diff options
Diffstat (limited to 'smtpd/crypto.c')
| -rw-r--r-- | smtpd/crypto.c | 400 |
1 files changed, 0 insertions, 400 deletions
diff --git a/smtpd/crypto.c b/smtpd/crypto.c deleted file mode 100644 index 20a422cd..00000000 --- a/smtpd/crypto.c +++ /dev/null @@ -1,400 +0,0 @@ -/* $OpenBSD: crypto.c,v 1.8 2019/06/28 13:32:50 deraadt Exp $ */ - -/* - * Copyright (c) 2013 Gilles Chehade <gilles@openbsd.org> - * - * Permission to use, copy, modify, and distribute this software for any - * purpose with or without fee is hereby granted, provided that the above - * copyright notice and this permission notice appear in all copies. - * - * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES - * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF - * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR - * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES - * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN - * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF - * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. - */ - -#include "includes.h" - -#include <sys/types.h> -#include <sys/stat.h> - -#include <stdlib.h> -#include <string.h> - -#include <openssl/evp.h> - - -#define CRYPTO_BUFFER_SIZE 16384 - -#define GCM_TAG_SIZE 16 -#define IV_SIZE 12 -#define KEY_SIZE 32 - -/* bump if we ever switch from aes-256-gcm to anything else */ -#define API_VERSION 1 - - -int crypto_setup(const char *, size_t); -int crypto_encrypt_file(FILE *, FILE *); -int crypto_decrypt_file(FILE *, FILE *); -size_t crypto_encrypt_buffer(const char *, size_t, char *, size_t); -size_t crypto_decrypt_buffer(const char *, size_t, char *, size_t); - -static struct crypto_ctx { - unsigned char key[KEY_SIZE]; -} cp; - -int -crypto_setup(const char *key, size_t len) -{ - if (len != KEY_SIZE) - return 0; - - memset(&cp, 0, sizeof cp); - - /* openssl rand -hex 16 */ - memcpy(cp.key, key, sizeof cp.key); - - return 1; -} - -int -crypto_encrypt_file(FILE * in, FILE * out) -{ - EVP_CIPHER_CTX *ctx; - uint8_t ibuf[CRYPTO_BUFFER_SIZE]; - uint8_t obuf[CRYPTO_BUFFER_SIZE]; - uint8_t iv[IV_SIZE]; - uint8_t tag[GCM_TAG_SIZE]; - uint8_t version = API_VERSION; - size_t r, w; - int len; - int ret = 0; - struct stat sb; - - /* XXX - Do NOT encrypt files bigger than 64GB */ - if (fstat(fileno(in), &sb) == -1) - return 0; - if (sb.st_size >= 0x1000000000LL) - return 0; - - /* prepend version byte*/ - if ((w = fwrite(&version, 1, sizeof version, out)) != sizeof version) - return 0; - - /* generate and prepend IV */ - memset(iv, 0, sizeof iv); - arc4random_buf(iv, sizeof iv); - if ((w = fwrite(iv, 1, sizeof iv, out)) != sizeof iv) - return 0; - - ctx = EVP_CIPHER_CTX_new(); - if (ctx == NULL) - return 0; - - EVP_EncryptInit_ex(ctx, EVP_aes_256_gcm(), NULL, cp.key, iv); - - /* encrypt until end of file */ - while ((r = fread(ibuf, 1, CRYPTO_BUFFER_SIZE, in)) != 0) { - if (!EVP_EncryptUpdate(ctx, obuf, &len, ibuf, r)) - goto end; - if (len && (w = fwrite(obuf, len, 1, out)) != 1) - goto end; - } - if (!feof(in)) - goto end; - - /* finalize and write last chunk if any */ - if (!EVP_EncryptFinal_ex(ctx, obuf, &len)) - goto end; - if (len && (w = fwrite(obuf, len, 1, out)) != 1) - goto end; - - /* get and append tag */ - EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_GET_TAG, sizeof tag, tag); - if ((w = fwrite(tag, sizeof tag, 1, out)) != 1) - goto end; - - fflush(out); - ret = 1; - -end: - EVP_CIPHER_CTX_free(ctx); - return ret; -} - -int -crypto_decrypt_file(FILE * in, FILE * out) -{ - EVP_CIPHER_CTX *ctx; - uint8_t ibuf[CRYPTO_BUFFER_SIZE]; - uint8_t obuf[CRYPTO_BUFFER_SIZE]; - uint8_t iv[IV_SIZE]; - uint8_t tag[GCM_TAG_SIZE]; - uint8_t version; - size_t r, w; - off_t sz; - int len; - int ret = 0; - struct stat sb; - - /* input file too small to be an encrypted file */ - if (fstat(fileno(in), &sb) == -1) - return 0; - if (sb.st_size <= (off_t) (sizeof version + sizeof tag + sizeof iv)) - return 0; - sz = sb.st_size; - - /* extract tag */ - if (fseek(in, -sizeof(tag), SEEK_END) == -1) - return 0; - if ((r = fread(tag, 1, sizeof tag, in)) != sizeof tag) - return 0; - - if (fseek(in, 0, SEEK_SET) == -1) - return 0; - - /* extract version */ - if ((r = fread(&version, 1, sizeof version, in)) != sizeof version) - return 0; - if (version != API_VERSION) - return 0; - - /* extract IV */ - memset(iv, 0, sizeof iv); - if ((r = fread(iv, 1, sizeof iv, in)) != sizeof iv) - return 0; - - /* real ciphertext length */ - sz -= sizeof version; - sz -= sizeof iv; - sz -= sizeof tag; - - ctx = EVP_CIPHER_CTX_new(); - if (ctx == NULL) - return 0; - - EVP_DecryptInit_ex(ctx, EVP_aes_256_gcm(), NULL, cp.key, iv); - - /* set expected tag */ - EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_TAG, sizeof tag, tag); - - /* decrypt until end of ciphertext */ - while (sz) { - if (sz > CRYPTO_BUFFER_SIZE) - r = fread(ibuf, 1, CRYPTO_BUFFER_SIZE, in); - else - r = fread(ibuf, 1, sz, in); - if (!r) - break; - if (!EVP_DecryptUpdate(ctx, obuf, &len, ibuf, r)) - goto end; - if (len && (w = fwrite(obuf, len, 1, out)) != 1) - goto end; - sz -= r; - } - if (ferror(in)) - goto end; - - /* finalize, write last chunk if any and perform authentication check */ - if (!EVP_DecryptFinal_ex(ctx, obuf, &len)) - goto end; - if (len && (w = fwrite(obuf, len, 1, out)) != 1) - goto end; - - fflush(out); - ret = 1; - -end: - EVP_CIPHER_CTX_free(ctx); - return ret; -} - -size_t -crypto_encrypt_buffer(const char *in, size_t inlen, char *out, size_t outlen) -{ - EVP_CIPHER_CTX *ctx; - uint8_t iv[IV_SIZE]; - uint8_t tag[GCM_TAG_SIZE]; - uint8_t version = API_VERSION; - off_t sz; - int olen; - int len = 0; - int ret = 0; - - /* output buffer does not have enough room */ - if (outlen < inlen + sizeof version + sizeof tag + sizeof iv) - return 0; - - /* input should not exceed 64GB */ - sz = inlen; - if (sz >= 0x1000000000LL) - return 0; - - /* prepend version */ - *out = version; - len++; - - /* generate IV */ - memset(iv, 0, sizeof iv); - arc4random_buf(iv, sizeof iv); - memcpy(out + len, iv, sizeof iv); - len += sizeof iv; - - ctx = EVP_CIPHER_CTX_new(); - if (ctx == NULL) - return 0; - - EVP_EncryptInit_ex(ctx, EVP_aes_256_gcm(), NULL, cp.key, iv); - - /* encrypt