[PR #1805] fix(encoders): replace sprintf/strcpy with bounds-checked versions #2549

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claunia · 2026-01-29T17:22:43Z

claunia commented

2026-01-29 17:22:43 +00:00

Original Pull Request: https://github.com/CCExtractor/ccextractor/pull/1805

State: closed
Merged: Yes

Summary

This PR continues the Phase 3 buffer safety work from the bug analysis plan, replacing unsafe string functions with bounds-checked alternatives:

ccx_encoders_sami.c: 10 sprintf → snprintf conversions
ccx_encoders_srt.c: 6 sprintf → snprintf conversions
mp4.c: 6 fixes including:
- sprintf/strcpy/strcat → snprintf
- Critical fix: Buffer overflow in format_duration() where 20-byte buffer was too small for long duration strings (e.g., "365 Days, 23:59:59.999" = 22+ chars)
- Added size parameter to format_duration() function
ccx_encoders_webvtt.c: 6 sprintf → snprintf conversions, plus:
- Fixed malloc size bug (+4 instead of +5 for null terminator)
- Added OOM checks for css_file_name and outline_css_file
- Fixed memory leaks (allocated strings were not freed)

Test plan

Build completes successfully
Test with SAMI output format
Test with SRT output format
Test with WebVTT output format (including CSS generation)
Test with MP4 files containing chapters

🤖 Generated with Claude Code

**Original Pull Request:** https://github.com/CCExtractor/ccextractor/pull/1805 **State:** closed **Merged:** Yes --- ## Summary This PR continues the Phase 3 buffer safety work from the bug analysis plan, replacing unsafe string functions with bounds-checked alternatives: - **ccx_encoders_sami.c**: 10 `sprintf` → `snprintf` conversions - **ccx_encoders_srt.c**: 6 `sprintf` → `snprintf` conversions - **mp4.c**: 6 fixes including: - `sprintf`/`strcpy`/`strcat` → `snprintf` - **Critical fix**: Buffer overflow in `format_duration()` where 20-byte buffer was too small for long duration strings (e.g., "365 Days, 23:59:59.999" = 22+ chars) - Added size parameter to `format_duration()` function - **ccx_encoders_webvtt.c**: 6 `sprintf` → `snprintf` conversions, plus: - Fixed malloc size bug (`+4` instead of `+5` for null terminator) - Added OOM checks for `css_file_name` and `outline_css_file` - Fixed memory leaks (allocated strings were not freed) ## Test plan - [x] Build completes successfully - [ ] Test with SAMI output format - [ ] Test with SRT output format - [ ] Test with WebVTT output format (including CSS generation) - [ ] Test with MP4 files containing chapters 🤖 Generated with [Claude Code](https://claude.com/claude-code)

claunia added the pull-request label 2026-01-29 17:22:43 +00:00

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Reference: starred/ccextractor#2549