Some word fixes.

[thirdparty/rsync.git] / checksum.c

/*
 * Routines to support checksumming of bytes.
 *
 * Copyright (C) 1996 Andrew Tridgell
 * Copyright (C) 1996 Paul Mackerras
 * Copyright (C) 2004-2020 Wayne Davison
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * In addition, as a special exception, the copyright holders give
 * permission to dynamically link rsync with the OpenSSL and xxhash
 * libraries when those libraries are being distributed in compliance
 * with their license terms, and to distribute a dynamically linked
 * combination of rsync and these libraries.  This is also considered
 * to be covered under the GPL's System Libraries exception.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, visit the http://fsf.org website.
 */

#include "rsync.h"

#ifdef SUPPORT_XXHASH
#include <xxhash.h>
# if XXH_VERSION_NUMBER >= 800
#  define SUPPORT_XXH3 1
# endif
#endif

extern int am_server;
extern int whole_file;
extern int checksum_seed;
extern int protocol_version;
extern int proper_seed_order;
extern const char *checksum_choice;

struct name_num_obj valid_checksums = {
        "checksum", NULL, NULL, 0, 0, {
#ifdef SUPPORT_XXH3
                { CSUM_XXH3_128, "xxh128", NULL },
                { CSUM_XXH3_64, "xxh3", NULL },
#endif
#ifdef SUPPORT_XXHASH
                { CSUM_XXH64, "xxh64", NULL },
                { CSUM_XXH64, "xxhash", NULL },
#endif
                { CSUM_MD5, "md5", NULL },
                { CSUM_MD4, "md4", NULL },
                { CSUM_NONE, "none", NULL },
                { 0, NULL, NULL }
        }
};

int xfersum_type = 0; /* used for the file transfer checksums */
int checksum_type = 0; /* used for the pre-transfer (--checksum) checksums */

int parse_csum_name(const char *name, int len)
{
        struct name_num_item *nni;

        if (len < 0 && name)
                len = strlen(name);

        if (!name || (len == 4 && strncasecmp(name, "auto", 4) == 0)) {
                if (protocol_version >= 30)
                        return CSUM_MD5;
                if (protocol_version >= 27)
                        return CSUM_MD4_OLD;
                if (protocol_version >= 21)
                        return CSUM_MD4_BUSTED;
                return CSUM_MD4_ARCHAIC;
        }

        nni = get_nni_by_name(&valid_checksums, name, len);

        if (!nni) {
                rprintf(FERROR, "unknown checksum name: %s\n", name);
                exit_cleanup(RERR_UNSUPPORTED);
        }

        return nni->num;
}

static const char *checksum_name(int num)
{
        struct name_num_item *nni = get_nni_by_num(&valid_checksums, num);

        return nni ? nni->name : num < CSUM_MD4 ? "md4" : "UNKNOWN";
}

void parse_checksum_choice(int final_call)
{
        if (valid_checksums.negotiated_name)
                xfersum_type = checksum_type = valid_checksums.negotiated_num;
        else {
                char *cp = checksum_choice ? strchr(checksum_choice, ',') : NULL;
                if (cp) {
                        xfersum_type = parse_csum_name(checksum_choice, cp - checksum_choice);
                        checksum_type = parse_csum_name(cp+1, -1);
                } else
                        xfersum_type = checksum_type = parse_csum_name(checksum_choice, -1);
                if (am_server && checksum_choice)
                        validate_choice_vs_env(NSTR_CHECKSUM, xfersum_type, checksum_type);
        }

        if (xfersum_type == CSUM_NONE)
                whole_file = 1;

