[FFmpeg-devel] libavutil: Added twofish block cipher

[Michael Niedermayer]

On Thu, Jan 15, 2015 at 10:21:22PM +0530, supraja reddy wrote:
> Hello,
> 
> I have attached the patch for twofish implementation. Please let me know if
> there are any changes to be made.
> 
> Thank you,
> 
> Supraja

[...]

> +av_cold int av_twofish_init(AVTWOFISH *cs, const uint8_t *Key, int key_bits)
> +{
> +    uint32_t key[8], Ke[4], Ko[4], rh, A, B;
> +    uint8_t keypad[32];
> +    int i, j, k;
> +    k = cs->ksize = ((key_bits <=128) ? 128 : ((key_bits <=192) ? 192 : 256)) >> 6;
> +    memset(keypad, 0, sizeof(keypad));
> +    memcpy(keypad, Key, key_bits >> 3);

key_bits should be checked to be a supported value otherwise
the memcpy could write out of the array


[...]
> +#ifdef TEST
> +#include<stdio.h>
> +#include<stdlib.h>
> +#include"log.h"
> +
> +int main(int argc, char *argv[])
> +{
> +    uint8_t Key[32] = {0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10, 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff
> +    };
> +    const uint8_t rct[6][16] = {
> +        {0x9f, 0x58, 0x9f, 0x5c, 0xf6, 0x12, 0x2c, 0x32, 0xb6, 0xbf, 0xec, 0x2f, 0x2a, 0xe8, 0xc3, 0x5a},
> +        {0xcf, 0xd1, 0xd2, 0xe5, 0xa9, 0xbe, 0x9c, 0xdf, 0x50, 0x1f, 0x13, 0xb8, 0x92, 0xbd, 0x22, 0x48},
> +        {0x37, 0x52, 0x7b, 0xe0, 0x05, 0x23, 0x34, 0xb8, 0x9f, 0x0c, 0xfc, 0xca, 0xe8, 0x7c, 0xfa, 0x20},
> +        {0x5d, 0x9d, 0x4e, 0xef, 0xfa, 0x91, 0x51, 0x57, 0x55, 0x24, 0xf1, 0x15, 0x81, 0x5a, 0x12, 0xe0},
> +        {0xe7, 0x54, 0x49, 0x21, 0x2b, 0xee, 0xf9, 0xf4, 0xa3, 0x90, 0xbd, 0x86, 0x0a, 0x64, 0x09, 0x41},
> +        {0x37, 0xfe, 0x26, 0xff, 0x1c, 0xf6, 0x61, 0x75, 0xf5, 0xdd, 0xf4, 0xc3, 0x3b, 0x97, 0xa2, 0x05}
> +    };
> +    uint8_t temp[32], iv[16], rpt[32];
> +    const int kbits[3] = {128, 192, 256};
> +    int i, j, err = 0;
> +    AVTWOFISH *cs;
> +    cs = av_twofish_alloc();
> +    if (!cs)
> +        return 1;

> +    memset(rpt, 0, sizeof(rpt));

could be avoided with:
uint8_t rpt[32] = {0};

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

There will always be a question for which you do not know the correct answer.
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