Smart Card Minidriver

An out-of-bounds read issue was discovered in the Yubico-Piv 1.5.0 smartcard driver. The file lib/ykpiv.c contains the following code in the function `_ykpiv_fetch_object()`: {% highlight c %} if(sw == SW_SUCCESS) { size_t outlen; int offs = _ykpiv_get_length(data + 1, &outlen); if(offs == 0) { return YKPIV_SIZE_ERROR; } memmove(data, data + 1 + offs, outlen); *len = outlen; return YKPIV_OK; } else { return YKPIV_GENERIC_ERROR; } {% endhighlight %} -- in the end, a `memmove()` occurs with a length retrieved from APDU data. This length is not checked for whether it is outside of the APDU data retrieved. Therefore the `memmove()` could copy bytes behind the allocated data buffer into this buffer.

Published: 2018-08-15T18:00:00.000Z
Updated: 2024-08-05T09:38:13.975Z

A buffer overflow issue was discovered in the Yubico-Piv 1.5.0 smartcard driver. The file lib/ykpiv.c contains the following code in the function `ykpiv_transfer_data()`: {% highlight c %} if(*out_len + recv_len - 2 > max_out) { fprintf(stderr, "Output buffer to small, wanted to write %lu, max was %lu.", *out_len + recv_len - 2, max_out); } if(out_data) { memcpy(out_data, data, recv_len - 2); out_data += recv_len - 2; *out_len += recv_len - 2; } {% endhighlight %} -- it is clearly checked whether the buffer is big enough to hold the data copied using `memcpy()`, but no error handling happens to avoid the `memcpy()` in such cases. This code path can be triggered with malicious data coming from a smartcard.

Published: 2018-08-15T18:00:00.000Z
Updated: 2024-08-05T09:38:13.960Z