include/hash.h

   1 /*
   2  * Copyright (c) 2012 The Chromium OS Authors.
   3  * SPDX-License-Identifier:     GPL-2.0+
   4  */
   5
   6 #ifndef _HASH_H
   7 #define _HASH_H
   8
   9 #if defined(CONFIG_SHA1SUM_VERIFY) || defined(CONFIG_CRC32_VERIFY)
  10 #define CONFIG_HASH_VERIFY
  11 #endif
  12
  13 struct hash_algo {
  14         const char *name;                       /* Name of algorithm */
  15         int digest_size;                        /* Length of digest */
  16         /**
  17          * hash_func_ws: Generic hashing function
  18          *
  19          * This is the generic prototype for a hashing function. We only
  20          * have the watchdog version at present.
  21          *
  22          * @input:      Input buffer
  23          * @ilen:       Input buffer length
  24          * @output:     Checksum result (length depends on algorithm)
  25          * @chunk_sz:   Trigger watchdog after processing this many bytes
  26          */
  27         void (*hash_func_ws)(const unsigned char *input, unsigned int ilen,
  28                 unsigned char *output, unsigned int chunk_sz);
  29         int chunk_size;                         /* Watchdog chunk size */
  30         /*
  31          * hash_init: Create the context for progressive hashing
  32          *
  33          * @algo: Pointer to the hash_algo struct
  34          * @ctxp: Pointer to the pointer of the context for hashing
  35          * @return 0 if ok, -1 on error
  36          */
  37         int (*hash_init)(struct hash_algo *algo, void **ctxp);
  38         /*
  39          * hash_update: Perform hashing on the given buffer
  40          *
  41          * The context is freed by this function if an error occurs.
  42          *
  43          * @algo: Pointer to the hash_algo struct
  44          * @ctx: Pointer to the context for hashing
  45          * @buf: Pointer to the buffer being hashed
  46          * @size: Size of the buffer being hashed
  47          * @is_last: 1 if this is the last update; 0 otherwise
  48          * @return 0 if ok, -1 on error
  49          */
  50         int (*hash_update)(struct hash_algo *algo, void *ctx, const void *buf,
  51                            unsigned int size, int is_last);
  52         /*
  53          * hash_finish: Write the hash result to the given buffer
  54          *
  55          * The context is freed by this function.
  56          *
  57          * @algo: Pointer to the hash_algo struct
  58          * @ctx: Pointer to the context for hashing
  59          * @dest_buf: Pointer to the buffer for the result
  60          * @size: Size of the buffer for the result
  61          * @return 0 if ok, -ENOSPC if size of the result buffer is too small
  62          *   or -1 on other errors
  63          */
  64         int (*hash_finish)(struct hash_algo *algo, void *ctx, void *dest_buf,
  65                            int size);
  66 };
  67
  68 /*
  69  * Maximum digest size for all algorithms we support. Having this value
  70  * avoids a malloc() or C99 local declaration in common/cmd_hash.c.
  71  */
  72 #define HASH_MAX_DIGEST_SIZE    32
  73
  74 enum {
  75         HASH_FLAG_VERIFY        = 1 << 0,       /* Enable verify mode */
  76         HASH_FLAG_ENV           = 1 << 1,       /* Allow env vars */
  77 };
  78
  79 /**
  80  * hash_command: Process a hash command for a particular algorithm
  81  *
  82  * This common function is used to implement specific hash commands.
  83  *
  84  * @algo_name:          Hash algorithm being used (lower case!)
  85  * @flags:              Flags value (HASH_FLAG_...)
  86  * @cmdtp:              Pointer to command table entry
  87  * @flag:               Some flags normally 0 (see CMD_FLAG_.. above)
  88  * @argc:               Number of arguments (arg 0 must be the command text)
  89  * @argv:               Arguments
  90  */
  91 int hash_command(const char *algo_name, int flags, cmd_tbl_t *cmdtp, int flag,
  92                  int argc, char * const argv[]);
  93
  94 /**
  95  * hash_block() - Hash a block according to the requested algorithm
  96  *
  97  * The caller probably knows the hash length for the chosen algorithm, but
  98  * in order to provide a general interface, and output_size parameter is
  99  * provided.
 100  *
 101  * @algo_name:          Hash algorithm to use
 102  * @data:               Data to hash
 103  * @len:                Lengh of data to hash in bytes
 104  * @output:             Place to put hash value
 105  * @output_size:        On entry, pointer to the number of bytes available in
 106  *                      output. On exit, pointer to the number of bytes used.
 107  *                      If NULL, then it is assumed that the caller has
 108  *                      allocated enough space for the hash. This is possible
 109  *                      since the caller is selecting the algorithm.
 110  * @return 0 if ok, -ve on error: -EPROTONOSUPPORT for an unknown algorithm,
 111  * -ENOSPC if the output buffer is not large enough.
 112  */
 113 int hash_block(const char *algo_name, const void *data, unsigned int len,
 114                uint8_t *output, int *output_size);
 115
 116 /**
 117  * hash_lookup_algo() - Look up the hash_algo struct for an algorithm
 118  *
 119  * The function returns the pointer to the struct or -EPROTONOSUPPORT if the
 120  * algorithm is not available.
 121  *
 122  * @algo_name: Hash algorithm to look up
 123  * @algop: Pointer to the hash_algo struct if found
 124  *
 125  * @return 0 if ok, -EPROTONOSUPPORT for an unknown algorithm.
 126  */
 127 int hash_lookup_algo(const char *algo_name, struct hash_algo **algop);
 128 #endif