Fix os_mbuf_dup() mixed-pool overflow & add robust selftests #3509
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Funciton os_mbuf_dup() can overflow on mixed-pool mbuf chains. It assumes all mbufs match the first pool’s size and memcpy()s larger segments past the destination. Make duplication pool-aware.
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Adds a test that duplicates a small and large mbuf chain. verifies the second segment comes from the correct pool. Checks lengths/payloads, and uses inner/outer guards to catch memcpy overruns—exposing “all-from-head” bug.
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kasjer
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Oct 15, 2025
sjanc
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Oct 15, 2025
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This PR fixes a bug in os_mbuf_dup() that could corrupt memory when duplicating an mbuf chain built from multiple pools of different payload sizes. The previous implementation assumed all segments could be duplicated from the head segment’s pool. When a later segment was larger than the head’s payload size, the memcpy() could write past the destination buffer.
The fix itself is based on apache/mynewt-nimble#2118