[PR #1794] fix(dvb_subtitle_decoder): add NULL checks after malloc calls #2531

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claunia · 2026-01-29T17:22:37Z

claunia commented

2026-01-29 17:22:37 +00:00

Original Pull Request: https://github.com/CCExtractor/ccextractor/pull/1794

State: closed
Merged: Yes

Summary

This PR adds missing NULL checks for 9 malloc() calls in the DVB subtitle decoder (src/lib_ccx/dvb_subtitle_decoder.c) that could cause crashes or undefined behavior if memory allocation fails.

Changes

All checks use fatal(EXIT_NOT_ENOUGH_MEMORY, ...) to terminate gracefully with an appropriate error message, consistent with the approach used in matroska.c and other parts of the codebase.

Affected Functions and Allocations

Function	Allocation	Line
`dvbsub_init_decoder()`	`DVBSubContext`	424
`dvbsub_parse_clut_segment()`	`DVBSubCLUT`	1146
`dvbsub_parse_region_segment()`	`DVBSubRegion`	1254
`dvbsub_parse_region_segment()`	`region->pbuf`	1287
`dvbsub_parse_region_segment()`	`DVBSubObject`	1332
`dvbsub_parse_region_segment()`	`DVBSubObjectDisplay`	1347
`dvbsub_parse_page_segment()`	`DVBSubRegionDisplay`	1438
`write_dvb_sub()`	`cc_bitmap` (rect)	1553
`write_dvb_sub()`	`rect->data1`	1636
`write_dvb_sub()`	`rect->data0`	1656
`dvbsub_handle_display_segment()`	`private_data`	1768

Additional Fix

This also fixes a potential memory leak in write_dvb_sub() where rect and rect->data1 would be leaked if the rect->data0 allocation failed (previously returned -1 without cleanup, now terminates via fatal()).

Context

This is part of a systematic effort to improve memory safety across the CCExtractor codebase. The DVB subtitle decoder was identified as having 28 memory-related function calls, making it a high-priority target for review.

Test plan

Code compiles without errors
Run with DVB subtitle streams to verify normal operation
Memory allocation failures will now produce clear error messages instead of crashes

🤖 Generated with Claude Code

**Original Pull Request:** https://github.com/CCExtractor/ccextractor/pull/1794 **State:** closed **Merged:** Yes --- ## Summary This PR adds missing NULL checks for **9 malloc() calls** in the DVB subtitle decoder (`src/lib_ccx/dvb_subtitle_decoder.c`) that could cause crashes or undefined behavior if memory allocation fails. ### Changes All checks use `fatal(EXIT_NOT_ENOUGH_MEMORY, ...)` to terminate gracefully with an appropriate error message, consistent with the approach used in `matroska.c` and other parts of the codebase. ### Affected Functions and Allocations | Function | Allocation | Line | |----------|------------|------| | `dvbsub_init_decoder()` | `DVBSubContext` | 424 | | `dvbsub_parse_clut_segment()` | `DVBSubCLUT` | 1146 | | `dvbsub_parse_region_segment()` | `DVBSubRegion` | 1254 | | `dvbsub_parse_region_segment()` | `region->pbuf` | 1287 | | `dvbsub_parse_region_segment()` | `DVBSubObject` | 1332 | | `dvbsub_parse_region_segment()` | `DVBSubObjectDisplay` | 1347 | | `dvbsub_parse_page_segment()` | `DVBSubRegionDisplay` | 1438 | | `write_dvb_sub()` | `cc_bitmap` (rect) | 1553 | | `write_dvb_sub()` | `rect->data1` | 1636 | | `write_dvb_sub()` | `rect->data0` | 1656 | | `dvbsub_handle_display_segment()` | `private_data` | 1768 | ### Additional Fix This also fixes a **potential memory leak** in `write_dvb_sub()` where `rect` and `rect->data1` would be leaked if the `rect->data0` allocation failed (previously returned -1 without cleanup, now terminates via `fatal()`). ### Context This is part of a systematic effort to improve memory safety across the CCExtractor codebase. The DVB subtitle decoder was identified as having 28 memory-related function calls, making it a high-priority target for review. ## Test plan - [x] Code compiles without errors - [ ] Run with DVB subtitle streams to verify normal operation - [ ] Memory allocation failures will now produce clear error messages instead of crashes 🤖 Generated with [Claude Code](https://claude.com/claude-code)

claunia added the pull-request label 2026-01-29 17:22:37 +00:00

claunia closed this issue

2026-01-29 17:22:37 +00:00

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Reference: starred/ccextractor#2531