On 12/7/2012 5:15 PM, Frank Morgner wrote:
> Hi!
>
> Currently, sc_check_apdu checks the length of an R-APDU buffer using
> SC_MAX_APDU_BUFFER_SIZE, which defines the maximum length for a C-APDU.
> https://github.com/OpenSC/OpenSC/blob/master/src/libopensc/apdu.c#L415
> https://github.com/OpenSC/OpenSC/blob/master/src/libopensc/apdu.c#L392
Yes this looks like a bug as SC_MAX_APDU_BUFFER_SIZE is for max size of ADPU
that can be sent, not size of receive buffer:
#define SC_MAX_APDU_BUFFER_SIZE 261 /* takes account of: CLA INS P1 P2
Lc [255 byte of data] Le */
>
> A quick fix would be to use 0xff+1/0xffff+1 instead. However, in
> multiple files I have seen this wrong usage of SC_MAX_APDU_BUFFER_SIZE
> (eg, see `grep rbuf *.c | grep SC_MAX_APDU_BUFFER_SIZE`). Unfortunately
> I dont have time to check libopensc in depth, so I leave this up to the
> community.
>
Do you mean something like this:
--- ,apdu.c Tue Dec 4 08:43:40 2012
+++ apdu.c Tue Dec 11 09:50:50 2012
@@ -389,7 +389,7 @@
if (apdu->resplen == 0 || apdu->resp == NULL)
goto error;
/* return buffer to small */
- if ((apdu->le == 0 && apdu->resplen < SC_MAX_APDU_BUFFER_SIZE-2)
+ if ((apdu->le == 0 && apdu->resplen < ((apdu->cse &
SC_APDU_EXT) ? 65536 : 256))
|| (apdu->resplen < apdu->le))
goto error;
break;
@@ -412,7 +412,7 @@
if (apdu->resplen == 0 || apdu->resp == NULL)
goto error;
/* return buffer to small */
- if ((apdu->le == 0 && apdu->resplen < SC_MAX_APDU_BUFFER_SIZE-2)
+ if ((apdu->le == 0 && apdu->resplen < ((apdu->cse & SC_APDU_EXT) ?
65536 : 256)
|| (apdu->resplen < apdu->le))
goto error;
/* inconsistent datalen */
>
>
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> opensc-devel@lists.opensc-project.org
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>
--
Douglas E. Engert <deeng...@anl.gov>
Argonne National Laboratory
9700 South Cass Avenue
Argonne, Illinois 60439
(630) 252-5444
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