sqlite: check null returns from sqlite value functions

[ndossche]

sqlite3_column_text() can return nullptr on failure which was not handled. sqlite3_column_blob() can return nullptr for zero-length BLOBs, which is then passed to memcpy() which is UB. Avoid this by checking for a nullptr.

Note: this was found by a static-dynamic analyser I'm developing.

[nodejs-github-bot]

Review requested:

• @nodejs/sqlite

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.29%. Comparing base (85d4755) to head (02db86a).
⚠️ Report is 9 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #63288      +/-   ##
==========================================
- Coverage   90.30%   90.29%   -0.01%     
==========================================
  Files         759      759              
  Lines      247754   247754              
  Branches    46716    46720       +4     
==========================================
- Hits       223724   223719       -5     
- Misses      15483    15512      +29     
+ Partials     8547     8523      -24     

Files with missing lines	Coverage Δ
src/node_sqlite.cc	80.84% <ø> (ø)

... and 38 files with indirect coverage changes

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[trivikr]

@ndossche Can you please rebase and force push?

[ndossche]

Done, CI (so far) is looking okay

[trivikr]

Can you add some regression tests? Ones which fail in main, but succeed with the fix?

[ndossche]

Can you add some regression tests? Ones which fail in main, but succeed with the fix?

Apparently the current test suite can already trigger the "UB blob" problem, but the test runner ignores UBSAN failures, so you never see this as a failure.
Compile node.js with ubsan, and then set the environment variable export UBSAN_OPTIONS='print_stacktrace=1:halt_on_error=1' and then run: ./tools/test.py test/parallel/test-sqlite-data-types.js
This will show the failed test and crash backtrace.

As for the allocation failure in SQLITE_TEXT, I don't think I can make a reliable reproducer.

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/75594/