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fix der encoding bug in u2f

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Conor Patrick
2018-05-26 15:35:58 -04:00
parent 9209bff54f
commit f73862ee3e
3 changed files with 31 additions and 46 deletions
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31
u2f.c
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@@ -104,33 +104,10 @@ static uint8_t get_signature_length(uint8_t * sig)
static void dump_signature_der(uint8_t * sig)
{
uint8_t pad_s = (sig[32] & 0x80) == 0x80;
uint8_t pad_r = (sig[0] & 0x80) == 0x80;
uint8_t i[] = {0x30, 0x44};
i[1] += (pad_s + pad_r);
// DER encoded signature
// write der sequence
// has to be minimum distance and padded with 0x00 if MSB is a 1.
u2f_response_writeback(i,2);
i[1] = 0;
// length of R value plus 0x00 pad if necessary
u2f_response_writeback("\x02",1);
i[0] = 0x20 + pad_r;
u2f_response_writeback(i,1 + pad_r);
// R value
u2f_response_writeback(sig, 32);
// length of S value plus 0x00 pad if necessary
u2f_response_writeback("\x02",1);
i[0] = 0x20 + pad_s;
u2f_response_writeback(i,1 + pad_s);
// S value
u2f_response_writeback(sig+32, 32);
uint8_t sigder[72];
int len;
len = ctap_encode_der_sig(sig, sigder);
u2f_response_writeback(sigder, len);
}
static int8_t u2f_load_key(struct u2f_key_handle * kh, uint8_t * appid)
{