lib: uuid: add UUID v5 support

Add support for generating version 5 UUIDs, these are determistic and work
by hashing a "namespace" UUID together with some unique data. One intended
usecase is to allow for dynamically generate payload UUIDs for UEFI
capsule updates, so that supported boards can have their own UUIDs
without needing to hardcode them.

In addition, move the common bit twiddling code from gen_ran_uuid into a
separate function and rewrite it not to use clrsetbits (which is not
available when building as part of host tools).

Tests for this are added in an upcoming patch.

Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>

1 files changed, 52 insertions, 7 deletions

diff --git a/lib/uuid.c b/lib/uuid.c
index dfa2320ba26..c9dfdf007a1 100644
--- a/lib/uuid.c
+++ b/lib/uuid.c
@@ -22,6 +22,7 @@
 #include <malloc.h>
 #include <dm/uclass.h>
 #include <rng.h>
+#include <u-boot/sha1.h>
 
 int uuid_str_valid(const char *uuid)
 {
@@ -369,6 +370,56 @@ void uuid_bin_to_str(const unsigned char *uuid_bin, char *uuid_str,
 	}
 }
 
+static void configure_uuid(struct uuid *uuid, unsigned char version)
+{
+	uint16_t tmp;
+
+	/* Configure variant/version bits */
+	tmp = be16_to_cpu(uuid->time_hi_and_version);
+	tmp = (tmp & ~UUID_VERSION_MASK) | (version << UUID_VERSION_SHIFT);
+	uuid->time_hi_and_version = cpu_to_be16(tmp);
+
+	uuid->clock_seq_hi_and_reserved &= ~UUID_VARIANT_MASK;
+	uuid->clock_seq_hi_and_reserved |= (UUID_VARIANT << UUID_VARIANT_SHIFT);
+}
+
+void gen_v5_guid(const struct uuid *namespace, struct efi_guid *guid, ...)
+{
+	sha1_context ctx;
+	va_list args;
+	const uint8_t *data;
+	uint32_t *tmp32;
+	uint16_t *tmp16;
+	uint8_t hash[SHA1_SUM_LEN];
+
+	sha1_starts(&ctx);
+	/* Hash the namespace UUID as salt */
+	sha1_update(&ctx, (unsigned char *)namespace, UUID_BIN_LEN);
+	va_start(args, guid);
+
+	while ((data = va_arg(args, const uint8_t *))) {
+		unsigned int len = va_arg(args, size_t);
+
+		sha1_update(&ctx, data, len);
+	}
+
+	va_end(args);
+	sha1_finish(&ctx, hash);
+
+	/* Truncate the hash into output UUID, it is already big endian */
+	memcpy(guid, hash, sizeof(*guid));
+
+	configure_uuid((struct uuid *)guid, 5);
+
+	/* Make little endian */
+	tmp32 = (uint32_t *)&guid->b[0];
+	*tmp32 = cpu_to_le32(be32_to_cpu(*tmp32));
+	tmp16 = (uint16_t *)&guid->b[4];
+	*tmp16 = cpu_to_le16(be16_to_cpu(*tmp16));
+	tmp16 = (uint16_t *)&guid->b[6];
+	*tmp16 = cpu_to_le16(be16_to_cpu(*tmp16));
+}
+
 #if defined(CONFIG_RANDOM_UUID) || defined(CONFIG_CMD_UUID)
 void gen_rand_uuid(unsigned char *uuid_bin)
 {
@@ -395,13 +446,7 @@ void gen_rand_uuid(unsigned char *uuid_bin)
 	for (i = 0; i < 4; i++)
 		ptr[i] = rand();
 
-	clrsetbits_be16(&uuid->time_hi_and_version,
-			UUID_VERSION_MASK,
-			UUID_VERSION << UUID_VERSION_SHIFT);
-
-	clrsetbits_8(&uuid->clock_seq_hi_and_reserved,
-		     UUID_VARIANT_MASK,
-		     UUID_VARIANT << UUID_VARIANT_SHIFT);
+	configure_uuid(uuid, UUID_VERSION);
 
 	memcpy(uuid_bin, uuid, 16);
 }