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Diffstat (limited to 'contrib/pgcrypto/pgp-cfb.c')
| -rw-r--r-- | contrib/pgcrypto/pgp-cfb.c | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/contrib/pgcrypto/pgp-cfb.c b/contrib/pgcrypto/pgp-cfb.c new file mode 100644 index 0000000..dafa562 --- /dev/null +++ b/contrib/pgcrypto/pgp-cfb.c @@ -0,0 +1,263 @@ +/* + * pgp-cfb.c + * Implements both normal and PGP-specific CFB mode. + * + * Copyright (c) 2005 Marko Kreen + * 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. + * + * contrib/pgcrypto/pgp-cfb.c + */ + +#include "postgres.h" + +#include "pgp.h" +#include "px.h" + +typedef int (*mix_data_t) (PGP_CFB *ctx, const uint8 *data, int len, uint8 *dst); + +struct PGP_CFB +{ + PX_Cipher *ciph; + int block_size; + int pos; + int block_no; + int resync; + uint8 fr[PGP_MAX_BLOCK]; + uint8 fre[PGP_MAX_BLOCK]; + uint8 encbuf[PGP_MAX_BLOCK]; +}; + +int +pgp_cfb_create(PGP_CFB **ctx_p, int algo, const uint8 *key, int key_len, + int resync, uint8 *iv) +{ + int res; + PX_Cipher *ciph; + PGP_CFB *ctx; + + res = pgp_load_cipher(algo, &ciph); + if (res < 0) + return res; + + res = px_cipher_init(ciph, key, key_len, NULL); + if (res < 0) + { + px_cipher_free(ciph); + return res; + } + + ctx = palloc0(sizeof(*ctx)); + ctx->ciph = ciph; + ctx->block_size = px_cipher_block_size(ciph); + ctx->resync = resync; + + if (iv) + memcpy(ctx->fr, iv, ctx->block_size); + + *ctx_p = ctx; + return 0; +} + +void +pgp_cfb_free(PGP_CFB *ctx) +{ + px_cipher_free(ctx->ciph); + px_memset(ctx, 0, sizeof(*ctx)); + pfree(ctx); +} + +/* + * Data processing for normal CFB. (PGP_PKT_SYMENCRYPTED_DATA_MDC) + */ +static int +mix_encrypt_normal(PGP_CFB *ctx, const uint8 *data, int len, uint8 *dst) +{ + int i; + + for (i = ctx->pos; i < ctx->pos + len; i++) + *dst++ = ctx->encbuf[i] = ctx->fre[i] ^ (*data++); + ctx->pos += len; + return len; +} + +static int +mix_decrypt_normal(PGP_CFB *ctx, const uint8 *data, int len, uint8 *dst) +{ + int i; + + for (i = ctx->pos; i < ctx->pos + len; i++) + { + ctx->encbuf[i] = *data++; + *dst++ = ctx->fre[i] ^ ctx->encbuf[i]; + } + ctx->pos += len; + return len; +} + +/* + * Data processing for old PGP CFB mode. (PGP_PKT_SYMENCRYPTED_DATA) + * + * The goal is to hide the horror from the rest of the code, + * thus its all concentrated here. + */ +static int +mix_encrypt_resync(PGP_CFB *ctx, const uint8 *data, int len, uint8 *dst) +{ + int i, + n; + + /* block #2 is 2 bytes long */ + if (ctx->block_no == 2) + { + n = 2 - ctx->pos; + if (len < n) + n = len; + for (i = ctx->pos; i < ctx->pos + n; i++) + *dst++ = ctx->encbuf[i] = ctx->fre[i] ^ (*data++); + + ctx->pos += n; + len -= n; + + if (ctx->pos == 2) + { + memcpy(ctx->fr, ctx->encbuf + 2, ctx->block_size - 2); + memcpy(ctx->fr + ctx->block_size - 2, ctx->encbuf, 2); + ctx->pos = 0; + return n; + } + } + for (i = ctx->pos; i < ctx->pos + len; i++) + *dst++ = ctx->encbuf[i] = ctx->fre[i] ^ (*data++); + ctx->pos += len; + return len; +} + +static int +mix_decrypt_resync(PGP_CFB *ctx, const uint8 *data, int len, uint8 *dst) +{ + int i, + n; + + /* block #2 is 2 bytes long */ + if (ctx->block_no == 2) + { + n = 2 - ctx->pos; + if (len < n) + n = len; + for (i = ctx->pos; i < ctx->pos + n; i++) + { + ctx->encbuf[i] = *data++; + *dst++ = ctx->fre[i] ^ ctx->encbuf[i]; + } + ctx->pos += n; + len -= n; + + if (ctx->pos == 2) + { + memcpy(ctx->fr, ctx->encbuf + 2, ctx->block_size - 2); + memcpy(ctx->fr + ctx->block_size - 2, ctx->encbuf, 2); + ctx->pos = 0; + return n; + } + } + for (i = ctx->pos; i < ctx->pos + len; i++) + { + ctx->encbuf[i] = *data++; + *dst++ = ctx->fre[i] ^ ctx->encbuf[i]; + } + ctx->pos += len; + return len; +} + +/* + * common code for both encrypt and decrypt. + */ +static int +cfb_process(PGP_CFB *ctx, const uint8 *data, int len, uint8 *dst, + mix_data_t mix_data) +{ + int n; + int res; + + while (len > 0 && ctx->pos > 0) + { + n = ctx->block_size - ctx->pos; + if (len < n) + n = len; + + n = mix_data(ctx, data, n, dst); + data += n; + dst += n; + len -= n; + + if (ctx->pos == ctx->block_size) + { + memcpy(ctx->fr, ctx->encbuf, ctx->block_size); + ctx->pos = 0; + } + } + + while (len > 0) + { + px_cipher_encrypt(ctx->ciph, ctx->fr, ctx->block_size, ctx->fre); + if (ctx->block_no < 5) + ctx->block_no++; + + n = ctx->block_size; + if (len < n) + n = len; + + res = mix_data(ctx, data, n, dst); + data += res; + dst += res; + len -= res; + + if (ctx->pos == ctx->block_size) + { + memcpy(ctx->fr, ctx->encbuf, ctx->block_size); + ctx->pos = 0; + } + } + return 0; +} + +/* + * public interface + */ + +int +pgp_cfb_encrypt(PGP_CFB *ctx, const uint8 *data, int len, uint8 *dst) +{ + mix_data_t mix = ctx->resync ? mix_encrypt_resync : mix_encrypt_normal; + + return cfb_process(ctx, data, len, dst, mix); +} + +int +pgp_cfb_decrypt(PGP_CFB *ctx, const uint8 *data, int len, uint8 *dst) +{ + mix_data_t mix = ctx->resync ? mix_decrypt_resync : mix_decrypt_normal; + + return cfb_process(ctx, data, len, dst, mix); +} |