bdb: Add secret deriving code for SP-RO

This patch adds code which dervies secrets from BDS. It's supposed to be
done by SP-RO, hence the code is mostly useful for testing (or emulation).

vba_extend_secrets_ro takes a function pointer to a hash extend
function. It'll be used to try different sha256 extend algorithms.

BUG=chromium:649555
BRANCH=none
TEST=make runtests

Change-Id: I8fef6b851fb84686d8bcdd948b36160016687c51
Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/384354
Reviewed-by: Randall Spangler <rspangler@chromium.org>

1 files changed, 251 insertions, 22 deletions

diff --git a/firmware/bdb/secrets.c b/firmware/bdb/secrets.c
index 08bca5f5..bd6c6fcf 100644
--- a/firmware/bdb/secrets.c
+++ b/firmware/bdb/secrets.c
@@ -11,8 +11,137 @@
 #include "bdb.h"
 #include "secrets.h"
 
-static int get_constant(const uint8_t *buf, uint32_t buf_size,
-			const uint8_t *constant, uint8_t *out)
+const uint8_t secret_constant_a[] = {
+	0xad, 0xf8, 0xd1, 0xd9, 0x48, 0xe6, 0xb3, 0xe4, 0xe0, 0xc4,
+	0xd8, 0x66, 0x97, 0x95, 0x71, 0xa8, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0x01};
+
+const uint8_t secret_constant_b[] = {
+	0xba, 0x9d, 0x1d, 0x8b, 0x12, 0xbd, 0x8d, 0xcd, 0x4c, 0x89,
+	0xd8, 0x18, 0x72, 0x98, 0xb5, 0x18, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0x02};
+
+const uint8_t secret_constant_x[] = {
+	0xfd, 0xc1, 0xe5, 0x57, 0x34, 0xf4, 0xf6, 0x89, 0x6d, 0x1b,
+	0x6f, 0xf2, 0xd0, 0x36, 0xdb, 0xf4, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0x09};
+
+const uint8_t secret_constant_y[] = {
+	0x18, 0xef, 0x01, 0x8e, 0xcd, 0x62, 0xf1, 0xb0, 0x2d, 0xd4,
+	0x11, 0xa4, 0xb5, 0x6e, 0x38, 0xf6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0x0a};
+
+const uint8_t secret_constant_c[] = {
+	0x46, 0xda, 0x52, 0x8d, 0x08, 0x56, 0x14, 0xde, 0x75, 0x9c,
+	0x9a, 0xeb, 0x08, 0x93, 0x3d, 0xd6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0x0b};
+
+const uint8_t secret_constant_fv0[] = {
+	0x93, 0x32, 0xf7, 0x8d, 0xec, 0x4b, 0x26, 0x2e, 0xb3, 0x5c,
+	0x39, 0xd7, 0xfc, 0xc6, 0x9f, 0x09, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0x05};
+
+const uint8_t secret_constant_fv1[] = {
+	0x60, 0x8d, 0x96, 0x35, 0xdf, 0xf6, 0x31, 0x67, 0xab, 0xb8,
+	0x9f, 0x50, 0x81, 0x28, 0x82, 0xec, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0x06};
+
+const uint8_t secret_constant_kv0[] = {
+	0x46, 0x6d, 0xef, 0x2c, 0x05, 0xc9, 0xbf, 0xa9, 0x6b, 0xee,
+	0xaa, 0x6c, 0xb9, 0xb4, 0x6d, 0x37, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0x07};
+
+const uint8_t secret_constant_kv1[] = {
+	0x0a, 0x9e, 0xc9, 0x20, 0x29, 0xa3, 0x5d, 0xd7, 0x27, 0x55,
+	0xb6, 0xa6, 0xb4, 0x80, 0x7c, 0x73, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0x08};
+
+const uint8_t secret_constant_k[] = {
+	/*
+	 * Digest of kernel data key struct fills first 32 bytes
+	 */
+	            0x1e, 0x1d, 0xec, 0xf2, 0x6d, 0x27, 0xa6, 0xd9,
+	0x67, 0x0f, 0x34, 0xc5, 0xfa, 0x01, 0x68, 0xf6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0x03};
+
+const uint8_t secret_constant_l[] = {
+	/*
+	 * Digest of kernel data key struct fills first 32 bytes
+	 */
+	            0x9b, 0xc0, 0x29, 0xd3, 0xc3, 0x90, 0x7f, 0x82,
+	0x56, 0xe2, 0x67, 0x79, 0x11, 0x74, 0xbe, 0xd0, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0x04};
+
+const uint8_t secret_constant_p[] = {
+	/*
+	 * Digest of KDB key struct fills first 32 bytes
+	 */
+	            0xfe, 0x31, 0xed, 0xed, 0x45, 0xfd, 0x8a, 0x5d,
+	0x87, 0x90, 0xac, 0x17, 0x02, 0x89, 0x2c, 0xba, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0x0c};
+
+const uint8_t secret_constant_q[] = {
+	/*
+	 * Digest of KDB key struct fills first 32 bytes
+	 */
+	            0xc7, 0x60, 0x83, 0x0f, 0x20, 0x44, 0x5d, 0x9c,
+	0x70, 0x96, 0x05, 0x2d, 0x51, 0x4b, 0x15, 0x99, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6, 0xc6,
+	0xc6, 0xc6, 0xc6, 0x0d};
+
+/**
+ * Get constant with digest
+ *
+ * This function computes a digest of the given buffer and concatenates it
+ * to the given constant.
+ *
+ * @param buf		Data from which a digest is computed
+ * @param buf_size	Size of <buf>
+ * @param constant	Buffer containing constant
+ * @param out		Buffer where the result is stored
+ * @return		BDB_SUCCESS on success or !BDB_SUCCESS otherwise
+ */
+static int get_constant_with_digest(const uint8_t *buf, uint32_t buf_size,
+				    const uint8_t *constant, uint8_t *out)
 {
 	int digest_size = vb2_digest_size(VB2_HASH_SHA256);
 	const struct bdb_key *key = (const struct bdb_key *)buf;
@@ -32,42 +161,120 @@ static int get_constant(const uint8_t *buf, uint32_t buf_size,
 	return BDB_SUCCESS;
 }
 
