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crypto: add sanity checking of plaintext/ciphertext length

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When encrypting/decrypting data, the plaintext/ciphertext
buffers are required to be a multiple of the cipher block
size. If this is not done, nettle will abort and gcrypt
will report an error. To get consistent behaviour add
explicit checks upfront for the buffer sizes.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
This commit is contained in:
Daniel P. Berrange 2015-10-16 16:35:06 +01:00
parent eb2a770b17
commit 3a661f1eab
4 changed files with 130 additions and 24 deletions
Download patch file Download diff file Expand all files Collapse all files

15
crypto/cipher-builtin.c
View file

@ -39,6 +39,7 @@ struct QCryptoCipherBuiltin {
QCryptoCipherBuiltinAES aes;
QCryptoCipherBuiltinDESRFB desrfb;
} state;
size_t blocksize;
void (*free)(QCryptoCipher *cipher);
int (*setiv)(QCryptoCipher *cipher,
const uint8_t *iv, size_t niv,
@ -181,6 +182,7 @@ static int qcrypto_cipher_init_aes(QCryptoCipher *cipher,
goto error;
}
ctxt->blocksize = AES_BLOCK_SIZE;
ctxt->free = qcrypto_cipher_free_aes;
ctxt->setiv = qcrypto_cipher_setiv_aes;
ctxt->encrypt = qcrypto_cipher_encrypt_aes;
@ -282,6 +284,7 @@ static int qcrypto_cipher_init_des_rfb(QCryptoCipher *cipher,
memcpy(ctxt->state.desrfb.key, key, nkey);
ctxt->state.desrfb.nkey = nkey;
ctxt->blocksize = 8;
ctxt->free = qcrypto_cipher_free_des_rfb;
ctxt->setiv = qcrypto_cipher_setiv_des_rfb;
ctxt->encrypt = qcrypto_cipher_encrypt_des_rfb;
@ -370,6 +373,12 @@ int qcrypto_cipher_encrypt(QCryptoCipher *cipher,
{
QCryptoCipherBuiltin *ctxt = cipher->opaque;
if (len % ctxt->blocksize) {
error_setg(errp, "Length %zu must be a multiple of block size %zu",
len, ctxt->blocksize);
return -1;
}
return ctxt->encrypt(cipher, in, out, len, errp);
}
@ -382,6 +391,12 @@ int qcrypto_cipher_decrypt(QCryptoCipher *cipher,
{
QCryptoCipherBuiltin *ctxt = cipher->opaque;
if (len % ctxt->blocksize) {
error_setg(errp, "Length %zu must be a multiple of block size %zu",
len, ctxt->blocksize);
return -1;
}
return ctxt->decrypt(cipher, in, out, len, errp);
}