cryptohash.c

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/*-------------------------------------------------------------------------
 *
 * cryptohash.c
 *    Fallback implementations for cryptographic hash functions.
 *
 * This is the set of in-core functions used when there are no other
 * alternative options like OpenSSL.
 *
 * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *    src/common/cryptohash.c
 *
 *-------------------------------------------------------------------------
 */
 
#ifndef FRONTEND
#include "postgres.h"
#else
#include "postgres_fe.h"
#endif
 
#include <sys/param.h>
 
#include "common/cryptohash.h"
#include "md5_int.h"
#include "sha1_int.h"
#include "sha2_int.h"
 
/*
 * In backend, use palloc/pfree to ease the error handling.  In frontend,
 * use malloc to be able to return a failure status back to the caller.
 */
#ifndef FRONTEND
#define ALLOC(size) palloc(size)
#define FREE(ptr) pfree(ptr)
#else
#define ALLOC(size) malloc(size)
#define FREE(ptr) free(ptr)
#endif
 
/* Set of error states */
typedef enum pg_cryptohash_errno
{
    PG_CRYPTOHASH_ERROR_NONE = 0,
    PG_CRYPTOHASH_ERROR_DEST_LEN,
} pg_cryptohash_errno;
 
/* Internal pg_cryptohash_ctx structure */
struct pg_cryptohash_ctx
{
    pg_cryptohash_type type;
    pg_cryptohash_errno error;
 
    union
    {
        pg_md5_ctx  md5;
        pg_sha1_ctx sha1;
        pg_sha224_ctx sha224;
        pg_sha256_ctx sha256;
        pg_sha384_ctx sha384;
        pg_sha512_ctx sha512;
    }           data;
};
 
/*
 * pg_cryptohash_create
 *
 * Allocate a hash context.  Returns NULL on failure for an OOM.  The
 * backend issues an error, without returning.
 */
pg_cryptohash_ctx *
pg_cryptohash_create(pg_cryptohash_type type)
{
    pg_cryptohash_ctx *ctx;
 
    /*
     * Note that this always allocates enough space for the largest hash. A
     * smaller allocation would be enough for md5, sha224 and sha256, but the
     * small extra amount of memory does not make it worth complicating this
     * code.
     */
    ctx = ALLOC(sizeof(pg_cryptohash_ctx));
    if (ctx == NULL)
        return NULL;
 
    memset(ctx, 0, sizeof(pg_cryptohash_ctx));
    ctx->type = type;
    ctx->error = PG_CRYPTOHASH_ERROR_NONE;
    return ctx;
}
 
/*
 * pg_cryptohash_init
 *
 * Initialize a hash context.  Returns 0 on success, and -1 on failure.
 */
int
pg_cryptohash_init(pg_cryptohash_ctx *ctx)
{
    if (ctx == NULL)
        return -1;
 
    switch (ctx->type)
    {
        case PG_MD5:
            pg_md5_init(&ctx->data.md5);
            break;
        case PG_SHA1:
            pg_sha1_init(&ctx->data.sha1);
            break;
        case PG_SHA224:
            pg_sha224_init(&ctx->data.sha224);
            break;
        case PG_SHA256:
            pg_sha256_init(&ctx->data.sha256);
            break;
        case PG_SHA384:
            pg_sha384_init(&ctx->data.sha384);
            break;
        case PG_SHA512:
            pg_sha512_init(&ctx->data.sha512);
            break;
    }
 
    return 0;
}
 
/*
 * pg_cryptohash_update
 *
 * Update a hash context.  Returns 0 on success, and -1 on failure.
 */
int
pg_cryptohash_update(pg_cryptohash_ctx *ctx, const uint8 *data, size_t len)
{
    if (ctx == NULL)
        return -1;
 
    switch (ctx->type)
    {
        case PG_MD5:
            pg_md5_update(&ctx->data.md5, data, len);
            break;
        case PG_SHA1:
            pg_sha1_update(&ctx->data.sha1, data, len);
            break;
        case PG_SHA224:
            pg_sha224_update(&ctx->data.sha224, data, len);
            break;
        case PG_SHA256:
            pg_sha256_update(&ctx->data.sha256, data, len);
            break;
        case PG_SHA384:
            pg_sha384_update(&ctx->data.sha384, data, len);
            break;
        case PG_SHA512:
            pg_sha512_update(&ctx->data.sha512, data, len);
            break;
    }
 
    return 0;
}
 
/*
 * pg_cryptohash_final
 *
 * Finalize a hash context.  Returns 0 on success, and -1 on failure.
 */
int
pg_cryptohash_final(pg_cryptohash_ctx *ctx, uint8 *dest, size_t len)
{
    if (ctx == NULL)
        return -1;
 
    switch (ctx->type)
    {
        case PG_MD5:
            if (len < MD5_DIGEST_LENGTH)
            {
                ctx->error = PG_CRYPTOHASH_ERROR_DEST_LEN;
                return -1;
            }
            pg_md5_final(&ctx->data.md5, dest);
            break;
        case PG_SHA1:
            if (len < SHA1_DIGEST_LENGTH)
            {
                ctx->error = PG_CRYPTOHASH_ERROR_DEST_LEN;
                return -1;
            }
            pg_sha1_final(&ctx->data.sha1, dest);
            break;
        case PG_SHA224:
            if (len < PG_SHA224_DIGEST_LENGTH)
            {
                ctx->error = PG_CRYPTOHASH_ERROR_DEST_LEN;
                return -1;
            }
            pg_sha224_final(&ctx->data.sha224, dest);
            break;
        case PG_SHA256:
            if (len < PG_SHA256_DIGEST_LENGTH)
            {
                ctx->error = PG_CRYPTOHASH_ERROR_DEST_LEN;
                return -1;
            }
            pg_sha256_final(&ctx->data.sha256, dest);
            break;
        case PG_SHA384:
            if (len < PG_SHA384_DIGEST_LENGTH)
            {
                ctx->error = PG_CRYPTOHASH_ERROR_DEST_LEN;
                return -1;
            }
            pg_sha384_final(&ctx->data.sha384, dest);
            break;
        case PG_SHA512:
            if (len < PG_SHA512_DIGEST_LENGTH)
            {
                ctx->error = PG_CRYPTOHASH_ERROR_DEST_LEN;
                return -1;
            }
            pg_sha512_final(&ctx->data.sha512, dest);
            break;
    }
 
    return 0;
}
 
/*
 * pg_cryptohash_free
 *
 * Free a hash context.
 */
void
pg_cryptohash_free(pg_cryptohash_ctx *ctx)
{
    if (ctx == NULL)
        return;
 
    explicit_bzero(ctx, sizeof(pg_cryptohash_ctx));
    FREE(ctx);
}
 
/*
 * pg_cryptohash_error
 *
 * Returns a static string providing details about an error that
 * happened during a computation.
 */
const char *
pg_cryptohash_error(pg_cryptohash_ctx *ctx)
{
    /*
     * This implementation would never fail because of an out-of-memory error,
     * except when creating the context.
     */
    if (ctx == NULL)
        return _("out of memory");
 
    switch (ctx->error)
    {
        case PG_CRYPTOHASH_ERROR_NONE:
            return _("success");
        case PG_CRYPTOHASH_ERROR_DEST_LEN:
            return _("destination buffer too small");
    }
 
    Assert(false);
    return _("success");
}