Fixes an assertion failure "pd->type == SD_DHCP6_OPTION_IA_PD" in dhcp6_option_append_pd().
Something similar was done in commit 26a63b8132 ('sd-dhcp6-client: Fix
sending prefix delegation request (#17136)'). The justification is
probably the same.
It's a follow-up to https://github.com/systemd/systemd/pull/10200 where
that fuzzer was introduced. At the time it was run regularly on machines
where machine-id wasn't present so it was kind of reproducible. Now
it's run on CIFuzz and CFLite using GHActions with the public OSS-Fuzz
corpora (based on that particular machine-id) so to fully utilize
those corpora it's necessary to use it always. Other than that
it makes it possible for fuzzers targeting outgoing packets
based on incoming packets like https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1795921
to get past client_parse_message on my machine :-)
When classless static routes option is provided, then static routes
option should not be used. Hence, let's not mix and store them in one
storage.
This introduce sd_dhcp_lease_get_static_routes() and
sd_dhcp_lease_get_classless_routes().
The destination address was read twice, one is for prefixlen, and
other is for destination address itself. And for prefixlen, the address
might be read from unaligned buffer.
This also modernizes the code.
Otherwise, if the second push is failed, then the first hashmap contains
dirty entry.
Also, this makes hashmap_remove_value() used when removing leases to
make not wrong lease is removed from the hashmap.
Note, this just hide the root cause of the issue #22253, which will be
fixed in later commit.
Fixes#22253.
Turns out that part of systemd isn't covered by any fuzz targets and
that's not ideal considering that it parses data sent remotely. The
fuzzer triggers an infinite loop in lease_parse_routes as soon as it
starts so it seems to be working :-)
```
INFO: Running with entropic power schedule (0xFF, 100).
INFO: Seed: 23620602
INFO: Loaded 2 modules (182073 inline 8-bit counters): 176548 [0x7fdf511fc8d0, 0x7fdf51227a74), 5525 [0x5f6ef0, 0x5f8485),
INFO: Loaded 2 PC tables (182073 PCs): 176548 [0x7fdf51227a78,0x7fdf514d94b8), 5525 [0x5f8488,0x60ddd8),
./build/fuzz-dhcp-client: Running 1 inputs 1 time(s) each.
Running: test/fuzz/fuzz-dhcp-client/timeout-ed34161922c7075c4773f2ada3dee8685d220980
ALARM: working on the last Unit for 31 seconds
and the timeout value is 30 (use -timeout=N to change)
==80731== ERROR: libFuzzer: timeout after 31 seconds
#0 0x51b32e in __sanitizer_print_stack_trace (/home/vagrant/systemd/build/fuzz-dhcp-client+0x51b32e)
#1 0x4689e9 in fuzzer::PrintStackTrace() (/home/vagrant/systemd/build/fuzz-dhcp-client+0x4689e9)
#2 0x44a0f4 in fuzzer::Fuzzer::StaticAlarmCallback() (/home/vagrant/systemd/build/fuzz-dhcp-client+0x44a0f4)
#3 0x7fdf4f8b474f (/lib64/libc.so.6+0x4274f)
#4 0x465fee in __sanitizer_cov_trace_const_cmp4 (/home/vagrant/systemd/build/fuzz-dhcp-client+0x465fee)
#5 0x57eee5 in lease_parse_routes /home/vagrant/systemd/build/../src/libsystemd-network/sd-dhcp-lease.c:495:23
#6 0x57baf3 in dhcp_lease_parse_options /home/vagrant/systemd/build/../src/libsystemd-network/sd-dhcp-lease.c:701:21
#7 0x572450 in parse_options /home/vagrant/systemd/build/../src/libsystemd-network/dhcp-option.c:348:33
#8 0x571cea in dhcp_option_parse /home/vagrant/systemd/build/../src/libsystemd-network/dhcp-option.c:381:21
#9 0x559a01 in client_handle_offer /home/vagrant/systemd/build/../src/libsystemd-network/sd-dhcp-client.c:1543:13
#10 0x5592bd in LLVMFuzzerTestOneInput /home/vagrant/systemd/build/../src/libsystemd-network/fuzz-dhcp-client.c:78:9
#11 0x44a379 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) (/home/vagrant/systemd/build/fuzz-dhcp-client+0x44a379)
#12 0x42ae1f in fuzzer::RunOneTest(fuzzer::Fuzzer*, char const*, unsigned long) (/home/vagrant/systemd/build/fuzz-dhcp-client+0x42ae1f)
#13 0x432ade in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) (/home/vagrant/systemd/build/fuzz-dhcp-client+0x432ade)
#14 0x421f86 in main (/home/vagrant/systemd/build/fuzz-dhcp-client+0x421f86)
#15 0x7fdf4f89f55f in __libc_start_call_main (/lib64/libc.so.6+0x2d55f)
#16 0x7fdf4f89f60b in __libc_start_main@GLIBC_2.2.5 (/lib64/libc.so.6+0x2d60b)
#17 0x421fd4 in _start (/home/vagrant/systemd/build/fuzz-dhcp-client+0x421fd4)
SUMMARY: libFuzzer: timeout
```
Yu Watanabe
Evgeny Vereshchagin
Thomas Haller