[OpenSIPS-Devel] [OpenSIPS/opensips] 78909c: [topology_hiding] fix vulnerability in TH decoding

[Bogdan Andrei IANCU]

  Branch: refs/heads/master
  Home:   https://github.com/OpenSIPS/opensips
  Commit: 78909c344fe4c25718233e6a00f6e2bd19373be3
      https://github.com/OpenSIPS/opensips/commit/78909c344fe4c25718233e6a00f6e2bd19373be3
  Author: Bogdan-Andrei Iancu <bogdan at opensips.org>
  Date:   2021-01-08 (Fri, 08 Jan 2021)

  Changed paths:
    M modules/topology_hiding/topo_hiding_logic.c

  Log Message:
  -----------
  [topology_hiding] fix vulnerability in TH decoding

Extra checks were added to prevent buffer overflow/underflow when decoding the TH information (in non-dialog module) extracted from the Contact hdr. This information may be subject to malicious changes from an external attacker.

Credits for reporting and for the fix go to @wdoekes.
The suggested fix was re-worked a bit, but the idea is the same.
Fixes #2338