scd: Fix possible NULL deref in apdu.c
* scd/apdu.c (control_pcsc_direct): Take care of BUFLEN being NULL. (control_pcsc_wrapped): Ditto.
pcsc_vendor_specific_init calls the above with BUFFER and BUFLEN as
NULL.
Reported by Stack 0.3:
bug: anti-dce
model: |
control_pcsc.exit77:
%retval.0.i.i76 = phi i32 [ %rc.0.i.i.i73, \
%pcsc_error_to_sw.exit.i.i74 ], [ 0, %if.end.i.i75 ]
%tobool198 = icmp ne i32 %retval.0.i.i76, 0, !dbg !728
br i1 %tobool198, label %if.then199, label %if.end200, !dbg !728
stack:
- /home/wk/s/gnupg/scd/apdu.c:1882:0
ncore: 1
core:
- /home/wk/s/gnupg/scd/apdu.c:1309:0
- buffer overflow(backported from 2.1 commit ef0a3abf7305133d071bf1a94a7f461082f9a9aa)