        /* Snag the checksum name for both write_batch's option output & the following debug output. */
        if (valid_checksums.negotiated_name)
                checksum_choice = valid_checksums.negotiated_name;
        else if (checksum_choice == NULL)
                checksum_choice = checksum_name(xfersum_type);

        if (final_call && DEBUG_GTE(NSTR, am_server ? 3 : 1)) {
                rprintf(FINFO, "%s%s checksum: %s\n",
                        am_server ? "Server" : "Client",
                        valid_checksums.negotiated_name ? " negotiated" : "",
                        checksum_choice);
        }
}

int csum_len_for_type(int cst, BOOL flist_csum)
{
        switch (cst) {
          case CSUM_NONE:
                return 1;
          case CSUM_MD4_ARCHAIC:
                /* The oldest checksum code is rather weird: the file-list code only sent
                 * 2-byte checksums, but all other checksums were full MD4 length. */
                return flist_csum ? 2 : MD4_DIGEST_LEN;
          case CSUM_MD4:
          case CSUM_MD4_OLD:
          case CSUM_MD4_BUSTED:
                return MD4_DIGEST_LEN;
          case CSUM_MD5:
                return MD5_DIGEST_LEN;
          case CSUM_XXH64:
          case CSUM_XXH3_64:
                return 64/8;
          case CSUM_XXH3_128:
                return 128/8;
          default: /* paranoia to prevent missing case values */
                exit_cleanup(RERR_UNSUPPORTED);
        }
        return 0;
}

/* Returns 0 if the checksum is not canonical (i.e. it includes a seed value).
 * Returns 1 if the public sum order matches our internal sum order.
 * Returns -1 if the public sum order is the reverse of our internal sum order.
 */
int canonical_checksum(int csum_type)
{
        switch (csum_type) {
          case CSUM_NONE:
          case CSUM_MD4_ARCHAIC:
          case CSUM_MD4_OLD:
          case CSUM_MD4_BUSTED:
                break;
          case CSUM_MD4:
          case CSUM_MD5:
                return -1;
          case CSUM_XXH64:
          case CSUM_XXH3_64:
          case CSUM_XXH3_128:
                return 1;
          default: /* paranoia to prevent missing case values */
                exit_cleanup(RERR_UNSUPPORTED);
        }
        return 0;
}

#ifndef USE_ROLL_SIMD /* See simd-checksum-*.cpp. */
/*
  a simple 32 bit checksum that can be updated from either end
  (inspired by Mark Adler's Adler-32 checksum)
  */
uint32 get_checksum1(char *buf1, int32 len)
{
        int32 i;
        uint32 s1, s2;
        schar *buf = (schar *)buf1;

        s1 = s2 = 0;
        for (i = 0; i < (len-4); i+=4) {
                s2 += 4*(s1 + buf[i]) + 3*buf[i+1] + 2*buf[i+2] + buf[i+3] + 10*CHAR_OFFSET;
                s1 += (buf[i+0] + buf[i+1] + buf[i+2] + buf[i+3] + 4*CHAR_OFFSET);
        }
        for (; i < len; i++) {
                s1 += (buf[i]+CHAR_OFFSET); s2 += s1;
        }
        return (s1 & 0xffff) + (s2 << 16);
}
#endif

void get_checksum2(char *buf, int32 len, char *sum)
{
        switch (xfersum_type) {
#ifdef SUPPORT_XXHASH
          case CSUM_XXH64:
                SIVAL64(sum, 0, XXH64(buf, len, checksum_seed));
                break;
#endif
#ifdef SUPPORT_XXH3
          case CSUM_XXH3_64:
                SIVAL64(sum, 0, XXH3_64bits_withSeed(buf, len, checksum_seed));
                break;
          case CSUM_XXH3_128: {
                XXH128_hash_t digest = XXH3_128bits_withSeed(buf, len, checksum_seed);
                SIVAL64(sum, 0, digest.low64);
                SIVAL64(sum, 8, digest.high64);
                break;
          }
#endif
          case CSUM_MD5: {
                md5_context m5;
                uchar seedbuf[4];
                md5_begin(&m5);
                if (proper_seed_order) {
                        if (checksum_seed) {
                                SIVALu(seedbuf, 0, checksum_seed);
                                md5_update(&m5, seedbuf, 4);
                        }
                        md5_update(&m5, (uchar *)buf, len);
                } else {
                        md5_update(&m5, (uchar *)buf, len);
                        if (checksum_seed) {
                                SIVALu(seedbuf, 0, checksum_seed);
                                md5_update(&m5, seedbuf, 4);
                        }
                }
                md5_result(&m5, (uchar *)sum);
                break;
          }
          case CSUM_MD4:
#ifdef USE_OPENSSL
          {
                MD4_CTX m4;
                MD4_Init(&m4);
                MD4_Update(&m4, (uchar *)buf, len);
                if (checksum_seed) {
                        uchar seedbuf[4];
                        SIVALu(seedbuf, 0, checksum_seed);
                        MD4_Update(&m4, seedbuf, 4);
                }
                MD4_Final((uchar *)sum, &m4);
                break;
          }
#endif
          case CSUM_MD4_OLD:
          case CSUM_MD4_BUSTED:
          case CSUM_MD4_ARCHAIC: {
                md_context m;
                int32 i;
                static char *buf1;
                static int32 len1;

