Rewrite algorithm type parsers and make them globally available

There is some code strewn around between futility and the vb21-specific
part of hostlib to allow parsing of textual algorithm names to vboot
enums, but it is somewhat disorganized and not written in a super
efficient way. This patch rewrites it and centralizes all the algorithm
mapping stuff under 2crypto.c so it can be a single source of truth for
all of vboot. (String parsing routines still need to stay in hostlib
since not all firmware targets support things like stroul() and
strcasecmp().)

BRANCH=None
BUG=None
TEST=make runtests

Signed-off-by: Julius Werner <jwerner@chromium.org>
Change-Id: I719b2499992a6e4395a29231bc8b9a7680c5b174
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/2099447
Reviewed-by: Joel Kitching <kitching@chromium.org>
Commit-Queue: Joel Kitching <kitching@chromium.org>

5 files changed, 67 insertions, 158 deletions

diff --git a/host/include/vboot_host.h b/host/include/vboot_host.h
index 81c5434f..328c063b 100644
--- a/host/include/vboot_host.h
+++ b/host/include/vboot_host.h
@@ -9,14 +9,16 @@
 #define VBOOT_REFERENCE_VBOOT_HOST_H_
 
 #include <inttypes.h>
+#include <stdbool.h>
 #include <stdint.h>
 #include <stdlib.h>
 
+#include "2crypto.h"
+#include "cgpt_params.h"
+
 /****************************************************************************/
 /* EFI GPT manipulation */
 
-#include "cgpt_params.h"
-
 #ifdef __cplusplus
 extern "C" {
 #endif  /* __cplusplus */
@@ -73,6 +75,24 @@ char *FindKernelConfig(const char *filename,
 int ExtractVmlinuz(void *kpart_data, size_t kpart_size,
 		   void **vmlinuz_out, size_t *vmlinuz_size);
 
+/**
+ * Look up a signature algorithm by its string representation.
+ *
+ * @param str		String representation of algo (e.g. "rsa2048" or "1")
+ * @param alg		Output parameter that will be filled with found enum
+ * @return		True if algorithm was found, false otherwise.
+ */
+bool vb2_lookup_sig_alg(const char *str, enum vb2_signature_algorithm *sig_alg);
+
+/**
+ * Look up a hash algorithm by its string representation.
+ *
+ * @param str		String representation of algorithm (e.g. "sha1" or "1")
+ * @param alg		Output parameter that will be filled with found enum
+ * @return		True if algorithm was found, false otherwise.
+ */
+bool vb2_lookup_hash_alg(const char *str, enum vb2_hash_algorithm *hash_alg);
+
 #ifdef __cplusplus
 }
 #endif  /* __cplusplus */
diff --git a/host/lib/crypto.c b/host/lib/crypto.c
new file mode 100644
index 00000000..7103ed8a
--- /dev/null
+++ b/host/lib/crypto.c
@@ -0,0 +1,44 @@
+/* Copyright 2020 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include <stdlib.h>
+#include <strings.h>
+
+#include "vboot_host.h"
+
+static int lookup_helper(const char *str, const char *table[], size_t size,
+			 unsigned int *out)
+{
+	unsigned int algo;
+	char *e;
+
+	/* try string first */
+	for (algo = 0; algo < size; algo++)
+		if (table[algo] && !strcasecmp(table[algo], str))
+			goto found;
+
+	/* fine, try number */
+	algo = strtoul(str, &e, 0);
+	if (!*str || (e && *e))
+		/* that's not a number */
+		return false;
+	if (algo >= size || !table[algo])
+		/* that's not a valid algorithm */
+		return false;
+
+ found:
+	*out = algo;
+	return true;
+}
+
+bool vb2_lookup_sig_alg(const char *str, enum vb2_signature_algorithm *sig_alg)
+{
+	return lookup_helper(str, vb2_sig_names, VB2_SIG_ALG_COUNT, sig_alg);
+}
+
+bool vb2_lookup_hash_alg(const char *str, enum vb2_hash_algorithm *hash_alg)
+{
+	return lookup_helper(str, vb2_hash_names, VB2_HASH_ALG_COUNT, hash_alg);
+}
diff --git a/host/lib/include/host_common.h b/host/lib/include/host_common.h
index 43cb0250..55b15d3b 100644
--- a/host/lib/include/host_common.h
+++ b/host/lib/include/host_common.h
@@ -14,6 +14,7 @@
 #include "host_misc.h"
 #include "host_signature.h"
 #include "vboot_api.h"
+#include "vboot_host.h"
 #include "vboot_struct.h"
 
