[PATCH v3 1/7] lib: uuid: add UUID v5 support

[Simon Glass]

Hi Caleb,

On Fri, 31 May 2024 at 07:50, Caleb Connolly <caleb.connolly at linaro.org> wrote:
>
> Add support for generating version 5 UUIDs, these are determistic and work

spelling

> 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.
>
> Tests for this are added in an upcoming patch.
>
> Signed-off-by: Caleb Connolly <caleb.connolly at linaro.org>
> ---
>  include/uuid.h | 17 +++++++++++++++++
>  lib/Kconfig    |  8 ++++++++
>  lib/uuid.c     | 37 +++++++++++++++++++++++++++++++++++++
>  3 files changed, 62 insertions(+)
>
> diff --git a/include/uuid.h b/include/uuid.h
> index f5a941250f48..539affaa47b9 100644
> --- a/include/uuid.h
> +++ b/include/uuid.h
> @@ -10,8 +10,9 @@
>  #ifndef __UUID_H__
>  #define __UUID_H__
>
>  #include <linux/bitops.h>
> +#include <linux/kconfig.h>
>
>  /*
>   * UUID - Universally Unique IDentifier - 128 bits unique number.
>   *        There are 5 versions and one variant of UUID defined by RFC4122
> @@ -142,8 +143,24 @@ void gen_rand_uuid(unsigned char *uuid_bin);
>   * @param          - uuid output type: UUID - 0, GUID - 1
>   */
>  void gen_rand_uuid_str(char *uuid_str, int str_format);
>
> +#if IS_ENABLED(CONFIG_UUID_GEN_V5)
> +/**
> + * gen_uuid_v5() - generate UUID v5 from namespace and other seed data.
> + *
> + * @namespace:   pointer to UUID namespace salt
> + * @uuid:        pointer to allocated UUID output
> + * @...:         NULL terminated list of seed data as pairs of pointers
> + *               to data and their lengths
> + */
> +void gen_uuid_v5(const struct uuid *namespace, struct uuid *uuid, ...);
> +#else
> +static inline void gen_uuid_v5(const struct uuid *namespace, struct uuid *uuid, ...)
> +{
> +}
> +#endif

Can you explain somewhere why the static inline is needed?

> +
>  /**
>   * uuid_str_to_le_bin() - Convert string UUID to little endian binary data.
>   * @uuid_str:  pointer to UUID string
>   * @uuid_bin:  pointer to allocated array for little endian output [16B]
> diff --git a/lib/Kconfig b/lib/Kconfig
> index 189e6eb31aa1..2941532f25cf 100644
> --- a/lib/Kconfig
> +++ b/lib/Kconfig
> @@ -80,8 +80,16 @@ config RANDOM_UUID
>         help
>           Enable the generation of partitions with random UUIDs if none
>           are provided.
>
> +config UUID_GEN_V5
> +       bool "Enable UUID version 5 generation"
> +       select LIB_UUID
> +       depends on SHA1
> +       help
> +         Enable the generation of version 5 UUIDs, these are determistic and

spelling

> +         generated from a namespace UUID, and a string (such as a board name).
> +
>  config SPL_LIB_UUID
>         depends on SPL
>         bool
>
> diff --git a/lib/uuid.c b/lib/uuid.c
> index dfa2320ba267..2df0523e717f 100644
> --- a/lib/uuid.c
> +++ b/lib/uuid.c
> @@ -21,8 +21,9 @@
>  #include <part_efi.h>
>  #include <malloc.h>
>  #include <dm/uclass.h>
>  #include <rng.h>
> +#include <u-boot/sha1.h>
>
>  int uuid_str_valid(const char *uuid)
>  {
>         int i, valid;
> @@ -368,8 +369,44 @@ void uuid_bin_to_str(const unsigned char *uuid_bin, char *uuid_str,
>                 }
>         }
>  }
>
> +#if IS_ENABLED(CONFIG_UUID_GEN_V5)
> +void gen_uuid_v5(const struct uuid *namespace, struct uuid *uuid, ...)
> +{
> +       sha1_context ctx;
> +       va_list args;
> +       const uint8_t *data;
> +       uint8_t hash[SHA1_SUM_LEN];
> +       uint32_t tmp;
> +
> +       sha1_starts(&ctx);
> +       /* Hash the namespace UUID as salt */
> +       sha1_update(&ctx, (unsigned char *)namespace, UUID_BIN_LEN);
> +       va_start(args, uuid);
> +
> +       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(uuid, hash, sizeof(*uuid));
> +
> +       /* Configure variant/version bits */
> +       tmp = be32_to_cpu(uuid->time_hi_and_version);
> +       tmp = (tmp & ~UUID_VERSION_MASK) | (5 << UUID_VERSION_SHIFT);
> +       uuid->time_hi_and_version = cpu_to_be32(tmp);
> +
> +       uuid->clock_seq_hi_and_reserved &= UUID_VARIANT_MASK;
> +       uuid->clock_seq_hi_and_reserved |= UUID_VARIANT << UUID_VARIANT_SHIFT;
> +}
> +#endif
> +
>  #if defined(CONFIG_RANDOM_UUID) || defined(CONFIG_CMD_UUID)
>  void gen_rand_uuid(unsigned char *uuid_bin)
>  {
>         u32 ptr[4];
>
> --
> 2.45.0
>

Regards,
Simon