                mdfour_begin(&m);

                if (len > len1) {
                        if (buf1)
                                free(buf1);
                        buf1 = new_array(char, len+4);
                        len1 = len;
                }

                memcpy(buf1, buf, len);
                if (checksum_seed) {
                        SIVAL(buf1,len,checksum_seed);
                        len += 4;
                }

                for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK)
                        mdfour_update(&m, (uchar *)(buf1+i), CSUM_CHUNK);

                /*
                 * Prior to version 27 an incorrect MD4 checksum was computed
                 * by failing to call mdfour_tail() for block sizes that
                 * are multiples of 64.  This is fixed by calling mdfour_update()
                 * even when there are no more bytes.
                 */
                if (len - i > 0 || xfersum_type > CSUM_MD4_BUSTED)
                        mdfour_update(&m, (uchar *)(buf1+i), len-i);

                mdfour_result(&m, (uchar *)sum);
                break;
          }
          default: /* paranoia to prevent missing case values */
                exit_cleanup(RERR_UNSUPPORTED);
        }
}

void file_checksum(const char *fname, const STRUCT_STAT *st_p, char *sum)
{
        struct map_struct *buf;
        OFF_T i, len = st_p->st_size;
        int32 remainder;
        int fd;

        memset(sum, 0, MAX_DIGEST_LEN);

        fd = do_open(fname, O_RDONLY, 0);
        if (fd == -1)
                return;

        buf = map_file(fd, len, MAX_MAP_SIZE, CHUNK_SIZE);

        switch (checksum_type) {
#ifdef SUPPORT_XXHASH
          case CSUM_XXH64: {
                static XXH64_state_t* state = NULL;
                if (!state && !(state = XXH64_createState()))
                        out_of_memory("file_checksum");

                XXH64_reset(state, 0);

                for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE)
                        XXH64_update(state, (uchar *)map_ptr(buf, i, CHUNK_SIZE), CHUNK_SIZE);

                remainder = (int32)(len - i);
                if (remainder > 0)
                        XXH64_update(state, (uchar *)map_ptr(buf, i, remainder), remainder);

                SIVAL64(sum, 0, XXH64_digest(state));
                break;
          }
#endif
#ifdef SUPPORT_XXH3
          case CSUM_XXH3_64: {
                static XXH3_state_t* state = NULL;
                if (!state && !(state = XXH3_createState()))
                        out_of_memory("file_checksum");

                XXH3_64bits_reset(state);

                for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE)
                        XXH3_64bits_update(state, (uchar *)map_ptr(buf, i, CHUNK_SIZE), CHUNK_SIZE);

                remainder = (int32)(len - i);
                if (remainder > 0)
                        XXH3_64bits_update(state, (uchar *)map_ptr(buf, i, remainder), remainder);

                SIVAL64(sum, 0, XXH3_64bits_digest(state));
                break;
          }
          case CSUM_XXH3_128: {
                XXH128_hash_t digest;
                static XXH3_state_t* state = NULL;
                if (!state && !(state = XXH3_createState()))
                        out_of_memory("file_checksum");

