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Re: [Qemu-devel] [PATCH] crypto: assert cipher algorithm is always valid
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-devel] [PATCH] crypto: assert cipher algorithm is always valid |
Date: |
Mon, 20 Feb 2017 11:40:29 +0000 |
User-agent: |
Mutt/1.7.1 (2016-10-04) |
On Mon, Feb 20, 2017 at 04:53:07PM +0530, P J P wrote:
> From: Prasad J Pandit <address@hidden>
>
> Crypto routines 'qcrypto_cipher_get_block_len' and
> 'qcrypto_cipher_get_key_len' return non-zero cipher block and key
> lengths from static arrays 'alg_block_len[]' and 'alg_key_len[]'
> respectively. Returning 'zero(0)' value from either of them would
> likely lead to an error condition.
Well callers are supposed to check for 0 condition and report an
error really. In practice none of them do, and the alg parameters
they pass in all come from constants. So we're not validating user
input here - we're catching programming bugs and thus assert makes
sense.
>
> Signed-off-by: Prasad J Pandit <address@hidden>
> ---
> crypto/cipher.c | 8 ++------
> 1 file changed, 2 insertions(+), 6 deletions(-)
Reviewed-by: Daniel P. Berrange <address@hidden>
>
> diff --git a/crypto/cipher.c b/crypto/cipher.c
> index 9ecaff7..5a96489 100644
> --- a/crypto/cipher.c
> +++ b/crypto/cipher.c
> @@ -63,18 +63,14 @@ static bool mode_need_iv[QCRYPTO_CIPHER_MODE__MAX] = {
>
> size_t qcrypto_cipher_get_block_len(QCryptoCipherAlgorithm alg)
> {
> - if (alg >= G_N_ELEMENTS(alg_key_len)) {
> - return 0;
> - }
> + assert(alg < G_N_ELEMENTS(alg_key_len));
> return alg_block_len[alg];
> }
>
>
> size_t qcrypto_cipher_get_key_len(QCryptoCipherAlgorithm alg)
> {
> - if (alg >= G_N_ELEMENTS(alg_key_len)) {
> - return 0;
> - }
> + assert(alg < G_N_ELEMENTS(alg_key_len));
> return alg_key_len[alg];
> }
Adding to the crypto/ queue
Regards,
Daniel
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