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After freeing packet the code uses packet->next Its more of an issue when task_woken is NULL meaning we are not in ISR Also added fast bail out with return to jump out of while loop
After freeing packet the code uses packet->next Its more of an issue when task_woken is NULL meaning we are not in ISR Skip updating prev if packet is freed
The new return makes sure that it will not deref the freed packet next iter.
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Pull request overview
This PR fixes use-after-free behavior in the CAN and Ethernet pbuf linked-list management by ensuring traversal does not dereference freed nodes.
Changes:
- Add early
returnafter removing/freeing a specific pbuf in*_pbuf_free. - Update
*_pbuf_cleanupto cachenextbefore potential free and to avoid advancing via freed memory.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
src/interfaces/csp_if_eth_pbuf.c |
Prevents UAF by returning after free and by iterating cleanup via a cached next pointer. |
src/interfaces/csp_if_can_pbuf.c |
Same UAF prevention pattern applied to CAN pbuf free/cleanup traversal. |
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johandc
approved these changes
Mar 10, 2026
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This PR removes use after free from pbuf functions