cryptohashfuncs.c

Go to the documentation of this file.

/*-------------------------------------------------------------------------
 *
 * cryptohashfuncs.c
 *    Cryptographic hash functions
 *
 * Portions Copyright (c) 2018-2024, PostgreSQL Global Development Group
 *
 *
 * IDENTIFICATION
 *    src/backend/utils/adt/cryptohashfuncs.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"
 
#include "common/cryptohash.h"
#include "common/md5.h"
#include "common/sha2.h"
#include "utils/builtins.h"
#include "varatt.h"
 
 
/*
 * MD5
 */
 
/* MD5 produces a 16 byte (128 bit) hash; double it for hex */
#define MD5_HASH_LEN  32
 
/*
 * Create an MD5 hash of a text value and return it as hex string.
 */
Datum
md5_text(PG_FUNCTION_ARGS)
{
    text       *in_text = PG_GETARG_TEXT_PP(0);
    size_t      len;
    char        hexsum[MD5_HASH_LEN + 1];
    const char *errstr = NULL;
 
    /* Calculate the length of the buffer using varlena metadata */
    len = VARSIZE_ANY_EXHDR(in_text);
 
    /* get the hash result */
    if (pg_md5_hash(VARDATA_ANY(in_text), len, hexsum, &errstr) == false)
        ereport(ERROR,
                (errcode(ERRCODE_INTERNAL_ERROR),
                 errmsg("could not compute %s hash: %s", "MD5",
                        errstr)));
 
    /* convert to text and return it */
    PG_RETURN_TEXT_P(cstring_to_text(hexsum));
}
 
/*
 * Create an MD5 hash of a bytea value and return it as a hex string.
 */
Datum
md5_bytea(PG_FUNCTION_ARGS)
{
    bytea      *in = PG_GETARG_BYTEA_PP(0);
    size_t      len;
    char        hexsum[MD5_HASH_LEN + 1];
    const char *errstr = NULL;
 
    len = VARSIZE_ANY_EXHDR(in);
    if (pg_md5_hash(VARDATA_ANY(in), len, hexsum, &errstr) == false)
        ereport(ERROR,
                (errcode(ERRCODE_INTERNAL_ERROR),
                 errmsg("could not compute %s hash: %s", "MD5",
                        errstr)));
 
    PG_RETURN_TEXT_P(cstring_to_text(hexsum));
}
 
/*
 * Internal routine to compute a cryptohash with the given bytea input.
 */
static inline bytea *
cryptohash_internal(pg_cryptohash_type type, bytea *input)
{
    const uint8 *data;
    const char *typestr = NULL;
    int         digest_len = 0;
    size_t      len;
    pg_cryptohash_ctx *ctx;
    bytea      *result;
 
    switch (type)
    {
        case PG_SHA224:
            typestr = "SHA224";
            digest_len = PG_SHA224_DIGEST_LENGTH;
            break;
        case PG_SHA256:
            typestr = "SHA256";
            digest_len = PG_SHA256_DIGEST_LENGTH;
            break;
        case PG_SHA384:
            typestr = "SHA384";
            digest_len = PG_SHA384_DIGEST_LENGTH;
            break;
        case PG_SHA512:
            typestr = "SHA512";
            digest_len = PG_SHA512_DIGEST_LENGTH;
            break;
        case PG_MD5:
        case PG_SHA1:
            elog(ERROR, "unsupported cryptohash type %d", type);
            break;
    }
 
    result = palloc0(digest_len + VARHDRSZ);
    len = VARSIZE_ANY_EXHDR(input);
    data = (unsigned char *) VARDATA_ANY(input);
 
    ctx = pg_cryptohash_create(type);
    if (pg_cryptohash_init(ctx) < 0)
        elog(ERROR, "could not initialize %s context: %s", typestr,
             pg_cryptohash_error(ctx));
    if (pg_cryptohash_update(ctx, data, len) < 0)
        elog(ERROR, "could not update %s context: %s", typestr,
             pg_cryptohash_error(ctx));
    if (pg_cryptohash_final(ctx, (unsigned char *) VARDATA(result),
                            digest_len) < 0)
        elog(ERROR, "could not finalize %s context: %s", typestr,
             pg_cryptohash_error(ctx));
    pg_cryptohash_free(ctx);
 
    SET_VARSIZE(result, digest_len + VARHDRSZ);
 
    return result;
}
 
/*
 * SHA-2 variants
 */
 
Datum
sha224_bytea(PG_FUNCTION_ARGS)
{
    bytea      *result = cryptohash_internal(PG_SHA224, PG_GETARG_BYTEA_PP(0));
 
    PG_RETURN_BYTEA_P(result);
}
 
Datum
sha256_bytea(PG_FUNCTION_ARGS)
{
    bytea      *result = cryptohash_internal(PG_SHA256, PG_GETARG_BYTEA_PP(0));
 
    PG_RETURN_BYTEA_P(result);
}
 
Datum
sha384_bytea(PG_FUNCTION_ARGS)
{
    bytea      *result = cryptohash_internal(PG_SHA384, PG_GETARG_BYTEA_PP(0));
 
    PG_RETURN_BYTEA_P(result);
}
 
Datum
sha512_bytea(PG_FUNCTION_ARGS)
{
    bytea      *result = cryptohash_internal(PG_SHA512, PG_GETARG_BYTEA_PP(0));
 
    PG_RETURN_BYTEA_P(result);
}