diff options
Diffstat (limited to 'lib/scryptenc/scryptenc.c')
| -rw-r--r-- | lib/scryptenc/scryptenc.c | 605 |
1 files changed, 0 insertions, 605 deletions
diff --git a/lib/scryptenc/scryptenc.c b/lib/scryptenc/scryptenc.c deleted file mode 100644 index cf091bf..0000000 --- a/lib/scryptenc/scryptenc.c +++ /dev/null @@ -1,605 +0,0 @@ -/*- - * Copyright 2009 Colin Percival - * All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * - * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND - * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE - * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL - * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS - * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY - * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF - * SUCH DAMAGE. - * - * This file was originally written by Colin Percival as part of the Tarsnap - * online backup system. - */ - -#include <errno.h> -#include <fcntl.h> -#include <stdint.h> -#include <stdio.h> -#include <string.h> -#include <unistd.h> - -#include <openssl/aes.h> - -#include "crypto_aesctr.h" -#include "crypto_scrypt.h" -#include "memlimit.h" -#include "scryptenc_cpuperf.h" -#include "sha256.h" -#include "sysendian.h" - -#include "scryptenc.h" - -#define ENCBLOCK 65536 - -static int pickparams(size_t, double, double, - int *, uint32_t *, uint32_t *); -static int checkparams(size_t, double, double, int, uint32_t, uint32_t); -static int getsalt(uint8_t[32]); - -static int -pickparams(size_t maxmem, double maxmemfrac, double maxtime, - int * logN, uint32_t * r, uint32_t * p) -{ - size_t memlimit; - double opps; - double opslimit; - double maxN, maxrp; - int rc; - - /* Figure out how much memory to use. */ - if (memtouse(maxmem, maxmemfrac, &memlimit)) - return (1); - - /* Figure out how fast the CPU is. */ - if ((rc = scryptenc_cpuperf(&opps)) != 0) - return (rc); - opslimit = opps * maxtime; - - /* Allow a minimum of 2^15 salsa20/8 cores. */ - if (opslimit < 32768) - opslimit = 32768; - - /* Fix r = 8 for now. */ - *r = 8; - - /* - * The memory limit requires that 128Nr <= memlimit, while the CPU - * limit requires that 4Nrp <= opslimit. If opslimit < memlimit/32, - * opslimit imposes the stronger limit on N. - */ -#ifdef DEBUG - fprintf(stderr, "Requiring 128Nr <= %zu, 4Nrp <= %f\n", - memlimit, opslimit); -#endif - if (opslimit < memlimit/32) { - /* Set p = 1 and choose N based on the CPU limit. */ - *p = 1; - maxN = opslimit / (*r * 4); - for (*logN = 1; *logN < 63; *logN += 1) { - if ((uint64_t)(1) << *logN > maxN / 2) - break; - } - } else { - /* Set N based on the memory limit. */ - maxN = memlimit / (*r * 128); - for (*logN = 1; *logN < 63; *logN += 1) { - if ((uint64_t)(1) << *logN > maxN / 2) - break; - } - - /* Choose p based on the CPU limit. */ - maxrp = (opslimit / 4) / ((uint64_t)(1) << *logN); - if (maxrp > 0x3fffffff) - maxrp = 0x3fffffff; - *p = (uint32_t)(maxrp) / *r; - } - -#ifdef DEBUG - fprintf(stderr, "N = %zu r = %d p = %d\n", - (size_t)(1) << *logN, (int)(*r), (int)(*p)); -#endif - - /* Success! */ - return (0); -} - -static int -checkparams(size_t maxmem, double maxmemfrac, double maxtime, - int logN, uint32_t r, uint32_t p) -{ - size_t memlimit; - double opps; - double opslimit; - uint64_t N; - int rc; - - /* Figure out the maximum amount of memory we can use. */ - if (memtouse(maxmem, maxmemfrac, &memlimit)) - return (1); - - /* Figure out how fast the CPU is. */ - if ((rc = scryptenc_cpuperf(&opps)) != 0) - return (rc); - opslimit = opps * maxtime; - - /* Sanity-check values. */ - if ((logN < 1) || (logN > 63)) - return (7); - if ((uint64_t)(r) * (uint64_t)(p) >= 0x40000000) - return (7); - - /* Check limits. */ - N = (uint64_t)(1) << logN; - if ((memlimit / N) / r < 128) - return (9); - if ((opslimit / N) / (r * p) < 4) - return (10); - - /* Success! */ - return (0); -} - -static int -getsalt(uint8_t salt[32]) -{ - int fd; - ssize_t lenread; - uint8_t * buf = salt; - size_t buflen = 32; - - /* Open /dev/urandom. */ - if ((fd = open("/dev/urandom", O_RDONLY)) == -1) - goto err0; - - /* Read bytes until we have filled the buffer. */ - while (buflen > 0) { - if ((lenread = read(fd, buf, buflen)) == -1) - goto err1; - - /* The random device should never EOF. */ - if (lenread == 0) - goto err1; - - /* We're partly done. */ - buf += lenread; - buflen -= lenread; - } - - /* Close the device. */ - while (close(fd) == -1) { - if (errno != EINTR) - goto err0; - } - - /* Success! */ - return (0); - -err1: - close(fd); -err0: - /* Failure! */ - return (4); -} - -static int -scryptenc_setup(uint8_t header[96], uint8_t dk[64], - const uint8_t * passwd, size_t passwdlen, - size_t maxmem, double maxmemfrac, double maxtime) -{ - uint8_t salt[32]; - uint8_t hbuf[32]; - int logN; - uint64_t N; - uint32_t r; - uint32_t p; - SHA256_CTX ctx; - uint8_t * key_hmac = &dk[32]; - HMAC_SHA256_CTX hctx; - int rc; - - /* Pick values for N, r, p. */ - if ((rc = pickparams(maxmem, maxmemfrac, maxtime, - &logN, &r, &p)) != 0) - return (rc); - N = (uint64_t)(1) << logN; - - /* Get some salt. */ - if ((rc = getsalt(salt)) != 0) - return (rc); - - /* Generate the derived keys. */ - if (crypto_scrypt(passwd, passwdlen, salt, 32, N, r, p, dk, 64)) - return (3); - - /* Construct the file header. */ - memcpy(header, "scrypt", 6); - header[6] = 0; - header[7] = logN; - be32enc(&header[8], r); - be32enc(&header[12], p); - memcpy(&header[16], salt, 32); - - /* Add header checksum. */ - SHA256_Init(&ctx); - SHA256_Update(&ctx, header, 48); - SHA256_Final(hbuf, &ctx); - memcpy(&header[48], hbuf, 16); - - /* Add header signature (used for verifying password). */ - HMAC_SHA256_Init(&hctx, key_hmac, 32); - HMAC_SHA256_Update(&hctx, header, 64); - HMAC_SHA256_Final(hbuf, &hctx); - memcpy(&header[64], hbuf, 32); - - /* Success! */ - return (0); -} - -static int -scryptdec_setup(const uint8_t header[96], uint8_t dk[64], - const uint8_t * passwd, size_t passwdlen, - size_t maxmem, double maxmemfrac, double maxtime) -{ - uint8_t salt[32]; - uint8_t hbuf[32]; - int logN; - uint32_t r; - uint32_t p; - uint64_t N; - SHA256_CTX ctx; - uint8_t * key_hmac = &dk[32]; - HMAC_SHA256_CTX hctx; - int rc; - - /* Parse N, r, p, salt. */ - logN = header[7]; - r = be32dec(&header[8]); - p = be32dec(&header[12]); - memcpy(salt, &header[16], 32); - - /* Verify header checksum. */ - SHA256_Init(&ctx); - SHA256_Update(&ctx, header, 48); - SHA256_Final(hbuf, &ctx); - if (memcmp(&header[48], hbuf, 16)) - return (7); - - /* - * Check whether the provided parameters are valid and whether the - * key derivation function can be computed within the allowed memory - * and CPU time. - */ - if ((rc = checkparams(maxmem, maxmemfrac, maxtime, logN, r, p)) != 0) - return (rc); - - /* Compute the derived keys. */ - N = (uint64_t)(1) << logN; - if (crypto_scrypt(passwd, passwdlen, salt, 32, N, r, p, dk, 64)) - return (3); - - /* Check header signature (i.e., verify password). */ - HMAC_SHA256_Init(&hctx, key_hmac, 32); - HMAC_SHA256_Update(&hctx, header, 64); - HMAC_SHA256_Final(hbuf, &hctx); - if (memcmp(hbuf, &header[64], 32)) - return (11); - - /* Success! */ - return (0); -} - -/** - * scryptenc_buf(inbuf, inbuflen, outbuf, passwd, passwdlen, - * maxmem, maxmemfrac, maxtime): - * Encrypt inbuflen bytes from inbuf, writing the resulting inbuflen + 128 - * bytes to outbuf. - */ -int -scryptenc_buf(const uint8_t * inbuf, size_t inbuflen, uint8_t * outbuf, - const uint8_t * passwd, size_t passwdlen, - size_t maxmem, double maxmemfrac, double maxtime) -{ - uint8_t dk[64]; - uint8_t