[U-Boot,v2,10/23] Add generic hash API

We have a SHA1 command and want to add a SHA256 command also. Instead of
duplicating the code, create a generic hash API which can process
commands for different algorithms.

Signed-off-by: Simon Glass <sjg@chromium.org>
---
Changes in v2:
- Add generic hash API to allow SHA256 command to be added without duplication

 common/Makefile |    1 +
 common/hash.c   |  221 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 include/hash.h  |   69 +++++++++++++++++
 3 files changed, 291 insertions(+), 0 deletions(-)
 create mode 100644 common/hash.c
 create mode 100644 include/hash.h

Hi Simon,

On Thu, Nov 22, 2012 at 1:12 PM, Simon Glass <sjg@chromium.org> wrote:
> We have a SHA1 command and want to add a SHA256 command also. Instead of
> duplicating the code, create a generic hash API which can process
> commands for different algorithms.
>
> Signed-off-by: Simon Glass <sjg@chromium.org>
> ---
> Changes in v2:
> - Add generic hash API to allow SHA256 command to be added without duplication
>
>  common/Makefile |    1 +
>  common/hash.c   |  221 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  include/hash.h  |   69 +++++++++++++++++
>  3 files changed, 291 insertions(+), 0 deletions(-)
>  create mode 100644 common/hash.c
>  create mode 100644 include/hash.h
>
> diff --git a/common/Makefile b/common/Makefile
> index 84968f8..eb175c1 100644
> --- a/common/Makefile
> +++ b/common/Makefile
> @@ -31,6 +31,7 @@ COBJS-y += main.o
>  COBJS-y += command.o
>  COBJS-y += exports.o
>  COBJS-$(CONFIG_SYS_HUSH_PARSER) += hush.o
> +COBJS-y += hash.o

Why not put them in alphabetical order?