+/**
+ * Derive secrets for SP-RO
+ *
+ * This function extends a BDS to derive secrets as done by SP-RO (a.k.a. mask
+ * rom).
+ *
+ * @param ctx		VBoot context
+ * @param type		Type of secret to derive
+ * @param wsr		Work secret register
+ * @param buf		Data from which a digest is computed
+ * @param buf_size	Size of <buf>
+ * @param extend	sha256 extension function to be used
+ * @return		BDB_SUCCESS on success or BDB_ERROR_* otherwise
+ */
+static int derive_secret_ro(struct vba_context *ctx, enum bdb_secret_type type,
+			    uint8_t *wsr, const uint8_t *buf, uint32_t buf_size,
+			    f_extend extend)
+{
+	uint8_t c[BDB_CONSTANT_BLOCK_SIZE];
+	uint8_t *from;
+	const uint8_t *by = (const uint8_t *)c;
+	uint8_t *to;
+
+	switch (type) {
+	case BDB_SECRET_TYPE_WSR:
+		from = to = wsr;
+		by = secret_constant_x;
+		break;
+	case BDB_SECRET_TYPE_BDB:
+		from = wsr;
+		to = ctx->secrets->bdb;
+		if (get_constant_with_digest(buf, buf_size,
+					     secret_constant_p, c))
+			return BDB_ERROR_SECRET_BDB;
+		break;
+	case BDB_SECRET_TYPE_BOOT_PATH:
+		from = wsr;
+		to = ctx->secrets->boot_path;
+		if (get_constant_with_digest(buf, buf_size,
+					     secret_constant_k, c))
+			return BDB_ERROR_SECRET_BOOT_PATH;
+		break;
+	case BDB_SECRET_TYPE_BOOT_VERIFIED:
+		from = wsr;
+		to = ctx->secrets->boot_verified;
+		if (ctx->flags & VBA_CONTEXT_FLAG_BDB_KEY_EFUSED)
+			by = secret_constant_fv0;
+		else
+			by = secret_constant_fv1;
+		break;
+	case BDB_SECRET_TYPE_NVM_WP:
+		from = wsr;
+		by = secret_constant_a;
+		to = ctx->secrets->nvm_wp;
+		break;
+	case BDB_SECRET_TYPE_NVM_RW:
+		from = ctx->secrets->nvm_wp;
+		by = secret_constant_b;
+		to = ctx->secrets->nvm_rw;
+		break;
+	default:
+		return BDB_ERROR_SECRET_TYPE;
+	}
+
+	if (extend)
+		extend(from, by, to);
+	else
+		vb2_sha256_extend(from, by, to);
+
+	return BDB_SUCCESS;
+}
+
 int vba_derive_secret(struct vba_context *ctx, enum bdb_secret_type type,
-		      const uint8_t *buf, uint32_t buf_size)
+		      uint8_t *wsr, const uint8_t *buf, uint32_t buf_size)
 {
 	uint8_t c[BDB_CONSTANT_BLOCK_SIZE];
-	const uint8_t *b = (const uint8_t *)c;
-	uint8_t *s;
-	uint8_t *o;
+	uint8_t *from;
+	const uint8_t *by = (const uint8_t *)c;
+	uint8_t *to;
 
