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      1 /* SPDX-License-Identifier: GPL-2.0+ */
      2 /*
      3  * Copyright (c) 2012 The Chromium OS Authors.
      4  */
      5 
      6 #ifndef _HASH_H
      7 #define _HASH_H
      8 
      9 /*
     10  * Maximum digest size for all algorithms we support. Having this value
     11  * avoids a malloc() or C99 local declaration in common/cmd_hash.c.
     12  */
     13 #define HASH_MAX_DIGEST_SIZE	32
     14 
     15 enum {
     16 	HASH_FLAG_VERIFY	= 1 << 0,	/* Enable verify mode */
     17 	HASH_FLAG_ENV		= 1 << 1,	/* Allow env vars */
     18 };
     19 
     20 struct hash_algo {
     21 	const char *name;			/* Name of algorithm */
     22 	int digest_size;			/* Length of digest */
     23 	/**
     24 	 * hash_func_ws: Generic hashing function
     25 	 *
     26 	 * This is the generic prototype for a hashing function. We only
     27 	 * have the watchdog version at present.
     28 	 *
     29 	 * @input:	Input buffer
     30 	 * @ilen:	Input buffer length
     31 	 * @output:	Checksum result (length depends on algorithm)
     32 	 * @chunk_sz:	Trigger watchdog after processing this many bytes
     33 	 */
     34 	void (*hash_func_ws)(const unsigned char *input, unsigned int ilen,
     35 		unsigned char *output, unsigned int chunk_sz);
     36 	int chunk_size;				/* Watchdog chunk size */
     37 	/*
     38 	 * hash_init: Create the context for progressive hashing
     39 	 *
     40 	 * @algo: Pointer to the hash_algo struct
     41 	 * @ctxp: Pointer to the pointer of the context for hashing
     42 	 * @return 0 if ok, -1 on error
     43 	 */
     44 	int (*hash_init)(struct hash_algo *algo, void **ctxp);
     45 	/*
     46 	 * hash_update: Perform hashing on the given buffer
     47 	 *
     48 	 * The context is freed by this function if an error occurs.
     49 	 *
     50 	 * @algo: Pointer to the hash_algo struct
     51 	 * @ctx: Pointer to the context for hashing
     52 	 * @buf: Pointer to the buffer being hashed
     53 	 * @size: Size of the buffer being hashed
     54 	 * @is_last: 1 if this is the last update; 0 otherwise
     55 	 * @return 0 if ok, -1 on error
     56 	 */
     57 	int (*hash_update)(struct hash_algo *algo, void *ctx, const void *buf,
     58 			   unsigned int size, int is_last);
     59 	/*
     60 	 * hash_finish: Write the hash result to the given buffer
     61 	 *
     62 	 * The context is freed by this function.
     63 	 *
     64 	 * @algo: Pointer to the hash_algo struct
     65 	 * @ctx: Pointer to the context for hashing
     66 	 * @dest_buf: Pointer to the buffer for the result
     67 	 * @size: Size of the buffer for the result
     68 	 * @return 0 if ok, -ENOSPC if size of the result buffer is too small
     69 	 *   or -1 on other errors
     70 	 */
     71 	int (*hash_finish)(struct hash_algo *algo, void *ctx, void *dest_buf,
     72 			   int size);
     73 };
     74 
     75 #ifndef USE_HOSTCC
     76 /**
     77  * hash_command: Process a hash command for a particular algorithm
     78  *
     79  * This common function is used to implement specific hash commands.
     80  *
     81  * @algo_name:		Hash algorithm being used (lower case!)
     82  * @flags:		Flags value (HASH_FLAG_...)
     83  * @cmdtp:		Pointer to command table entry
     84  * @flag:		Some flags normally 0 (see CMD_FLAG_.. above)
     85  * @argc:		Number of arguments (arg 0 must be the command text)
     86  * @argv:		Arguments
     87  */
     88 int hash_command(const char *algo_name, int flags, cmd_tbl_t *cmdtp, int flag,
     89 		 int argc, char * const argv[]);
     90 
     91 /**
     92  * hash_block() - Hash a block according to the requested algorithm
     93  *
     94  * The caller probably knows the hash length for the chosen algorithm, but
     95  * in order to provide a general interface, and output_size parameter is
     96  * provided.
     97  *
     98  * @algo_name:		Hash algorithm to use
     99  * @data:		Data to hash
    100  * @len:		Lengh of data to hash in bytes
    101  * @output:		Place to put hash value
    102  * @output_size:	On entry, pointer to the number of bytes available in
    103  *			output. On exit, pointer to the number of bytes used.
    104  *			If NULL, then it is assumed that the caller has
    105  *			allocated enough space for the hash. This is possible
    106  *			since the caller is selecting the algorithm.
    107  * @return 0 if ok, -ve on error: -EPROTONOSUPPORT for an unknown algorithm,
    108  * -ENOSPC if the output buffer is not large enough.
    109  */
    110 int hash_block(const char *algo_name, const void *data, unsigned int len,
    111 	       uint8_t *output, int *output_size);
    112 
    113 #endif /* !USE_HOSTCC */
    114 
    115 /**
    116  * hash_lookup_algo() - Look up the hash_algo struct for an algorithm
    117  *
    118  * The function returns the pointer to the struct or -EPROTONOSUPPORT if the
    119  * algorithm is not available.
    120  *
    121  * @algo_name: Hash algorithm to look up
    122  * @algop: Pointer to the hash_algo struct if found
    123  *
    124  * @return 0 if ok, -EPROTONOSUPPORT for an unknown algorithm.
    125  */
    126 int hash_lookup_algo(const char *algo_name, struct hash_algo **algop);
    127 
    128 /**
    129  * hash_progressive_lookup_algo() - Look up hash_algo for prog. hash support
    130  *
    131  * The function returns the pointer to the struct or -EPROTONOSUPPORT if the
    132  * algorithm is not available with progressive hash support.
    133  *
    134  * @algo_name: Hash algorithm to look up
    135  * @algop: Pointer to the hash_algo struct if found
    136  *
    137  * @return 0 if ok, -EPROTONOSUPPORT for an unknown algorithm.
    138  */
    139 int hash_progressive_lookup_algo(const char *algo_name,
    140 				 struct hash_algo **algop);
    141 
    142 /**
    143  * hash_parse_string() - Parse hash string into a binary array
    144  *
    145  * The function parses a hash string into a binary array that
    146  * can for example easily be used to compare to hash values.
    147  *
    148  * @algo_name: Hash algorithm to look up
    149  * @str: Hash string to get parsed
    150  * @result: Binary array of the parsed hash string
    151  *
    152  * @return 0 if ok, -EPROTONOSUPPORT for an unknown algorithm.
    153  */
    154 int hash_parse_string(const char *algo_name, const char *str, uint8_t *result);
    155 
    156 #endif
    157