Commit 17295884 authored by Richard Levitte's avatar Richard Levitte
Browse files

The AES CTR API was buggy, we need to save the encrypted counter as well 

between calls, or that will be lost if it returned with *num non-zero.
parent 6f7c2cb3

crypto/aes/aes.h

+3 −1
Original line number Diff line number Diff line
@@ -99,7 +99,9 @@ void AES_ofb128_encrypt(const unsigned char *in, unsigned char *out, 
	unsigned char *ivec, int *num);

void AES_ctr128_encrypt(const unsigned char *in, unsigned char *out,

	const unsigned long length, const AES_KEY *key,

	unsigned char *counter, unsigned int *num);

	unsigned char counter[AES_BLOCK_SIZE],

	unsigned char ecount_buf[AES_BLOCK_SIZE],

	unsigned int *num);





#ifdef  __cplusplus

crypto/aes/aes_ctr.c

+5 −4
Original line number Diff line number Diff line
@@ -94,11 +94,12 @@ static void AES_ctr128_inc(unsigned char *counter) { 
 */

void AES_ctr128_encrypt(const unsigned char *in, unsigned char *out,

	const unsigned long length, const AES_KEY *key,

	unsigned char *counter, unsigned int *num) {

	unsigned char counter[AES_BLOCK_SIZE],

	unsigned char ecount_buf[AES_BLOCK_SIZE],

	unsigned int *num) {



	unsigned int n;

	unsigned long l=length;

	unsigned char tmp[AES_BLOCK_SIZE];



	assert(in && out && key && counter && num);
@@ -106,10 +107,10 @@ void AES_ctr128_encrypt(const unsigned char *in, unsigned char *out, 


	while (l--) {

		if (n == 0) {

			AES_encrypt(counter, tmp, key);

			AES_encrypt(counter, ecount_buf, key);

			AES_ctr128_inc(counter);

		}

		*(out++) = *(in++) ^ tmp[n];

		*(out++) = *(in++) ^ ecount_buf[n];

		n = (n+1) % AES_BLOCK_SIZE;

	}