Fix late initialization of custom memory allocators in ndpiReader#3164
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ndpiReader was setting custom memory allocation hooks only inside test_lib(), which is executed after several code paths that already use nDPI APIs (e.g., parseOptions, help/extcap paths, host checks, DoH initialization, etc.). This could lead to inconsistent allocator usage where memory is allocated using the default libc allocator (when hooks are unset) and later freed using custom allocators, resulting in undefined behavior with non-trivial allocators. This change introduces ndpiReader_install_memory_hooks() and calls it early in main(), immediately after the API version check and before any nDPI-related operations. The duplicate hook initialization in test_lib() has been removed to ensure a single initialization point. Additionally, example/README.md has been updated to document the correct usage pattern for custom allocators. This partially addresses ntop#1280.
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IvanNardi
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Apr 20, 2026
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Thanks for the fix, the issue is real.
I slightly simplified your patch.
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@fabiodepin, thank you |
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ndpiReader was installing custom memory allocator hooks too late
(inside
test_lib()), after several execution paths had alreadyinvoked nDPI APIs that may allocate memory.
This could result in mixed allocator usage:
This is undefined behavior when using non-trivial allocators
(e.g., jemalloc, tcmalloc, custom pools).
Please sign (check) the below before submitting the Pull Request:
Link to the related 1280:
Changes:
ndpiReader_install_memory_hooks()main(), immediately after API version checktest_lib()example/README.mdto document correct allocator usageRationale
Ensuring that memory hooks are installed before any nDPI API usage
prevents inconsistent allocation/free pairs and avoids potential
memory corruption issues.
This change is limited to the example application (
ndpiReader)and does not modify libnDPI behavior or public APIs.
Relation to existing discussions
This partially addresses concerns raised in #1280 regarding
custom allocator usage and consistency.
Notes