 /**
diff --git a/host/lib21/host_key.c b/host/lib21/host_key.c
index 6e3a2765..cfa99419 100644
--- a/host/lib21/host_key.c
+++ b/host/lib21/host_key.c
@@ -19,111 +19,6 @@
 #include "host_misc.h"
 #include "openssl_compat.h"
 
-const struct vb2_text_vs_enum vb2_text_vs_sig[] = {
-	{"RSA1024", VB2_SIG_RSA1024},
-	{"RSA2048", VB2_SIG_RSA2048},
-	{"RSA4096", VB2_SIG_RSA4096},
-	{"RSA8192", VB2_SIG_RSA8192},
-	{"RSA2048EXP3", VB2_SIG_RSA2048_EXP3},
-	{"RSA3072EXP3", VB2_SIG_RSA3072_EXP3},
-	{0, 0}
-};
-
-const struct vb2_text_vs_enum vb2_text_vs_hash[] = {
-	{"SHA1",   VB2_HASH_SHA1},
-	{"SHA256", VB2_HASH_SHA256},
-	{"SHA512", VB2_HASH_SHA512},
-	{0, 0}
-};
-
-const struct vb2_text_vs_enum vb2_text_vs_crypto[] = {
-	{"RSA1024 SHA1",   VB2_ALG_RSA1024_SHA1},
-	{"RSA1024 SHA256", VB2_ALG_RSA1024_SHA256},
-	{"RSA1024 SHA512", VB2_ALG_RSA1024_SHA512},
-	{"RSA2048 SHA1",   VB2_ALG_RSA2048_SHA1},
-	{"RSA2048 SHA256", VB2_ALG_RSA2048_SHA256},
-	{"RSA2048 SHA512", VB2_ALG_RSA2048_SHA512},
-	{"RSA4096 SHA1",   VB2_ALG_RSA4096_SHA1},
-	{"RSA4096 SHA256", VB2_ALG_RSA4096_SHA256},
-	{"RSA4096 SHA512", VB2_ALG_RSA4096_SHA512},
-	{"RSA8192 SHA1",   VB2_ALG_RSA8192_SHA1},
-	{"RSA8192 SHA256", VB2_ALG_RSA8192_SHA256},
-	{"RSA8192 SHA512", VB2_ALG_RSA8192_SHA512},
-	{"RSA2048 EXP3 SHA1",   VB2_ALG_RSA2048_EXP3_SHA1},
-	{"RSA2048 EXP3 SHA256", VB2_ALG_RSA2048_EXP3_SHA256},
-	{"RSA2048 EXP3 SHA512", VB2_ALG_RSA2048_EXP3_SHA512},
-	{"RSA3072 EXP3 SHA1",   VB2_ALG_RSA3072_EXP3_SHA1},
-	{"RSA3072 EXP3 SHA256", VB2_ALG_RSA3072_EXP3_SHA256},
-	{"RSA3072 EXP3 SHA512", VB2_ALG_RSA3072_EXP3_SHA512},
-	{0, 0}
-};
-
-const struct vb2_text_vs_enum vb2_file_vs_crypto[] = {
-	{"rsa1024", VB2_ALG_RSA1024_SHA1},
-	{"rsa1024", VB2_ALG_RSA1024_SHA256},
-	{"rsa1024", VB2_ALG_RSA1024_SHA512},
-	{"rsa2048", VB2_ALG_RSA2048_SHA1},
-	{"rsa2048", VB2_ALG_RSA2048_SHA256},
-	{"rsa2048", VB2_ALG_RSA2048_SHA512},
-	{"rsa4096", VB2_ALG_RSA4096_SHA1},
-	{"rsa4096", VB2_ALG_RSA4096_SHA256},
-	{"rsa4096", VB2_ALG_RSA4096_SHA512},
-	{"rsa8192", VB2_ALG_RSA8192_SHA1},
-	{"rsa8192", VB2_ALG_RSA8192_SHA256},
-	{"rsa8192", VB2_ALG_RSA8192_SHA512},
-	{"rsa2048_exp3", VB2_ALG_RSA2048_EXP3_SHA1},
-	{"rsa2048_exp3", VB2_ALG_RSA2048_EXP3_SHA256},
-	{"rsa2048_exp3", VB2_ALG_RSA2048_EXP3_SHA512},
-	{"rsa3072_exp3", VB2_ALG_RSA3072_EXP3_SHA1},
-	{"rsa3072_exp3", VB2_ALG_RSA3072_EXP3_SHA256},
-	{"rsa3072_exp3", VB2_ALG_RSA3072_EXP3_SHA512},
-	{0, 0}
-};
-
-const struct vb2_text_vs_enum *vb2_lookup_by_num(
-	const struct vb2_text_vs_enum *table,
-	const unsigned int num)
-{
-	for (; table->name; table++)
-		if (table->num == num)
-			return table;
-	return 0;
-}
-
-const struct vb2_text_vs_enum *vb2_lookup_by_name(
-	const struct vb2_text_vs_enum *table,
-	const char *name)
-{
-	for (; table->name; table++)
-		if (!strcasecmp(table->name, name))
-			return table;
-	return 0;
-}
-
-const char *vb2_get_sig_algorithm_name(enum vb2_signature_algorithm sig_alg)
-{
-	const struct vb2_text_vs_enum *entry =
-			vb2_lookup_by_num(vb2_text_vs_sig, sig_alg);
-
-	return entry ? entry->name : VB2_INVALID_ALG_NAME;
-}
-
-const char *vb2_get_crypto_algorithm_name(enum vb2_crypto_algorithm alg)
-{
-	const struct vb2_text_vs_enum *entry =
-			vb2_lookup_by_num(vb2_text_vs_crypto, alg);
-
-	return entry ? entry->name : VB2_INVALID_ALG_NAME;
-}
-
-const char *vb2_get_crypto_algorithm_file(enum vb2_crypto_algorithm alg)
-{
-	const struct vb2_text_vs_enum *entry =
-		vb2_lookup_by_num(vb2_file_vs_crypto, alg);
-
-	return entry ? entry->name : VB2_INVALID_ALG_NAME;
-}
-
 void vb2_private_key_free(struct vb2_private_key *key)
 {
 	if (!key)
diff --git a/host/lib21/include/host_key21.h b/host/lib21/include/host_key21.h
index 219e98ab..ae53ad5c 100644
--- a/host/lib21/include/host_key21.h
+++ b/host/lib21/include/host_key21.h
@@ -32,57 +32,6 @@ struct vb2_packed_private_key {
 	uint8_t key_data[0];
 };
 
