fix(network): check buffer length before reading family in unpack_ip_port

[NoxToxCipher]

In unpack_ip_port, data[0] was accessed without verifying that length > 0, causing a potential 1-byte out-of-bounds read on 0-length input. Additionally, checked ip_port and data before dereferencing.

In unpack_nodes, add an entry check verifying nodes is non-null when max_num_nodes > 0.

Added boundary unit tests in auto_tests/network_test.c covering zero-length inputs, truncated IPv4/IPv6 buffers, and invalid address families.

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This change is 

[Green-Sky]

Thanks for the pr. We require commits to be signed by the author.

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./auto_tests/network_test.c:168:43: error: null passed to a callee that requires a non-null argument [-Werror,-Wnonnull]
  168 |     ck_assert_int_eq(unpack_ip_port(&ipp, nullptr, 10, false), -1);
      |                                           ^~~~~~~
./auto_tests/network_test.c:175:37: error: null passed to a callee that requires a non-null argument [-Werror,-Wnonnull]
  175 |     ck_assert_int_eq(unpack_ip_port(nullptr, dummy_v4, sizeof(dummy_v4), false), -1);
      |                                     ^~~~~~~

I think it would be best to remove those test cases, we have static annotation for a reason.

[NoxToxCipher]

Alright, on it. What do you think otherwise?

[Green-Sky]

Looks good, the other change is fine but not changing anything.

[Green-Sky]

Also please add your signing public key to github, so it knows it is you :)

[codecov]

Codecov Report

❌ Patch coverage is 66.66667% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 69.79%. Comparing base (efb938b) to head (03995e7).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
toxcore/DHT.c	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3073      +/-   ##
==========================================
- Coverage   69.82%   69.79%   -0.04%     
==========================================
  Files         185      185              
  Lines       34422    34424       +2     
==========================================
- Hits        24035    24025      -10     
- Misses      10387    10399      +12     

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[Green-Sky]

Update op and commit message (usually they are supposed to be a match).

Then it should be ready.

[Green-Sky]

good stuff