Re: application.c be more paranoid for misbehaving backends

[Sebastian Benoit]

Martijn van Duren(openbsd+t...@list.imperialat.at) on 2022.01.20 22:53:06 +0100:
> There's a missing NULL check in appl_response(). This should only happenwhen 
> a backend is misbehaving, so I only managed to find this because
> I'm actively bashing it right now. This should make us a little more
> future-proof. Code further down the path already has similar NULL checks
> against this variable.
> 
> OK?

ok

> 
> martijn@
> 
> Index: application.c
> ===
> RCS file: /cvs/src/usr.sbin/snmpd/application.c,v
> retrieving revision 1.1
> diff -u -p -r1.1 application.c
> --- application.c 19 Jan 2022 10:59:35 -  1.1
> +++ application.c 20 Jan 2022 21:52:41 -
> @@ -1056,7 +1056,8 @@ appl_response(struct appl_backend *backe
>   appl_varbind_error(origvb, error);
>   origvb->avi_state = APPL_VBSTATE_DONE;
>   origvb->avi_varbind.av_oid = vb->av_oid;
> - if (vb->av_value->be_class == BER_CLASS_CONTEXT &&
> + if (vb->av_value != NULL &&
> + vb->av_value->be_class == BER_CLASS_CONTEXT &&
>   vb->av_value->be_type == APPL_EXC_ENDOFMIBVIEW) {
>   nregion = appl_region_next(ureq->aru_ctx,
>   &(vb->av_oid), origvb->avi_region);
> 

application.c be more paranoid for misbehaving backends

[Martijn van Duren]

There's a missing NULL check in appl_response(). This should only happenwhen a 
backend is misbehaving, so I only managed to find this because
I'm actively bashing it right now. This should make us a little more
future-proof. Code further down the path already has similar NULL checks
against this variable.

OK?

martijn@

Index: application.c
===
RCS file: /cvs/src/usr.sbin/snmpd/application.c,v
retrieving revision 1.1
diff -u -p -r1.1 application.c
--- application.c   19 Jan 2022 10:59:35 -  1.1
+++ application.c   20 Jan 2022 21:52:41 -
@@ -1056,7 +1056,8 @@ appl_response(struct appl_backend *backe
appl_varbind_error(origvb, error);
origvb->avi_state = APPL_VBSTATE_DONE;
origvb->avi_varbind.av_oid = vb->av_oid;
-   if (vb->av_value->be_class == BER_CLASS_CONTEXT &&
+   if (vb->av_value != NULL &&
+   vb->av_value->be_class == BER_CLASS_CONTEXT &&
vb->av_value->be_type == APPL_EXC_ENDOFMIBVIEW) {
nregion = appl_region_next(ureq->aru_ctx,
&(vb->av_oid), origvb->avi_region);