checksum_helper.c

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/*-------------------------------------------------------------------------
 *
 * checksum_helper.c
 *    Compute a checksum of any of various types using common routines
 *
 * Portions Copyright (c) 2016-2024, PostgreSQL Global Development Group
 *
 * IDENTIFICATION
 *        src/common/checksum_helper.c
 *
 *-------------------------------------------------------------------------
 */
 
#ifndef FRONTEND
#include "postgres.h"
#else
#include "postgres_fe.h"
#endif
 
#include "common/checksum_helper.h"
 
/*
 * If 'name' is a recognized checksum type, set *type to the corresponding
 * constant and return true. Otherwise, set *type to CHECKSUM_TYPE_NONE and
 * return false.
 */
bool
pg_checksum_parse_type(char *name, pg_checksum_type *type)
{
    pg_checksum_type result_type = CHECKSUM_TYPE_NONE;
    bool        result = true;
 
    if (pg_strcasecmp(name, "none") == 0)
        result_type = CHECKSUM_TYPE_NONE;
    else if (pg_strcasecmp(name, "crc32c") == 0)
        result_type = CHECKSUM_TYPE_CRC32C;
    else if (pg_strcasecmp(name, "sha224") == 0)
        result_type = CHECKSUM_TYPE_SHA224;
    else if (pg_strcasecmp(name, "sha256") == 0)
        result_type = CHECKSUM_TYPE_SHA256;
    else if (pg_strcasecmp(name, "sha384") == 0)
        result_type = CHECKSUM_TYPE_SHA384;
    else if (pg_strcasecmp(name, "sha512") == 0)
        result_type = CHECKSUM_TYPE_SHA512;
    else
        result = false;
 
    *type = result_type;
    return result;
}
 
/*
 * Get the canonical human-readable name corresponding to a checksum type.
 */
char *
pg_checksum_type_name(pg_checksum_type type)
{
    switch (type)
    {
        case CHECKSUM_TYPE_NONE:
            return "NONE";
        case CHECKSUM_TYPE_CRC32C:
            return "CRC32C";
        case CHECKSUM_TYPE_SHA224:
            return "SHA224";
        case CHECKSUM_TYPE_SHA256:
            return "SHA256";
        case CHECKSUM_TYPE_SHA384:
            return "SHA384";
        case CHECKSUM_TYPE_SHA512:
            return "SHA512";
    }
 
    Assert(false);
    return "???";
}
 
/*
 * Initialize a checksum context for checksums of the given type.
 * Returns 0 for a success, -1 for a failure.
 */
int
pg_checksum_init(pg_checksum_context *context, pg_checksum_type type)
{
    context->type = type;
 
    switch (type)
    {
        case CHECKSUM_TYPE_NONE:
            /* do nothing */
            break;
        case CHECKSUM_TYPE_CRC32C:
            INIT_CRC32C(context->raw_context.c_crc32c);
            break;
        case CHECKSUM_TYPE_SHA224:
            context->raw_context.c_sha2 = pg_cryptohash_create(PG_SHA224);
            if (context->raw_context.c_sha2 == NULL)
                return -1;
            if (pg_cryptohash_init(context->raw_context.c_sha2) < 0)
            {
                pg_cryptohash_free(context->raw_context.c_sha2);
                return -1;
            }
            break;
        case CHECKSUM_TYPE_SHA256:
            context->raw_context.c_sha2 = pg_cryptohash_create(PG_SHA256);
            if (context->raw_context.c_sha2 == NULL)
                return -1;
            if (pg_cryptohash_init(context->raw_context.c_sha2) < 0)
            {
                pg_cryptohash_free(context->raw_context.c_sha2);
                return -1;
            }
            break;
        case CHECKSUM_TYPE_SHA384:
            context->raw_context.c_sha2 = pg_cryptohash_create(PG_SHA384);
            if (context->raw_context.c_sha2 == NULL)
                return -1;
            if (pg_cryptohash_init(context->raw_context.c_sha2) < 0)
            {
                pg_cryptohash_free(context->raw_context.c_sha2);
                return -1;
            }
            break;
        case CHECKSUM_TYPE_SHA512:
            context->raw_context.c_sha2 = pg_cryptohash_create(PG_SHA512);
            if (context->raw_context.c_sha2 == NULL)
                return -1;
            if (pg_cryptohash_init(context->raw_context.c_sha2) < 0)
            {
                pg_cryptohash_free(context->raw_context.c_sha2);
                return -1;
            }
            break;
    }
 
