diff options
Diffstat (limited to 'src/lib/crypto/enc_provider/aes.c')
| -rw-r--r-- | src/lib/crypto/enc_provider/aes.c | 83 |
1 files changed, 56 insertions, 27 deletions
diff --git a/src/lib/crypto/enc_provider/aes.c b/src/lib/crypto/enc_provider/aes.c index d3dc2a5..1fc7abc 100644 --- a/src/lib/crypto/enc_provider/aes.c +++ b/src/lib/crypto/enc_provider/aes.c @@ -52,23 +52,8 @@ static void printd (const char *descr, krb5_data *d) { } printf("\n"); } -static void enc(char *out, const char *in, aes_ctx *ctx) -{ - if (aes_enc_blk(in, out, ctx) != aes_good) - abort(); -#if 0 - { - krb5_data e_in, e_out; - e_in.data = in; - e_out.data = out; - e_in.length = e_out.length = BLOCK_SIZE; - printf("encrypting [[\n"); - printd("input block", &e_in); - printd("output block", &e_out); - printf("]]\n"); - } -#endif -} +#define enc(OUT, IN, CTX) (aes_enc_blk((IN),(OUT),(CTX)) == aes_good ? (void) 0 : abort()) +#define dec(OUT, IN, CTX) (aes_dec_blk((IN),(OUT),(CTX)) == aes_good ? (void) 0 : abort()) static void xorblock(char *out, const char *in) { @@ -83,7 +68,6 @@ krb5int_aes_encrypt(const krb5_keyblock *key, const krb5_data *ivec, { aes_ctx ctx; unsigned char tmp[BLOCK_SIZE], tmp2[BLOCK_SIZE], tmp3[BLOCK_SIZE]; - int offset; int nblocks = 0, blockno; /* CHECK_SIZES; */ @@ -100,8 +84,7 @@ krb5int_aes_encrypt(const krb5_keyblock *key, const krb5_data *ivec, if (nblocks == 1) { /* XXX Used for DK function. */ - if (aes_enc_blk(input->data, output->data, &ctx) != aes_good) - abort(); + enc(output->data, input->data, &ctx); } else { int nleft; @@ -112,7 +95,6 @@ krb5int_aes_encrypt(const krb5_keyblock *key, const krb5_data *ivec, /* Set up for next block. */ memcpy(tmp, tmp2, BLOCK_SIZE); - offset += BLOCK_SIZE; } /* Do final CTS step for last two blocks (the second of which may or may not be incomplete). */ @@ -127,23 +109,70 @@ krb5int_aes_encrypt(const krb5_keyblock *key, const krb5_data *ivec, xorblock(tmp, tmp3); enc(tmp2, tmp, &ctx); memcpy(output->data + (nblocks - 2) * BLOCK_SIZE, tmp2, BLOCK_SIZE); + if (ivec) + memcpy(ivec->data, tmp2, BLOCK_SIZE); } return 0; } -static krb5_error_code -k5_aes_decrypt(const krb5_keyblock *key, const krb5_data *ivec, - const krb5_data *input, krb5_data *output) +krb5_error_code +krb5int_aes_decrypt(const krb5_keyblock *key, const krb5_data *ivec, + const krb5_data *input, krb5_data *output) { aes_ctx ctx; + unsigned char tmp[BLOCK_SIZE], tmp2[BLOCK_SIZE], tmp3[BLOCK_SIZE]; + int nblocks = 0, blockno; CHECK_SIZES; if (aes_dec_key(key->contents, key->length, &ctx) != aes_good) abort(); - abort(); + if (ivec) + memcpy(tmp, ivec->data, BLOCK_SIZE); + else + memset(tmp, 0, BLOCK_SIZE); + + nblocks = (input->length + BLOCK_SIZE - 1) / BLOCK_SIZE; + + if (nblocks == 1) { + if (input->length < BLOCK_SIZE) + abort(); + dec(output->data, input->data, &ctx); + } else { + int nleft; + + for (blockno = 0; blockno < nblocks - 2; blockno++) { + dec(tmp2, input->data + blockno * BLOCK_SIZE, &ctx); + xorblock(tmp2, tmp); + memcpy(output->data + blockno * BLOCK_SIZE, tmp2, BLOCK_SIZE); + memcpy(tmp, input->data + blockno * BLOCK_SIZE, BLOCK_SIZE); + } + /* Do last two blocks, the second of which (next-to-last block + of plaintext) may be incomplete. */ + dec(tmp2, input->data + (nblocks - 2) * BLOCK_SIZE, &ctx); + /* Set tmp3 to last ciphertext block, padded. */ + memset(tmp3, 0, sizeof(tmp3)); + memcpy(tmp3, input->data + (nblocks - 1) * BLOCK_SIZE, + input->length - (nblocks - 1) * BLOCK_SIZE); + /* Set tmp2 to last (possibly partial) plaintext block, and + save it. */ + xorblock(tmp2, tmp3); + memcpy(output->data + (nblocks - 1) * BLOCK_SIZE, tmp2, + input->length - (nblocks - 1) * BLOCK_SIZE); + /* Maybe keep the trailing part, and copy in the last + ciphertext block. */ + memcpy(tmp2, tmp3, input->length - (nblocks - 1) * BLOCK_SIZE); + /* Decrypt, to get next to last plaintext block xor previous + ciphertext. */ + dec(tmp3, tmp2, &ctx); + xorblock(tmp3, tmp); + memcpy(output->data + (nblocks - 2) * BLOCK_SIZE, tmp3, BLOCK_SIZE); + if (ivec) + memcpy(ivec->data, input->data + (nblocks - 2) * BLOCK_SIZE, + BLOCK_SIZE); + } return 0; } @@ -178,7 +207,7 @@ const struct krb5_enc_provider krb5int_enc_aes128 = { aes_block_size, aes128_keysize, krb5int_aes_encrypt, - k5_aes_decrypt, + krb5int_aes_decrypt, k5_aes_make_key, krb5int_aes_init_state, krb5int_default_free_state @@ -188,7 +217,7 @@ const struct krb5_enc_provider krb5int_enc_aes256 = { aes_block_size, aes256_keysize, krb5int_aes_encrypt, - k5_aes_decrypt, + krb5int_aes_decrypt, k5_aes_make_key, krb5int_aes_init_state, krb5int_default_free_state |