-/* Convert between enums and human-readable form. Terminated with {0, 0}. */
-struct vb2_text_vs_enum {
-	const char *name;
-	unsigned int num;
-};
-
-/**
- * @param table         Table to search
- * @param num           Enum value to search for
- * @return pointer to table entry or NULL if no match
- */
-const struct vb2_text_vs_enum *vb2_lookup_by_num(
-	const struct vb2_text_vs_enum *table,
-	const unsigned int num);
-
-/**
- * @param table         Table to search
- * @param name          String value to search for
- * @return pointer to table entry or NULL if no match
- */
-const struct vb2_text_vs_enum *vb2_lookup_by_name(
-	const struct vb2_text_vs_enum *table,
-	const char *name);
-
-extern const struct vb2_text_vs_enum vb2_text_vs_sig[];
-extern const struct vb2_text_vs_enum vb2_text_vs_hash[];
-
-/**
- * Return the name of a signature algorithm.
- *
- * @param sig_alg	Signature algorithm to look up
- * @return The corresponding name, or VB2_INVALID_ALG_NAME if no match.
- */
-const char *vb2_get_sig_algorithm_name(enum vb2_signature_algorithm sig_alg);
-
-/**
- * Return the name of a crypto algorithm.
- *
- * @param alg		Crypto algorithm to look up
- * @return The corresponding name, or VB2_INVALID_ALG_NAME if no match.
- */
-const char *vb2_get_crypto_algorithm_name(enum vb2_crypto_algorithm alg);
-
-/**
- * Return the name of a crypto algorithm.
- *
- * @param alg		Crypto algorithm to look up
- * @return The corresponding stem filename, or VB2_INVALID_ALG_NAME if no match.
- */
-const char *vb2_get_crypto_algorithm_file(enum vb2_crypto_algorithm alg);
-
 /**
  * Free a private key.
  *