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Fix null pointer dereference in ngram_model_read#438

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dhdaines merged 2 commits intomainfrom
fix-ngram-null-check
Oct 23, 2025
Merged

Fix null pointer dereference in ngram_model_read#438
dhdaines merged 2 commits intomainfrom
fix-ngram-null-check

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@lenzo-ka
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@lenzo-ka lenzo-ka commented Oct 14, 2025

Description

Fixes a null pointer dereference when reading malformed or empty ARPA language model files.

The NGRAM_ARPA case in ngram_model_read did not check if the model was NULL before proceeding, unlike other file type cases. This caused a crash in ngram_model_apply_weights when processing invalid files.

Changes:

  • Added null check after ngram_model_trie_read_arpa call
  • Returns NULL immediately if model read fails, consistent with other cases

Verification steps

  • Compiled successfully with no errors
  • Prevents NULL pointer dereference crash reported in the issue
  • Matches existing error handling pattern used in NGRAM_BIN case

Fixes #432

@lenzo-ka
Fix stack-buffer overflow in WAV chunk ID logging
5619ada 
Replace unsafe %s format specifier with %c%c%c%c to prevent
reading past the 4-byte non-null-terminated id buffer.

Fixes #431
@lenzo-ka
Fix null pointer dereference in ngram_model_read
5bb7ade 
Add null check for NGRAM_ARPA case to prevent crash when
reading malformed or empty language model files.

Fixes #432
@lenzo-ka lenzo-ka requested a review from dhdaines October 23, 2025 18:21
dhdaines
dhdaines approved these changes Oct 23, 2025
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Argh! Yes another one of these error string formatting issues. The NULL pointer check is totally sensible as well.

@dhdaines dhdaines merged commit 71b75d4 into main Oct 23, 2025
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@dhdaines dhdaines deleted the fix-ngram-null-check branch October 23, 2025 20:27
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Missing null check in ngram_model_read for NGRAM_ARPA

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