                XXH3_128bits_reset(state);

                for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE)
                        XXH3_128bits_update(state, (uchar *)map_ptr(buf, i, CHUNK_SIZE), CHUNK_SIZE);

                remainder = (int32)(len - i);
                if (remainder > 0)
                        XXH3_128bits_update(state, (uchar *)map_ptr(buf, i, remainder), remainder);

                digest = XXH3_128bits_digest(state);
                SIVAL64(sum, 0, digest.low64);
                SIVAL64(sum, 8, digest.high64);
                break;
          }
#endif
          case CSUM_MD5: {
                md5_context m5;

                md5_begin(&m5);

                for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE)
                        md5_update(&m5, (uchar *)map_ptr(buf, i, CHUNK_SIZE), CHUNK_SIZE);

                remainder = (int32)(len - i);
                if (remainder > 0)
                        md5_update(&m5, (uchar *)map_ptr(buf, i, remainder), remainder);

                md5_result(&m5, (uchar *)sum);
                break;
          }
          case CSUM_MD4:
#ifdef USE_OPENSSL
          {
                MD4_CTX m4;

                MD4_Init(&m4);

                for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE)
                        MD4_Update(&m4, (uchar *)map_ptr(buf, i, CHUNK_SIZE), CHUNK_SIZE);

                remainder = (int32)(len - i);
                if (remainder > 0)
                        MD4_Update(&m4, (uchar *)map_ptr(buf, i, remainder), remainder);

                MD4_Final((uchar *)sum, &m4);
                break;
          }
#endif
          case CSUM_MD4_OLD:
          case CSUM_MD4_BUSTED:
          case CSUM_MD4_ARCHAIC: {
                md_context m;

                mdfour_begin(&m);

                for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE)
                        mdfour_update(&m, (uchar *)map_ptr(buf, i, CHUNK_SIZE), CHUNK_SIZE);

                /* Prior to version 27 an incorrect MD4 checksum was computed
                 * by failing to call mdfour_tail() for block sizes that
                 * are multiples of 64.  This is fixed by calling mdfour_update()
                 * even when there are no more bytes. */
                remainder = (int32)(len - i);
                if (remainder > 0 || checksum_type > CSUM_MD4_BUSTED)
                        mdfour_update(&m, (uchar *)map_ptr(buf, i, remainder), remainder);

                mdfour_result(&m, (uchar *)sum);
                break;
          }
          default:
                rprintf(FERROR, "Invalid checksum-choice for --checksum: %s (%d)\n",
                        checksum_name(checksum_type), checksum_type);
                exit_cleanup(RERR_UNSUPPORTED);
        }

        close(fd);
        unmap_file(buf);
}

static int32 sumresidue;
static union {
        md_context md;
#ifdef USE_OPENSSL
        MD4_CTX m4;
#endif
        md5_context m5;
} ctx;
#ifdef SUPPORT_XXHASH
static XXH64_state_t* xxh64_state;
#endif
#ifdef SUPPORT_XXH3
static XXH3_state_t* xxh3_state;
#endif
static int cursum_type;

void sum_init(int csum_type, int seed)
{
        char s[4];

        if (csum_type < 0)
                csum_type = parse_csum_name(NULL, 0);
        cursum_type = csum_type;

        switch (csum_type) {
#ifdef SUPPORT_XXHASH
          case CSUM_XXH64:
                if (!xxh64_state && !(xxh64_state = XXH64_createState()))
                        out_of_memory("sum_init");
                XXH64_reset(xxh64_state, 0);
                break;
#endif
#ifdef SUPPORT_XXH3
          case CSUM_XXH3_64:
                if (!xxh3_state && !(xxh3_state = XXH3_createState()))
                        out_of_memory("sum_init");
                XXH3_64bits_reset(xxh3_state);
                break;
          case CSUM_XXH3_128:
                if (!xxh3_state && !(xxh3_state = XXH3_createState()))
                        out_of_memory("sum_init");
                XXH3_128bits_reset(xxh3_state);
                break;
#endif
          case CSUM_MD5:
                md5_begin(&ctx.m5);
                break;
          case CSUM_MD4:
#ifdef USE_OPENSSL
                MD4_Init(&ctx.m4);
#else
                mdfour_begin(&ctx.md);
                sumresidue = 0;
#endif
                break;
          case CSUM_MD4_OLD:
          case CSUM_MD4_BUSTED:
          case CSUM_MD4_ARCHAIC:
                mdfour_begin(&ctx.md);
                sumresidue = 0;
                SIVAL(s, 0, seed);
                sum_update(s, 4);
                break;
          case CSUM_NONE:
                break;
          default: /* paranoia to prevent missing case values */
                exit_cleanup(RERR_UNSUPPORTED);
        }
}

