It may happen that destination buffer memory overlaps with memory dynptr points to. Hence, we must use memmove to correctly copy from dynptr to destination buffer, or source buffer to dynptr. This actually isn't a problem right now, as memcpy implementation falls back to memmove on detecting overlap and warns about it, but we shouldn't be relying on that. Acked-by: Joanne Koong <joannelkoong@xxxxxxxxx> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx> --- kernel/bpf/helpers.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 714f5c9d0c1f..1099ed1e7712 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1489,7 +1489,7 @@ BPF_CALL_5(bpf_dynptr_read, void *, dst, u32, len, const struct bpf_dynptr_kern if (err) return err; - memcpy(dst, src->data + src->offset + offset, len); + memmove(dst, src->data + src->offset + offset, len); return 0; } @@ -1517,7 +1517,7 @@ BPF_CALL_5(bpf_dynptr_write, const struct bpf_dynptr_kern *, dst, u32, offset, v if (err) return err; - memcpy(dst->data + dst->offset + offset, src, len); + memmove(dst->data + dst->offset + offset, src, len); return 0; } -- 2.38.1
