
+	EXPECT(1 == CheckHeader(h1, 0, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
+	EXPECT(1 == CheckHeader(h2, 1, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
 #endif
 
 	return TEST_OK;
@@ -624,9 +624,9 @@ static int SizeOfPartitionEntryTest(void) {
 			cases[i].value_to_test;
 		RefreshCrc32(gpt);
 
-		EXPECT(CheckHeader(h1, 0, gpt->drive_sectors) ==
+		EXPECT(CheckHeader(h1, 0, gpt->drive_sectors, GPT_STORED_ON_DEVICE) ==
 		       cases[i].expect_rv);
-		EXPECT(CheckHeader(h2, 1, gpt->drive_sectors) ==
+		EXPECT(CheckHeader(h2, 1, gpt->drive_sectors, GPT_STORED_ON_DEVICE) ==
 		       cases[i].expect_rv);
 	}
 
@@ -647,8 +647,11 @@ static int NumberOfPartitionEntriesTest(void)
 	h1->number_of_entries--;
 	h2->number_of_entries /= 2;
 	RefreshCrc32(gpt);
-	EXPECT(1 == CheckHeader(h1, 0, gpt->drive_sectors));
-	EXPECT(1 == CheckHeader(h2, 1, gpt->drive_sectors));
+	EXPECT(1 == CheckHeader(h1, 0, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
+	EXPECT(1 == CheckHeader(h2, 1, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
+	/* But it's okay to have less if the GPT structs are stored elsewhere. */
+	EXPECT(0 == CheckHeader(h1, 0, gpt->drive_sectors, GPT_STORED_OFF_DEVICE));
+	EXPECT(0 == CheckHeader(h2, 1, gpt->drive_sectors, GPT_STORED_OFF_DEVICE));
 
 	return TEST_OK;
 }
@@ -663,37 +666,37 @@ static int MyLbaTest(void)
 
 	/* myLBA depends on primary vs secondary flag */
 	BuildTestGptData(gpt);
-	EXPECT(1 == CheckHeader(h1, 1, gpt->drive_sectors));
-	EXPECT(1 == CheckHeader(h2, 0, gpt->drive_sectors));
+	EXPECT(1 == CheckHeader(h1, 1, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
+	EXPECT(1 == CheckHeader(h2, 0, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
 
 	BuildTestGptData(gpt);
 	h1->my_lba--;
 	h2->my_lba--;
 	RefreshCrc32(gpt);
-	EXPECT(1 == CheckHeader(h1, 0, gpt->drive_sectors));
-	EXPECT(1 == CheckHeader(h2, 1, gpt->drive_sectors));
+	EXPECT(1 == CheckHeader(h1, 0, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
+	EXPECT(1 == CheckHeader(h2, 1, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
 
 	BuildTestGptData(gpt);
 	h1->my_lba = 2;
 	h2->my_lba--;
 	RefreshCrc32(gpt);
-	EXPECT(1 == CheckHeader(h1, 0, gpt->drive_sectors));
-	EXPECT(1 == CheckHeader(h2, 1, gpt->drive_sectors));
+	EXPECT(1 == CheckHeader(h1, 0, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
+	EXPECT(1 == CheckHeader(h2, 1, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
 
 	/* We should ignore the alternate_lba field entirely */
 	BuildTestGptData(gpt);
 	h1->alternate_lba++;
 	h2->alternate_lba++;
 	RefreshCrc32(gpt);
-	EXPECT(0 == CheckHeader(h1, 0, gpt->drive_sectors));
-	EXPECT(0 == CheckHeader(h2, 1, gpt->drive_sectors));
+	EXPECT(0 == CheckHeader(h1, 0, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
+	EXPECT(0 == CheckHeader(h2, 1, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
 
 	BuildTestGptData(gpt);
 	h1->alternate_lba--;
 	h2->alternate_lba--;
 	RefreshCrc32(gpt);
-	EXPECT(0 == CheckHeader(h1, 0, gpt->drive_sectors));
-	EXPECT(0 == CheckHeader(h2, 1, gpt->drive_sectors));
+	EXPECT(0 == CheckHeader(h1, 0, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
+	EXPECT(0 == CheckHeader(h2, 1, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
 
 	BuildTestGptData(gpt);
 	h1->entries_lba++;
@@ -703,19 +706,19 @@ static int MyLbaTest(void)
 	 * We support a padding between primary GPT header and its entries. So
 	 * this still passes.
 	 */
-	EXPECT(0 == CheckHeader(h1, 0, gpt->drive_sectors));
+	EXPECT(0 == CheckHeader(h1, 0, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
 	/*
 	 * But the secondary table should fail because it would overlap the
 	 * header, which is now lying after its entry array.
 	 */
-	EXPECT(1 == CheckHeader(h2, 1, gpt->drive_sectors));
+	EXPECT(1 == CheckHeader(h2, 1, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
 
