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memcpy() with overlapping src and dest buffers is an undefined behavior in C. In the current code, a ConfRej response is generated by copying input data in-place, where the dest address is lower than the src. This happens to work in practice because memcpy() forward-copies data, matching the behavior of memmove() in this case. However, if FORTIFY_SOURCE or Address Sanitizer is enabled, memcpy() will detect the overlap at run time and abort the program. Replace the memcpy() with memmove() to ensure a well-defined behavior. Reported-by: Filippo Carletti <filippo.carletti@gmail.com> Closes: #576 Signed-off-by: Qingfang Deng <dqfext@gmail.com>
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Seems reasonable, given that BSD bcopy() semantics allow overlapping source and destination. |
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@LGA1150: Thanks for your PR and @paulusmack for merging! |
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memcpy() with overlapping src and dest buffers is an undefined behavior in C. In the current code, a ConfRej response is generated by copying input data in-place, where the dest address is lower than the src. This happens to work in practice because memcpy() forward-copies data, matching the behavior of memmove() in this case.
However, if FORTIFY_SOURCE or Address Sanitizer is enabled, memcpy() will detect the overlap at run time and abort the program.
Replace the memcpy() with memmove() to ensure a well-defined behavior.
Closes: #576