 	switch (type) {
+	case BDB_SECRET_TYPE_WSR:
+		from = to = wsr;
+		by = secret_constant_y;
+		break;
 	case BDB_SECRET_TYPE_BDB:
-		s = o = ctx->ro_secrets->bdb;
-		if (get_constant(buf, buf_size, secret_constant_q, c))
+		from = to = ctx->secrets->bdb;
+		if (get_constant_with_digest(buf, buf_size,
+					     secret_constant_q, c))
 			return BDB_ERROR_SECRET_BDB;
 		break;
 	case BDB_SECRET_TYPE_BOOT_PATH:
-		s = o = ctx->ro_secrets->boot_path;
-		if (get_constant(buf, buf_size, secret_constant_l, c))
+		from = to = ctx->secrets->boot_path;
+		if (get_constant_with_digest(buf, buf_size,
+					     secret_constant_l, c))
 			return BDB_ERROR_SECRET_BOOT_PATH;
 		break;
 	case BDB_SECRET_TYPE_BOOT_VERIFIED:
-		s = o = ctx->ro_secrets->boot_verified;
+		from = to = ctx->secrets->boot_verified;
 		if (ctx->flags & VBA_CONTEXT_FLAG_KERNEL_DATA_KEY_VERIFIED)
-			b = secret_constant_kv1;
+			by = secret_constant_kv1;
 		else
-			b = secret_constant_kv0;
+			by = secret_constant_kv0;
 		break;
 	case BDB_SECRET_TYPE_BUC:
-		s = ctx->ro_secrets->boot_verified;
-		b = secret_constant_c;
-		o = ctx->rw_secrets->buc;
+		from = ctx->secrets->boot_verified;
+		by = secret_constant_c;
+		to = ctx->secrets->buc;
 		break;
 	default:
 		return BDB_ERROR_SECRET_TYPE;
 	}
 
-	vb2_sha256_extend(s, b, o);
+	vb2_sha256_extend(from, by, to);
 
 	return BDB_SUCCESS;
 }
@@ -78,19 +285,19 @@ int vba_clear_secret(struct vba_context *ctx, enum bdb_secret_type type)
 
 	switch (type) {
 	case BDB_SECRET_TYPE_NVM_RW:
-		s = ctx->ro_secrets->nvm_rw;
+		s = ctx->secrets->nvm_rw;
 		break;
 	case BDB_SECRET_TYPE_BDB:
-		s = ctx->ro_secrets->bdb;
+		s = ctx->secrets->bdb;
 		break;
 	case BDB_SECRET_TYPE_BOOT_PATH:
-		s = ctx->ro_secrets->boot_path;
+		s = ctx->secrets->boot_path;
 		break;
 	case BDB_SECRET_TYPE_BOOT_VERIFIED:
-		s = ctx->ro_secrets->boot_verified;
+		s = ctx->secrets->boot_verified;
 		break;
 	case BDB_SECRET_TYPE_BUC:
-		s = ctx->rw_secrets->buc;
+		s = ctx->secrets->buc;
 		break;
 	default:
 		return BDB_ERROR_SECRET_TYPE;
@@ -99,3 +306,25 @@ int vba_clear_secret(struct vba_context *ctx, enum bdb_secret_type type)
 	memset(s, 0, BDB_SECRET_SIZE);
 	return BDB_SUCCESS;
 }
+
+int vba_extend_secrets_ro(struct vba_context *ctx, const uint8_t *bdb,
+			  uint8_t *wsr, f_extend extend)
+{
+	const struct bdb_key *bdbkey = bdb_get_bdbkey(bdb);
+	const struct bdb_key *datakey = bdb_get_datakey(bdb);
+
+	derive_secret_ro(ctx, BDB_SECRET_TYPE_BDB, wsr, (const uint8_t *)bdbkey,
+			 bdbkey->struct_size, extend);
+	derive_secret_ro(ctx, BDB_SECRET_TYPE_BOOT_PATH, wsr,
+			 (const uint8_t *)datakey, datakey->struct_size,
+			 extend);
+	derive_secret_ro(ctx, BDB_SECRET_TYPE_BOOT_VERIFIED, wsr, NULL, 0,
+			 extend);
+	derive_secret_ro(ctx, BDB_SECRET_TYPE_NVM_WP, wsr, NULL, 0, extend);
+	/* Deriving NVM-RW has to be done after NVM-WP */
+	derive_secret_ro(ctx, BDB_SECRET_TYPE_NVM_RW, wsr, NULL, 0, extend);
+	/* Extending WSR has to be done last. */
+	derive_secret_ro(ctx, BDB_SECRET_TYPE_WSR, wsr, NULL, 0, extend);
+
+	return BDB_SUCCESS;
+}