[pkg-opensc-maint] Bug#910786: opensc: No longer recognizes Yubikey NEO after upgrade to 0.16.0-3+deb9u1

[Gianfranco Costamagna]

On Thu, 11 Oct 2018 23:32:49 +0200 Hilko Bengen <bengen at debian.org> wrote:
> Hi,
> 
> after some digging and testing, I come to the conclusion that the the
> immediate cause for the breakage I reported is the change made to the
> piv_general_io() function (src/libopensc/card-piv.c, expanded for
> context): Because rbuflen is set to zero, sc_asn1_read_tag will never
> read/parse an ASN.1 tag.
> 
> Reverting this single change seems to fix my problems, however this
> leaves the clear possibility for overflowing receive buffers that are
> passed into the function, this has so far only worked by accident...
> 
> Cheers,
> -Hilko
> 
> @@ -525,15 +525,16 @@ static int piv_general_io(sc_card_t *card, int ins, int p1, int p2,
>  	rbuflen = 0;  /* in case rseplen < 3  i.e. not parseable */
>  	if ( recvbuflen && recvbuf && apdu.resplen > 3) {
>  		*recvbuflen = 0;
>  		/* we should have all the tag data, so we have to tell sc_asn1_find_tag
>  		 * the buffer is bigger, so it will not produce "ASN1.tag too long!" */
>  
>  		body = rbuf;
> -		if (sc_asn1_read_tag(&body, 0xffff, &cla_out, &tag_out, &bodylen) !=  SC_SUCCESS) 		{
> +		if (sc_asn1_read_tag(&body, rbuflen, &cla_out, &tag_out, &bodylen) !=  SC_SUCCESS
> +				|| body == NULL)  {
>  			/* only early beta cards had this problem */
>  			sc_debug(card->ctx, SC_LOG_DEBUG_NORMAL, "***** received buffer tag MISSING ");
>  			body = rbuf;
>  			/* some readers/cards might return 6c 00 */
>  			if (apdu.sw1 == 0x61  || apdu.sw2 == 0x6c )
>  				bodylen = 12000;
>  			else
> 


I see this code changed a lot in 0.19... is this still a problem?

G.
>