[7.0] ldpd: add missing sanity check in the parsing of label messages

[rwestphal]

Validate that the FEC prefix length is within the allowed limit
(depending on the FEC address family) in order to prevent possible
buffer overflows in the ldpe child process.

Signed-off-by: Renato Westphal renato@opensourcerouting.org

[LabN-CI]

💚 Basic BGPD CI results: SUCCESS, 0 tests failed

Results table

_	_
Result	FAILURE git master f935dca frr.github Build
Date	10/23/2019
Start	20:20:14
Finish	20:21:02
Run-Time	00:48
Total
Pass
Fail
Valgrind-Errors
Valgrind-Loss
Details	vncregress-2019-10-23-20:20:14.txt
Log	make-2019-10-23-20:20:14.out.bz2
Memory
SUCCESS git merge/5338 80ecb9c	SUCCESS git merge/4975 4e5441e
11/13/2019	09/12/2019
20:20:11	20:20:16
20:45:55	20:42:04
25:44	21:48
1815	1815
1815	1815
0	0
0	0
0	0
vncregress-2019-11-13-20:20:11.txt	vncregress-2019-09-12-20:20:16.txt
autoscript-2019-11-13-20:20:58.log.bz2	autoscript-2019-09-12-20:21:04.log.bz2
442 437 366	425 421 360

For details, please contact louberger

[NetDEF-CI]

Continuous Integration Result: SUCCESSFUL

Congratulations, this patch passed basic tests

Tested-by: NetDEF / OpenSourceRouting.org CI System

CI System Testrun URL: https://ci1.netdef.org/browse/FRR-FRRPULLREQ-9699/

This is a comment from an automated CI system.
For questions and feedback in regards to this CI system, please feel free to email
Martin Winter - mwinter (at) opensourcerouting.org.

---

CLANG Static Analyzer Summary

• Github Pull Request 5338, comparing to Git base SHA 516f219

No Changes in Static Analysis warnings compared to base

67 Static Analyzer issues remaining.

See details at
https://ci1.netdef.org/browse/FRR-FRRPULLREQ-9699/artifact/shared/static_analysis/index.html