bpf: enforce precision of R0 on callback return

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Given verifier checks actual value, r0 has to be precise, so we need to
propagate precision properly. r0 also has to be marked as read,
otherwise subsequent state comparisons will ignore such register as
unimportant and precision won't really help here.

Fixes: 69c087ba62 ("bpf: Add bpf_for_each_map_elem() helper")
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231202175705.885270-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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Andrii Nakryiko 2023-12-02 09:56:57 -08:00 • committed by Alexei Starovoitov

parent 5fad52bee3

commit 0acd03a5bd

1 changed files with 7 additions and 0 deletions

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kernel/bpf/verifier.c

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