 	BuildTestGptData(gpt);
 	h1->entries_lba--;
 	h2->entries_lba--;
 	RefreshCrc32(gpt);
-	EXPECT(1 == CheckHeader(h1, 0, gpt->drive_sectors));
-	EXPECT(1 == CheckHeader(h2, 1, gpt->drive_sectors));
+	EXPECT(1 == CheckHeader(h1, 0, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
+	EXPECT(1 == CheckHeader(h2, 1, gpt->drive_sectors, GPT_STORED_ON_DEVICE));
 
 	return TEST_OK;
 }
@@ -723,7 +726,8 @@ static int MyLbaTest(void)
 /* Test if FirstUsableLBA and LastUsableLBA are checked.
  * FirstUsableLBA must be after the end of the primary GPT table array.
  * LastUsableLBA must be before the start of the secondary GPT table array.
- * FirstUsableLBA <= LastUsableLBA. */
+ * FirstUsableLBA <= LastUsableLBA.
+ * Also see CheckHeaderOffDevice() test. */
 static int FirstUsableLbaAndLastUsableLbaTest(void)
 {
 	GptData *gpt = GetEmptyGptData();
@@ -763,9 +767,9 @@ static int FirstUsableLbaAndLastUsableLbaTest(void)
 		h2->last_usable_lba = cases[i].secondary_last_usable_lba;
 		RefreshCrc32(gpt);
 
-		EXPECT(CheckHeader(h1, 0, gpt->drive_sectors) ==
+		EXPECT(CheckHeader(h1, 0, gpt->drive_sectors, GPT_STORED_ON_DEVICE) ==
 		       cases[i].primary_rv);
-		EXPECT(CheckHeader(h2, 1, gpt->drive_sectors) ==
+		EXPECT(CheckHeader(h2, 1, gpt->drive_sectors, GPT_STORED_ON_DEVICE) ==
 		       cases[i].secondary_rv);
 	}
 
@@ -1966,6 +1970,64 @@ static int MtdFtsTest() {
   return TEST_OK;
 }
 
+static int CheckHeaderOffDevice()
+{
+	GptData* gpt = GetEmptyGptData();
+	BuildTestGptData(gpt);
+
+	GptHeader* primary_header = (GptHeader*)gpt->primary_header;
+	primary_header->first_usable_lba = 0;
+	RefreshCrc32(gpt);
+	// GPT is stored on the same device so first usable lba should not
+	// start at 0.
+	EXPECT(1 == CheckHeader(primary_header, 0, gpt->drive_sectors,
+		GPT_STORED_ON_DEVICE));
+	// But off device, it is okay to accept this GPT header.
+	EXPECT(0 == CheckHeader(primary_header, 0, gpt->drive_sectors,
+		GPT_STORED_OFF_DEVICE));
+
+	BuildTestGptData(gpt);
+	primary_header->number_of_entries = 100;
+	RefreshCrc32(gpt);
+	// Normally, number of entries is 128. So this should fail.
+	EXPECT(1 == CheckHeader(primary_header, 0, gpt->drive_sectors,
+		GPT_STORED_ON_DEVICE));
+	// But off device, it is okay.
+	EXPECT(0 == CheckHeader(primary_header, 0, gpt->drive_sectors,
+		GPT_STORED_OFF_DEVICE));
+
+	primary_header->number_of_entries = MIN_NUMBER_OF_ENTRIES - 1;
+	RefreshCrc32(gpt);
+	// However, too few entries is not good.
+	EXPECT(1 == CheckHeader(primary_header, 0, gpt->drive_sectors,
+		GPT_STORED_OFF_DEVICE));
+
+	// Repeat for secondary header.
+	BuildTestGptData(gpt);
+	GptHeader* secondary_header = (GptHeader*)gpt->secondary_header;
+	secondary_header->first_usable_lba = 0;
+	RefreshCrc32(gpt);
+	EXPECT(1 == CheckHeader(secondary_header, 1, gpt->drive_sectors,
+		GPT_STORED_ON_DEVICE));
+	EXPECT(0 == CheckHeader(secondary_header, 1, gpt->drive_sectors,
+		GPT_STORED_OFF_DEVICE));
+
+	BuildTestGptData(gpt);
+	secondary_header->number_of_entries = 100;
+	RefreshCrc32(gpt);
+	EXPECT(1 == CheckHeader(secondary_header, 1, gpt->drive_sectors,
+		GPT_STORED_ON_DEVICE));
+	EXPECT(0 == CheckHeader(secondary_header, 1, gpt->drive_sectors,
+		GPT_STORED_OFF_DEVICE));
+
+	secondary_header->number_of_entries = MIN_NUMBER_OF_ENTRIES - 1;
+	RefreshCrc32(gpt);
+	EXPECT(1 == CheckHeader(secondary_header, 1, gpt->drive_sectors,
+		GPT_STORED_OFF_DEVICE));
+
+	return TEST_OK;
+}
+
 int main(int argc, char *argv[])
 {
 	int i;
@@ -2013,6 +2075,7 @@ int main(int argc, char *argv[])
 		{ TEST_CASE(GetKernelGuidTest), },
 		{ TEST_CASE(ErrorTextTest), },
 		{ TEST_CASE(MtdFtsTest), },
+		{ TEST_CASE(CheckHeaderOffDevice), },
 	};
 
 	for (i = 0; i < sizeof(test_cases)/sizeof(test_cases[0]); ++i) {