    return 0;
}
 
/*
 * Update a checksum context with new data.
 * Returns 0 for a success, -1 for a failure.
 */
int
pg_checksum_update(pg_checksum_context *context, const uint8 *input,
                   size_t len)
{
    switch (context->type)
    {
        case CHECKSUM_TYPE_NONE:
            /* do nothing */
            break;
        case CHECKSUM_TYPE_CRC32C:
            COMP_CRC32C(context->raw_context.c_crc32c, input, len);
            break;
        case CHECKSUM_TYPE_SHA224:
        case CHECKSUM_TYPE_SHA256:
        case CHECKSUM_TYPE_SHA384:
        case CHECKSUM_TYPE_SHA512:
            if (pg_cryptohash_update(context->raw_context.c_sha2, input, len) < 0)
                return -1;
            break;
    }
 
    return 0;
}
 
/*
 * Finalize a checksum computation and write the result to an output buffer.
 *
 * The caller must ensure that the buffer is at least PG_CHECKSUM_MAX_LENGTH
 * bytes in length. The return value is the number of bytes actually written,
 * or -1 for a failure.
 */
int
pg_checksum_final(pg_checksum_context *context, uint8 *output)
{
    int         retval = 0;
 
    StaticAssertDecl(sizeof(pg_crc32c) <= PG_CHECKSUM_MAX_LENGTH,
                     "CRC-32C digest too big for PG_CHECKSUM_MAX_LENGTH");
    StaticAssertDecl(PG_SHA224_DIGEST_LENGTH <= PG_CHECKSUM_MAX_LENGTH,
                     "SHA224 digest too big for PG_CHECKSUM_MAX_LENGTH");
    StaticAssertDecl(PG_SHA256_DIGEST_LENGTH <= PG_CHECKSUM_MAX_LENGTH,
                     "SHA256 digest too big for PG_CHECKSUM_MAX_LENGTH");
    StaticAssertDecl(PG_SHA384_DIGEST_LENGTH <= PG_CHECKSUM_MAX_LENGTH,
                     "SHA384 digest too big for PG_CHECKSUM_MAX_LENGTH");
    StaticAssertDecl(PG_SHA512_DIGEST_LENGTH <= PG_CHECKSUM_MAX_LENGTH,
                     "SHA512 digest too big for PG_CHECKSUM_MAX_LENGTH");
 
    switch (context->type)
    {
        case CHECKSUM_TYPE_NONE:
            break;
        case CHECKSUM_TYPE_CRC32C:
            FIN_CRC32C(context->raw_context.c_crc32c);
            retval = sizeof(pg_crc32c);
            memcpy(output, &context->raw_context.c_crc32c, retval);
            break;
        case CHECKSUM_TYPE_SHA224:
            retval = PG_SHA224_DIGEST_LENGTH;
            if (pg_cryptohash_final(context->raw_context.c_sha2,
                                    output, retval) < 0)
                return -1;
            pg_cryptohash_free(context->raw_context.c_sha2);
            break;
        case CHECKSUM_TYPE_SHA256:
            retval = PG_SHA256_DIGEST_LENGTH;
            if (pg_cryptohash_final(context->raw_context.c_sha2,
                                    output, retval) < 0)
                return -1;
            pg_cryptohash_free(context->raw_context.c_sha2);
            break;
        case CHECKSUM_TYPE_SHA384:
            retval = PG_SHA384_DIGEST_LENGTH;
            if (pg_cryptohash_final(context->raw_context.c_sha2,
                                    output, retval) < 0)
                return -1;
            pg_cryptohash_free(context->raw_context.c_sha2);
            break;
        case CHECKSUM_TYPE_SHA512:
            retval = PG_SHA512_DIGEST_LENGTH;
            if (pg_cryptohash_final(context->raw_context.c_sha2,
                                    output, retval) < 0)
                return -1;
            pg_cryptohash_free(context->raw_context.c_sha2);
            break;
    }
 
    Assert(retval <= PG_CHECKSUM_MAX_LENGTH);
    return retval;
}