/**
 * Feed data into an MD4 accumulator, md.  The results may be
 * retrieved using sum_end().  md is used for different purposes at
 * different points during execution.
 *
 * @todo Perhaps get rid of md and just pass in the address each time.
 * Very slightly clearer and slower.
 **/
void sum_update(const char *p, int32 len)
{
        switch (cursum_type) {
#ifdef SUPPORT_XXHASH
          case CSUM_XXH64:
                XXH64_update(xxh64_state, p, len);
                break;
#endif
#ifdef SUPPORT_XXH3
          case CSUM_XXH3_64:
                XXH3_64bits_update(xxh3_state, p, len);
                break;
          case CSUM_XXH3_128:
                XXH3_128bits_update(xxh3_state, p, len);
                break;
#endif
          case CSUM_MD5:
                md5_update(&ctx.m5, (uchar *)p, len);
                break;
          case CSUM_MD4:
#ifdef USE_OPENSSL
                MD4_Update(&ctx.m4, (uchar *)p, len);
                break;
#endif
          case CSUM_MD4_OLD:
          case CSUM_MD4_BUSTED:
          case CSUM_MD4_ARCHAIC:
                if (len + sumresidue < CSUM_CHUNK) {
                        memcpy(ctx.md.buffer + sumresidue, p, len);
                        sumresidue += len;
                        break;
                }

                if (sumresidue) {
                        int32 i = CSUM_CHUNK - sumresidue;
                        memcpy(ctx.md.buffer + sumresidue, p, i);
                        mdfour_update(&ctx.md, (uchar *)ctx.md.buffer, CSUM_CHUNK);
                        len -= i;
                        p += i;
                }

                while (len >= CSUM_CHUNK) {
                        mdfour_update(&ctx.md, (uchar *)p, CSUM_CHUNK);
                        len -= CSUM_CHUNK;
                        p += CSUM_CHUNK;
                }

                sumresidue = len;
                if (sumresidue)
                        memcpy(ctx.md.buffer, p, sumresidue);
                break;
          case CSUM_NONE:
                break;
          default: /* paranoia to prevent missing case values */
                exit_cleanup(RERR_UNSUPPORTED);
        }
}

/* NOTE: all the callers of sum_end() pass in a pointer to a buffer that is
 * MAX_DIGEST_LEN in size, so even if the csum-len is shorter that that (i.e.
 * CSUM_MD4_ARCHAIC), we don't have to worry about limiting the data we write
 * into the "sum" buffer. */
int sum_end(char *sum)
{
        switch (cursum_type) {
#ifdef SUPPORT_XXHASH
          case CSUM_XXH64:
                SIVAL64(sum, 0, XXH64_digest(xxh64_state));
                break;
#endif
#ifdef SUPPORT_XXH3
          case CSUM_XXH3_64:
                SIVAL64(sum, 0, XXH3_64bits_digest(xxh3_state));
                break;
          case CSUM_XXH3_128: {
                XXH128_hash_t digest = XXH3_128bits_digest(xxh3_state);
                SIVAL64(sum, 0, digest.low64);
                SIVAL64(sum, 8, digest.high64);
                break;
          }
#endif
          case CSUM_MD5:
                md5_result(&ctx.m5, (uchar *)sum);
                break;
          case CSUM_MD4:
#ifdef USE_OPENSSL
                MD4_Final((uchar *)sum, &ctx.m4);
                break;
#endif
          case CSUM_MD4_OLD:
                mdfour_update(&ctx.md, (uchar *)ctx.md.buffer, sumresidue);
                mdfour_result(&ctx.md, (uchar *)sum);
                break;
          case CSUM_MD4_BUSTED:
          case CSUM_MD4_ARCHAIC:
                if (sumresidue)
                        mdfour_update(&ctx.md, (uchar *)ctx.md.buffer, sumresidue);
                mdfour_result(&ctx.md, (uchar *)sum);
                break;
          case CSUM_NONE:
                *sum = '\0';
                break;
          default: /* paranoia to prevent missing case values */
                exit_cleanup(RERR_UNSUPPORTED);
        }

        return csum_len_for_type(cursum_type, 0);
}