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Fail if block to encrypt ends up being less than one full block for now, and tidy up code.

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This commit is contained in:
Con Kolivas 2011-03-16 23:13:09 +11:00
parent c41cfe9e83
commit a7468ce6e4
1 changed files with 23 additions and 14 deletions
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37
stream.c
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@ -1169,22 +1169,29 @@ retry:
} }
if (!ret && ENCRYPT) { if (!ret && ENCRYPT) {
/* Encryption requires CBC_LEN blocks so we can use ciphertext
* stealing to not have to pad the block */
unsigned char ivec[CBC_LEN], tmp0[CBC_LEN], tmp1[CBC_LEN]; unsigned char ivec[CBC_LEN], tmp0[CBC_LEN], tmp1[CBC_LEN];
i64 N, M; i64 N, M;
memcpy (ivec, control->hash_iv, sizeof(ivec)); if (unlikely(cti->c_len < CBC_LEN))
failure("Unable to encrypt when compressed blocks end up being less than %d bytes, this one being %lld\n",
CBC_LEN, cti->c_len);
memcpy(ivec, control->hash_iv, sizeof(ivec));
M = cti->c_len % CBC_LEN; M = cti->c_len % CBC_LEN;
N = cti->c_len - M; N = cti->c_len - M;
print_maxverbose("Encrypting block \n"); print_maxverbose("Encrypting block \n");
aes_crypt_cbc(&control->aes_ctx, AES_ENCRYPT, N, ivec, cti->s_buf, cti->s_buf); aes_crypt_cbc(&control->aes_ctx, AES_ENCRYPT, N, ivec,
cti->s_buf, cti->s_buf);
if (M) { if (M) {
memset(tmp0, 0, sizeof(tmp0)); memset(tmp0, 0, sizeof(tmp0));
memcpy(tmp0, cti->s_buf + N, M); memcpy(tmp0, cti->s_buf + N, M);
aes_crypt_cbc(&control->aes_ctx, AES_ENCRYPT, CBC_LEN, ivec, tmp0, tmp1); aes_crypt_cbc(&control->aes_ctx, AES_ENCRYPT, CBC_LEN,
memcpy (cti->s_buf + N, cti->s_buf + N - CBC_LEN, M); ivec, tmp0, tmp1);
memcpy (cti->s_buf + N - CBC_LEN, tmp1, CBC_LEN); memcpy(cti->s_buf + N, cti->s_buf + N - CBC_LEN, M);
memcpy(cti->s_buf + N - CBC_LEN, tmp1, CBC_LEN);
} }
} }
@ -1443,7 +1450,7 @@ fill_another:
unsigned char ivec[CBC_LEN], tmp0[CBC_LEN], tmp1[CBC_LEN]; unsigned char ivec[CBC_LEN], tmp0[CBC_LEN], tmp1[CBC_LEN];
i64 N, M; i64 N, M;
memcpy (ivec, control->hash_iv, sizeof(ivec)); memcpy(ivec, control->hash_iv, sizeof(ivec));
M = c_len % CBC_LEN; M = c_len % CBC_LEN;
N = c_len - M; N = c_len - M;
@ -1451,14 +1458,16 @@ fill_another:
if (M) { if (M) {
aes_crypt_cbc(&control->aes_ctx, AES_DECRYPT, N - CBC_LEN, aes_crypt_cbc(&control->aes_ctx, AES_DECRYPT, N - CBC_LEN,
ivec, s_buf, s_buf); ivec, s_buf, s_buf);
aes_crypt_ecb(&control->aes_ctx, AES_DECRYPT, s_buf + N - CBC_LEN, tmp0); aes_crypt_ecb(&control->aes_ctx, AES_DECRYPT,
memset (tmp1, 0, CBC_LEN); s_buf + N - CBC_LEN, tmp0);
memcpy (tmp1, s_buf + N, M); memset(tmp1, 0, CBC_LEN);
xor128 (tmp0, tmp1); memcpy(tmp1, s_buf + N, M);
memcpy (s_buf + N, tmp0, M); xor128(tmp0, tmp1);
memcpy (tmp1 + M, tmp0 + M, CBC_LEN - M); memcpy(s_buf + N, tmp0, M);
aes_crypt_ecb(&control->aes_ctx, AES_DECRYPT, tmp1, s_buf + N - CBC_LEN); memcpy(tmp1 + M, tmp0 + M, CBC_LEN - M);
xor128 (s_buf + N - CBC_LEN, ivec); aes_crypt_ecb(&control->aes_ctx, AES_DECRYPT, tmp1,
s_buf + N - CBC_LEN);
xor128(s_buf + N - CBC_LEN, ivec);
} else } else
aes_crypt_cbc(&control->aes_ctx, AES_DECRYPT, c_len, aes_crypt_cbc(&control->aes_ctx, AES_DECRYPT, c_len,
ivec, s_buf, s_buf); ivec, s_buf, s_buf);