>  COBJS-y += s_record.o
>  COBJS-y += xyzModem.o
>  COBJS-y += cmd_disk.o
> diff --git a/common/hash.c b/common/hash.c
> new file mode 100644
> index 0000000..9a844b8
> --- /dev/null
> +++ b/common/hash.c
> @@ -0,0 +1,221 @@
> +/*
> + * Copyright (c) 2012 The Chromium OS Authors.
> + *
> + * (C) Copyright 2011
> + * Joe Hershberger, National Instruments, joe.hershberger@ni.com
> + *
> + * (C) Copyright 2000
> + * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
> + * MA 02111-1307 USA
> + */
> +
> +#include <common.h>
> +#include <command.h>
> +#include <hash.h>
> +#include <sha1.h>
> +#include <sha256.h>
> +
> +/*
> + * These are the hash algorithms we support. Chips which support accelerated
> + * crypto could perhaps add named version of these algorithms here.
> + */
> +static struct hash_algo hash_algo[] = {
> +#ifdef CONFIG_SHA1
> +       {
> +               "SHA1",
> +               SHA1_SUM_LEN,
> +               sha1_csum_wd,
> +               CHUNKSZ_SHA1,
> +       },
> +#endif
> +#ifdef CONFIG_SHA256
> +       {
> +               "SHA256",
> +               SHA256_SUM_LEN,
> +               sha256_csum_wd,
> +               CHUNKSZ_SHA256,
> +       },
> +#endif
> +};
> +
> +/**
> + * store_result: Store the resulting sum to an address or variable
> + *
> + * @algo:              Hash algorithm being used
> + * @sum:               Hash digest (algo->digest_size bytes)
> + * @dest:              Destination, interpreted as a hex address if it starts
> + *                     with * or otherwise as an environment variable.
> + */
> +static void store_result(struct hash_algo *algo, const u8 *sum,
> +                        const char *dest)
> +{
> +       unsigned int i;
> +
> +       if (*dest == '*') {
> +               u8 *ptr;
> +
> +               ptr = (u8 *)simple_strtoul(dest + 1, NULL, 16);
> +               memcpy(ptr, sum, algo->digest_size);
> +       } else {
> +               char str_output[HASH_MAX_DIGEST_SIZE * 2 + 1];
> +               char *str_ptr = str_output;
> +
> +               for (i = 0; i < algo->digest_size; i++) {
> +                       sprintf(str_ptr, "%02x", sum[i]);
> +                       str_ptr += 2;
> +               }
> +               str_ptr = '\0';
> +               setenv(dest, str_output);
> +       }
> +}
> +
> +/**
> + * parse_verify_sum: Parse a hash verification parameter
> + *
> + * @algo:              Hash algorithm being used
> + * @verify_str:                Argument to parse. If it starts with * then it is
> + *                     interpreted as a hex address containing the hash.
> + *                     If the length is exactly the right number of hex digits
> + *                     for the digest size, then we assume it is a hex digest.
> + *                     Otherwise we assume it is an environment variable, and
> + *                     look up its value (it must contain a hex digest).
> + * @vsum:              Returns binary digest value (algo->digest_size bytes)
> + * @return 0 if ok, non-zero on error
> + */
> +static int parse_verify_sum(struct hash_algo *algo, char *verify_str, u8 *vsum)
> +{
> +       if (*verify_str == '*') {
> +               u8 *ptr;
> +
> +               ptr = (u8 *)simple_strtoul(verify_str + 1, NULL, 16);
> +               memcpy(vsum, ptr, algo->digest_size);
> +       } else {
> +               unsigned int i;
> +               char *vsum_str;
> +               int digits = algo->digest_size * 2;
> +
> +               /*
> +                * As with the original code from sha1sum.c, we assume that a
> +                * string which matches the digest size exactly is a hex
> +                * string and not an environment variable.
> +                */
> +               if (strlen(verify_str) == digits)
> +                       vsum_str = verify_str;
> +               else {
> +                       vsum_str = getenv(verify_str);
> +                       if (vsum_str == NULL || strlen(vsum_str) != digits) {
> +                               printf("Expected %d hex digits in env var\n",
> +                                      digits);
> +                               return 1;
> +                       }
> +               }
> +
> +               for (i = 0; i < algo->digest_size; i++) {
> +                       char *nullp = vsum_str + (i + 1) * 2;
> +                       char end = *nullp;
> +
> +                       *nullp = '\0';
> +                       vsum[i] = simple_strtoul(vsum_str + (i * 2), NULL, 16);
> +                       *nullp = end;
> +               }
> +       }
> +       return 0;
> +}
> +
> +static struct hash_algo *find_hash_algo(const char *name)
> +{
> +       int i;
> +
> +       for (i = 0; i < ARRAY_SIZE(hash_algo); i++) {
> +               if (!stricmp(name, hash_algo[i].name))
> +                       return &hash_algo[i];
> +       }
> +
> +       return NULL;
> +}
> +
> +static void show_hash(struct hash_algo *algo, ulong addr, ulong len,
> +                     u8 *output)
> +{
> +       int i;
> +
> +       printf("%s for %08lx ... %08lx ==> ", algo->name, addr, addr + len - 1);
> +       for (i = 0; i < algo->digest_size; i++)
> +               printf("%02x", output[i]);
> +}
> +
> +int hash_command(const char *algo_name, int verify, cmd_tbl_t *cmdtp, int flag,
> +                int argc, char * const argv[])
> +{
> +       struct hash_algo *algo;
> +       ulong addr, len;
> +       u8 output[HASH_MAX_DIGEST_SIZE];
> +       u8 vsum[HASH_MAX_DIGEST_SIZE];
> +
> +       if (argc < 2)
> +               return CMD_RET_USAGE;
> +
> +       algo = find_hash_algo(algo_name);
> +       if (!algo) {
> +               printf("Unknown hash algorithm '%s'\n", algo_name);
> +               return CMD_RET_USAGE;
> +       }
> +       addr = simple_strtoul(*argv++, NULL, 16);
> +       len = simple_strtoul(*argv++, NULL, 16);
> +       argc -= 2;
> +
> +       if (algo->digest_size > HASH_MAX_DIGEST_SIZE) {
> +               puts("HASH_MAX_DIGEST_SIZE exceeded\n");
> +               return 1;
> +       }
> +
> +       algo->hash_func_ws((const unsigned char *)addr, len, output,
> +                          algo->chunk_size);
> +
> +       /* Try to avoid code bloat when verify is not needed */
> +#ifdef CONFIG_HASH_VERIFY
> +       if (verify) {
> +#else
> +       if (0) {
> +#endif
> +               if (!argc)
> +                       return CMD_RET_USAGE;
> +               if (parse_verify_sum(algo, *argv, vsum)) {
> +                       printf("ERROR: %s does not contain a valid SHA1 sum\n",
> +                               *argv);