hbuf[32]; - uint8_t header[96]; - uint8_t * key_enc = dk; - uint8_t * key_hmac = &dk[32]; - int rc; - HMAC_SHA256_CTX hctx; - AES_KEY key_enc_exp; - struct crypto_aesctr * AES; - - /* Generate the header and derived key. */ - if ((rc = scryptenc_setup(header, dk, passwd, passwdlen, - maxmem, maxmemfrac, maxtime)) != 0) - return (rc); - - /* Copy header into output buffer. */ - memcpy(outbuf, header, 96); - - /* Encrypt data. */ - if (AES_set_encrypt_key(key_enc, 256, &key_enc_exp)) - return (5); - if ((AES = crypto_aesctr_init(&key_enc_exp, 0)) == NULL) - return (6); - crypto_aesctr_stream(AES, inbuf, &outbuf[96], inbuflen); - crypto_aesctr_free(AES); - - /* Add signature. */ - HMAC_SHA256_Init(&hctx, key_hmac, 32); - HMAC_SHA256_Update(&hctx, outbuf, 96 + inbuflen); - HMAC_SHA256_Final(hbuf, &hctx); - memcpy(&outbuf[96 + inbuflen], hbuf, 32); - - /* Zero sensitive data. */ - memset(dk, 0, 64); - memset(&key_enc_exp, 0, sizeof(AES_KEY)); - - /* Success! */ - return (0); -} - -/** - * scryptdec_buf(inbuf, inbuflen, outbuf, outlen, passwd, passwdlen, - * maxmem, maxmemfrac, maxtime): - * Decrypt inbuflen bytes fro inbuf, writing the result into outbuf and the - * decrypted data length to outlen. The allocated length of outbuf must - * be at least inbuflen. - */ -int -scryptdec_buf(const uint8_t * inbuf, size_t inbuflen, uint8_t * outbuf, - size_t * outlen, const uint8_t * passwd, size_t passwdlen, - size_t maxmem, double maxmemfrac, double maxtime) -{ - uint8_t hbuf[32]; - uint8_t dk[64]; - uint8_t * key_enc = dk; - uint8_t * key_hmac = &dk[32]; - int rc; - HMAC_SHA256_CTX hctx; - AES_KEY key_enc_exp; - struct crypto_aesctr * AES; - - /* - * All versions of the scrypt format will start with "scrypt" and - * have at least 7 bytes of header. - */ - if ((inbuflen < 7) || (memcmp(inbuf, "scrypt", 6) != 0)) - return (7); - - /* Check the format. */ - if (inbuf[6] != 0) - return (8); - - /* We must have at least 128 bytes. */ - if (inbuflen < 128) - return (7); - - /* Parse the header and generate derived keys. */ - if ((rc = scryptdec_setup(inbuf, dk, passwd, passwdlen, - maxmem, maxmemfrac, maxtime)) != 0) - return (rc); - - /* Decrypt data. */ - if (AES_set_encrypt_key(key_enc, 256, &key_enc_exp)) - return (5); - if ((AES = crypto_aesctr_init(&key_enc_exp, 0)) == NULL) - return (6); - crypto_aesctr_stream(AES, &inbuf[96], outbuf, inbuflen - 128); - crypto_aesctr_free(AES); - *outlen = inbuflen - 128; - - /* Verify signature. */ - HMAC_SHA256_Init(&hctx, key_hmac, 32); - HMAC_SHA256_Update(&hctx, inbuf, inbuflen - 32); - HMAC_SHA256_Final(hbuf, &hctx); - if (memcmp(hbuf, &inbuf[inbuflen - 32], 32)) - return (7); - - /* Zero sensitive data. */ - memset(dk, 0, 64); - memset(&key_enc_exp, 0, sizeof(AES_KEY)); - - /* Success! */ - return (0); -} - -/** - * scryptenc_file(infile, outfile, passwd, passwdlen, - * maxmem, maxmemfrac, maxtime): - * Read a stream from infile and encrypt it, writing the resulting stream to - * outfile. - */ -int -scryptenc_file(FILE * infile, FILE * outfile, - const uint8_t * passwd, size_t passwdlen, - size_t maxmem, double maxmemfrac, double maxtime) -{ - uint8_t buf[ENCBLOCK]; - uint8_t dk[64]; - uint8_t hbuf[32]; - uint8_t header[96]; - uint8_t * key_enc = dk; - uint8_t * key_hmac = &dk[32]; - size_t readlen; - HMAC_SHA256_CTX hctx; - AES_KEY key_enc_exp; - struct crypto_aesctr * AES; - int rc; - - /* Generate the header and derived key. */ - if ((rc = scryptenc_setup(header, dk, passwd, passwdlen, - maxmem, maxmemfrac, maxtime)) != 0) - return (rc); - - /* Hash and write the header. */ - HMAC_SHA256_Init(&hctx, key_hmac, 32); - HMAC_SHA256_Update(&hctx, header, 96); - if (fwrite(header, 96, 1, outfile) != 1) - return (12); - - /* - * Read blocks of data, encrypt them, and write them out; hash the - * data as it is produced. - */ - if (AES_set_encrypt_key(key_enc, 256, &key_enc_exp)) - return (5); - if ((AES = crypto_aesctr_init(&key_enc_exp, 0)) == NULL) - return (6); - do { - if ((readlen = fread(buf, 1, ENCBLOCK, infile)) == 0) - break; - crypto_aesctr_stream(AES, buf, buf, readlen); - HMAC_SHA256_Update(&hctx, buf, readlen); - if (fwrite(buf, 1, readlen, outfile) < readlen) - return (12); - } while (1); - crypto_aesctr_free(AES); - - /* Did we exit the loop due to a read error? */ - if (ferror(infile)) - return (13); - - /* Compute the final HMAC and output it. */ - HMAC_SHA256_Final(hbuf, &hctx); - if (fwrite(hbuf, 32, 1, outfile) != 1) - return (12); - - /* Zero sensitive data. */ - memset(dk, 0, 64); - memset(&key_enc_exp, 0, sizeof(AES_KEY)); - - /* Success! */ - return (0); -} - -/** - * scryptdec_file(infile, outfile, passwd, passwdlen, - * maxmem, maxmemfrac, maxtime): - * Read a stream from infile and decrypt it, writing the resulting stream to - * outfile. - */ -int -scryptdec_file(FILE * infile, FILE * outfile, - const uint8_t * passwd, size_t passwdlen, - size_t maxmem, double maxmemfrac, double maxtime) -{ - uint8_t buf[ENCBLOCK + 32]; - uint8_t header[96]; - uint8_t hbuf[32]; - uint8_t dk[64]; - uint8_t * key_enc = dk; - uint8_t * key_hmac = &dk[32]; - size_t buflen = 0; - size_t readlen; - HMAC_SHA256_CTX hctx; - AES_KEY key_enc_exp; - struct crypto_aesctr * AES; - int rc; - - /* - * Read the first 7 bytes of the file; all future version of scrypt - * are guaranteed to have at least 7 bytes of header. - */ - if (fread(header, 7, 1, infile) < 1) { - if (ferror(infile)) - return (13); - else - return (7); - } - - /* Do we have the right magic? */ - if (memcmp(header, "scrypt", 6)) - return (7); - if (header[6] != 0) - return (8); - - /* - * Read another 89 bytes of the file; version 0 of the srypt file - * format has a 96-byte header. - */ - if (fread(&header[7], 89, 1, infile) < 1) { - if (ferror(infile)) - return (13); - else - return (7); - } - - /* Parse the header and generate derived keys. */ - if ((rc = scryptdec_setup(header, dk, passwd, passwdlen, - maxmem, maxmemfrac, maxtime)) != 0) - return (rc); - - /* Start hashing with the header. */ - HMAC_SHA256_Init(&hctx, key_hmac, 32); - HMAC_SHA256_Update(&hctx, header, 96); - - /* - * We don't know how long the encrypted data block is (we can't know, - * since data can be streamed into 'scrypt enc') so we need to read - * data and decrypt all of it except the final 32 bytes, then check - * if that final 32 bytes is the correct signature. - */ - if (AES_set_encrypt_key(key_enc, 256, &key_enc_exp)) - return (5); - if ((AES = crypto_aesctr_init(&key_enc_exp, 0)) == NULL) - return (6); - do { - /* Read data until we have more than 32 bytes of it. */ - if ((readlen = fread(&buf[buflen], 1, - ENCBLOCK + 32 - buflen, infile)) == 0) - break; - buflen += readlen; - if (buflen <= 32) - continue; - - /* - * Decrypt, hash, and output everything except the last 32 - * bytes out of what we have in our buffer. - */ - HMAC_SHA256_Update(&hctx, buf, buflen - 32); - crypto_aesctr_stream(AES, buf, buf, buflen - 32); - if (fwrite(buf, 1, buflen - 32, outfile) < buflen - 32) - return (12); - - /* Move the last 32 bytes to the start of the buffer. */ - memmove(buf, &buf[buflen - 32], 32); - buflen = 32; - } while (1); - crypto_aesctr_free(AES); - - /* Did we exit the loop due to a read error? */ - if (ferror(infile)) - return (13); - - /* Did we read enough data that we *might* have a valid signature? */ - if (buflen < 32) - return (7); - - /* Verify signature. */ - HMAC_SHA256_Final(hbuf, &hctx); - if (memcmp(hbuf, buf, 32)) - return (7); - - /* Zero sensitive data. */ - memset(dk, 0, 64); - memset(&key_enc_exp, 0, sizeof(AES_KEY)); - - return (0); -} |