libkmod and depmod: Release memory on error paths #228
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evelikov
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Nov 6, 2024
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Sorry, we've got cconflicts and this now needs a rebase. |
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Rebased. |
Codecov ReportAttention: Patch coverage is
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@stoeckmann can we drop the The last commit uses it although we can live with an 2 extra lines of code. |
evelikov
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Nov 12, 2024
evelikov
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Nov 12, 2024
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lucasdemarchi
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Nov 15, 2024
Add a macro to reduce amount of explicit while-loops for removal of nodes and release of their associated data in code base. Signed-off-by: Tobias Stoeckmann <[email protected]>
If a list node could not be added, release already allocated data which was supposed to end up in list. Signed-off-by: Tobias Stoeckmann <[email protected]>
Check malloc return value and clean up resources if allocation fails. Signed-off-by: Tobias Stoeckmann <[email protected]>
Do not override pointers to first list nodes if appending failed, otherwise it's impossible to release already existing nodes of these lists afterwards. Remove the now unused function kmod_list_remove_n_latest as well. Signed-off-by: Tobias Stoeckmann <[email protected]>
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Add a macro to reduce amount of explicit while-loops for removal of nodes and release of their associated data in code base. Signed-off-by: Tobias Stoeckmann <[email protected]> Link: #228 Signed-off-by: Lucas De Marchi <[email protected]>
lucasdemarchi
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If a list node could not be added, release already allocated data which was supposed to end up in list. Signed-off-by: Tobias Stoeckmann <[email protected]> Link: #228 Signed-off-by: Lucas De Marchi <[email protected]>
lucasdemarchi
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Check malloc return value and clean up resources if allocation fails. Signed-off-by: Tobias Stoeckmann <[email protected]> Link: #228 Signed-off-by: Lucas De Marchi <[email protected]>
lucasdemarchi
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Do not override pointers to first list nodes if appending failed, otherwise it's impossible to release already existing nodes of these lists afterwards. Remove the now unused function kmod_list_remove_n_latest as well. Signed-off-by: Tobias Stoeckmann <[email protected]> Link: #228 Signed-off-by: Lucas De Marchi <[email protected]>
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Applied, thanks |
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The libkmod library as well as depmod leaked memory on error paths related to kmod_lists:
kmod_list_appendfailure (out of memory), the soon to belist->datawas not freedTo make it a lot easier to review, I have added
kmod_list_releasewhich is a macro and abstracts the explicit while-loops from the code. I use it for case 2 to handle error cases more smoothly. This in turn made functionkmod_list_remove_n_latestobsolete, so I removed it.Proof of Concept (for case 2):
Either compile kmod with address sanitizer (for leak detection) or use valgrind for modprobe call later on
Create a modules config with an alias resolving to two modules (first one can be created in memory, second one is too long)
The option
-ais important to not trigger a FATAL log, which would abort the modprobe call without trying to release all resources. Since the leak occurs in library code, it should be fixed so allocated memory can be freed when requested.