You should probably use the name of the algo in the error message, not
a fixed SHA1.

> +                       return 1;
> +               }
> +               if (memcmp(output, vsum, algo->digest_size) != 0) {
> +                       int i;
> +
> +                       show_hash(algo, addr, len, output);
> +                       printf(" != ");
> +                       for (i = 0; i < algo->digest_size; i++)
> +                               printf("%02x", vsum[i]);
> +                       puts(" ** ERROR **\n");
> +                       return 1;
> +               }
> +       } else {
> +               show_hash(algo, addr, len, output);
> +               printf("\n");
> +
> +               if (argc)
> +                       store_result(algo, output, *argv);
> +       }
> +
> +       return 0;
> +}
> diff --git a/include/hash.h b/include/hash.h
> new file mode 100644
> index 0000000..34ba558
> --- /dev/null
> +++ b/include/hash.h
> @@ -0,0 +1,69 @@
> +/*
> + * Copyright (c) 2012 The Chromium OS Authors.
> + * See file CREDITS for list of people who contributed to this
> + * project.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
> + * MA 02111-1307 USA
> + */
> +
> +#ifndef _HASH_H
> +#define _HASH_H
> +
> +#ifdef CONFIG_SHA1SUM_VERIFY
> +#define CONFIG_HASH_VERIFY
> +#endif
> +
> +struct hash_algo {
> +       const char *name;                       /* Name of algorithm */
> +       int digest_size;                        /* Length of digest */
> +       /**
> +        * hash_func_ws: Generic hashing function
> +        *
> +        * This is the generic prototype for a hashing function. We only
> +        * have the watchdog version at present.
> +        *
> +        * @input:      Input buffer
> +        * @ilen:       Input buffer length
> +        * @output:     Checksum result (length depends on algorithm)
> +        * @chunk_sz:   Trigger watchdog after processing this many bytes
> +        */
> +       void (*hash_func_ws)(const unsigned char *input, unsigned int ilen,
> +               unsigned char *output, unsigned int chunk_sz);
> +       int chunk_size;                         /* Watchdog chunk size */
> +};
> +
> +/*
> + * Maximum digest size for all algorithms we support. Having this value
> + * avoids a malloc() or C99 local declaration in common/cmd_hash.c.
> + */
> +#define HASH_MAX_DIGEST_SIZE   32
> +
> +/**
> + * hash_command: Process a hash command for a particular algorithm
> + *
> + * This common function is used to implement specific hash commands.
> + *
> + * @algo_name:         Hash algorithm being used
> + * @verify:            Non-zero to enable verify mode
> + * @cmdtp:             Pointer to command table entry
> + * @flag:              Some flags normally 0 (see CMD_FLAG_.. above)
> + * @argc:              Number of arguments (arg 0 must be the command text)
> + * @argv:              Arguments
> + */
> +int hash_command(const char *algo_name, int verify, cmd_tbl_t *cmdtp, int flag,
> +                int argc, char * const argv[]);
> +
> +#endif

Otherwise, looks good.

-Joe