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Andrii Nakryiko authored
strncpy() has a notoriously error-prone semantics which makes GCC complain about it a lot (and quite often completely completely falsely at that). Instead of pleasing GCC all the time (-Wno-stringop-truncation is unfortunately only supported by GCC, so it's a bit too messy to just enable it in Makefile), add libbpf-internal libbpf_strlcpy() helper which follows what FreeBSD's strlcpy() does and what most people would expect from strncpy(): copies up to N-1 first bytes from source string into destination string and ensures zero-termination afterwards. Replace all the relevant uses of strncpy/strncat/memcpy in libbpf with libbpf_strlcpy(). This also fixes the issue reported by Emmanuel Deloget in xsk.c where memcpy() could access source string beyond its end. Fixes: 2f6324a3 (libbpf: Support shared umems between queues and devices) Reported-by:
Emmanuel Deloget <emmanuel.deloget@eho.link> Signed-off-by:
Andrii Nakryiko <andrii@kernel.org> Signed-off-by:
Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211211004043.2374068-1-andrii@kernel.org
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