bgpd: Check if we have really enough data before doing memcpy for software version (backport #16211) #16278
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…tware version
If we receive CAPABILITY message (software-version), we SHOULD check if we really
have enough data before doing memcpy(), that could also lead to buffer overflow.
(data + len > end) is not enough, because after this check we do data++ and later
memcpy(..., data, len). That means we have one more byte.
Hit this through fuzzing by
```
0 0xaaaaaadf872c in __asan_memcpy (/home/ubuntu/frr-public/frr_public_private-libfuzzer/bgpd/.libs/bgpd+0x35872c) (BuildId: 9c6e455d0d9a20f5a4d2f035b443f50add9564d7)
1 0xaaaaab06bfbc in bgp_dynamic_capability_software_version /home/ubuntu/frr-public/frr_public_private-libfuzzer/bgpd/bgp_packet.c:3713:3
2 0xaaaaab05ccb4 in bgp_capability_msg_parse /home/ubuntu/frr-public/frr_public_private-libfuzzer/bgpd/bgp_packet.c:3839:4
3 0xaaaaab05c074 in bgp_capability_receive /home/ubuntu/frr-public/frr_public_private-libfuzzer/bgpd/bgp_packet.c:3980:9
4 0xaaaaab05e48c in bgp_process_packet /home/ubuntu/frr-public/frr_public_private-libfuzzer/bgpd/bgp_packet.c:4109:11
5 0xaaaaaae36150 in LLVMFuzzerTestOneInput /home/ubuntu/frr-public/frr_public_private-libfuzzer/bgpd/bgp_main.c:582:3
```
Hit this again by Iggy \m/
Reported-by: Iggy Frankovic <iggyfran@amazon.com>
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
(cherry picked from commit 5d7af51)
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This is an automatic backport of pull request #16211 done by [Mergify](https://mergify.com).