buffer */ - if (!EVP_EncryptUpdate(ctx, out + len, &olen, in, inlen)) - goto end; - len += olen; - - /* finalize and write last chunk if any */ - if (!EVP_EncryptFinal_ex(ctx, out + len, &olen)) - goto end; - len += olen; - - /* get and append tag */ - EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_GET_TAG, sizeof tag, tag); - memcpy(out + len, tag, sizeof tag); - ret = len + sizeof tag; - -end: - EVP_CIPHER_CTX_free(ctx); - return ret; -} - -size_t -crypto_decrypt_buffer(const char *in, size_t inlen, char *out, size_t outlen) -{ - EVP_CIPHER_CTX *ctx; - uint8_t iv[IV_SIZE]; - uint8_t tag[GCM_TAG_SIZE]; - int olen; - int len = 0; - int ret = 0; - - /* out does not have enough room */ - if (outlen < inlen - sizeof tag + sizeof iv) - return 0; - - /* extract tag */ - memcpy(tag, in + inlen - sizeof tag, sizeof tag); - inlen -= sizeof tag; - - /* check version */ - if (*in != API_VERSION) - return 0; - in++; - inlen--; - - /* extract IV */ - memset(iv, 0, sizeof iv); - memcpy(iv, in, sizeof iv); - inlen -= sizeof iv; - in += sizeof iv; - - ctx = EVP_CIPHER_CTX_new(); - if (ctx == NULL) - return 0; - - EVP_DecryptInit_ex(ctx, EVP_aes_256_gcm(), NULL, cp.key, iv); - - /* set expected tag */ - EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_SET_TAG, sizeof tag, tag); - - /* decrypt buffer */ - if (!EVP_DecryptUpdate(ctx, out, &olen, in, inlen)) - goto end; - len += olen; - - /* finalize, write last chunk if any and perform authentication check */ - if (!EVP_DecryptFinal_ex(ctx, out + len, &olen)) - goto end; - ret = len + olen; - -end: - EVP_CIPHER_CTX_free(ctx); - return ret; -} - -#if 0 -int -main(int argc, char *argv[]) -{ - if (argc != 3) { - printf("usage: crypto <key> <buffer>\n"); - return 1; - } - - if (!crypto_setup(argv[1], strlen(argv[1]))) { - printf("crypto_setup failed\n"); - return 1; - } - - { - char encbuffer[4096]; - size_t enclen; - char decbuffer[4096]; - size_t declen; - - printf("encrypt/decrypt buffer: "); - enclen = crypto_encrypt_buffer(argv[2], strlen(argv[2]), - encbuffer, sizeof encbuffer); - - /* uncomment below to provoke integrity check failure */ - /* - * encbuffer[13] = 0x42; - * encbuffer[14] = 0x42; - * encbuffer[15] = 0x42; - * encbuffer[16] = 0x42; - */ - - declen = crypto_decrypt_buffer(encbuffer, enclen, - decbuffer, sizeof decbuffer); - if (declen != 0 && !strncmp(argv[2], decbuffer, declen)) - printf("ok\n"); - else - printf("nope\n"); - } - - { - FILE *fpin; - FILE *fpout; - printf("encrypt/decrypt file: "); - - fpin = fopen("/etc/passwd", "r"); - fpout = fopen("/tmp/passwd.enc", "w"); - if (!crypto_encrypt_file(fpin, fpout)) { - printf("encryption failed\n"); - return 1; - } - fclose(fpin); - fclose(fpout); - - /* uncomment below to provoke integrity check failure */ - /* - * fpin = fopen("/tmp/passwd.enc", "a"); - * fprintf(fpin, "borken"); - * fclose(fpin); - */ - fpin = fopen("/tmp/passwd.enc", "r"); - fpout = fopen("/tmp/passwd.dec", "w"); - if (!crypto_decrypt_file(fpin, fpout)) - printf("nope\n"); - else - printf("ok\n"); - fclose(fpin); - fclose(fpout); - } - - - return 0; -} -#endif |