From 4c5e1ff31bf3d816412232ed7b4a2a581a50b262 Mon Sep 17 00:00:00 2001 From: Caleb Connolly Date: Fri, 30 Aug 2024 13:34:32 +0100 Subject: 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 Signed-off-by: Caleb Connolly --- lib/Kconfig | 1 + lib/uuid.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++------- 2 files changed, 53 insertions(+), 7 deletions(-) (limited to 'lib') diff --git a/lib/Kconfig b/lib/Kconfig index 86919410cd7..1dd4f271595 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -73,6 +73,7 @@ config HAVE_PRIVATE_LIBGCC config LIB_UUID bool + select SHA1 config RANDOM_UUID bool "GPT Random UUID generation" 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 #include #include +#include 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); } -- cgit v1.3.1