Fix potential use-after-free and double-free#4044
Merged
clumens merged 1 commit intoClusterLabs:mainfrom Feb 5, 2026
Merged
Conversation
|
Can one of the project admins check and authorise this run please: https://ci.kronosnet.org/job/pacemaker/job/pacemaker-pipeline/job/PR-4044/1/input |
clumens
requested changes
Feb 2, 2026
In pcmk__output_new() -> pcmk__bare_output_new(), when the condition if ((*out)->init(*out) == false) is met, pcmk__output_free(*out) is called and the function returns with rc = ENOMEM. The *_init() functions return false when memory allocation via calloc() fails - an unlikely but possible scenario. Since rc != pcmk_rc_ok, execution jumps to the done label after pcmk__output_new() returns. The codebase contains numerous functions that follow the same cleanup pattern: they check if (out != NULL) at the done label before invoking out->finish() and pcmk__output_free(out). Because *out is freed but not set to NULL on initialization failure, this check evaluates to true. This leads to: - Use-after-free: dereferencing the dangling pointer when calling out->finish(...); - Double-free: attempting to free the same memory again via pcmk__output_free(out). To resolve this, use g_clear_pointer(out, pcmk__output_free) within pcmk__bare_output_new(). This ensures that if (out != NULL) check at the done label is false, thereby preventing both the use-after-free and the double-free. Also update the copyright date. Signed-off-by: Alexandra Diupina <dyupina99999@gmail.com>
dyupina
force-pushed
the
main__fix_use_after_free_and_double_free
branch
from
bf8dc11 to
82ea8b9
Compare
|
Can one of the project admins check and authorise this run please: https://ci.kronosnet.org/job/pacemaker/job/pacemaker-pipeline/job/PR-4044/2/input |
clumens
approved these changes
Feb 5, 2026
Contributor
|
There's one more spot that could use |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
In pcmk__output_new() -> pcmk__bare_output_new(), when the condition if ((*out)->init(*out) == false) is met, pcmk__output_free(*out) is called and the function returns with rc = ENOMEM.
The *_init() functions return false when memory allocation via calloc() fails - an unlikely but possible scenario.
Since rc != pcmk_rc_ok, execution jumps to the done label after pcmk__output_new() returns.
The codebase contains numerous functions that follow the same cleanup pattern: they check if (out != NULL) at the done label before invoking out->finish() and pcmk__output_free(out). Because *out is freed but not set to NULL on initialization failure, this check evaluates to true.
This leads to:
To resolve this, set *out = NULL immediately after calling pcmk__output_free(*out) within pcmk__bare_output_new(). This ensures that if (out != NULL) check at the done label is false, thereby preventing both the use-after-free and the double-free.