From eabe518de533a4291996020977054a7a7b78c7d3 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Sat, 2 Dec 2023 09:57:02 -0800 Subject: [PATCH] bpf: enforce precision of R0 on program/async callback return Given we enforce a valid range for program and async callback return value, we must mark R0 as precise to avoid incorrect state pruning. Fixes: b5dc0163d8fd ("bpf: precise scalar_value tracking") Acked-by: Eduard Zingerman Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20231202175705.885270-9-andrii@kernel.org Signed-off-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index c54944af1bccb..2cd150d6d141e 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -15138,6 +15138,10 @@ static int check_return_code(struct bpf_verifier_env *env, int regno, const char return -EINVAL; } + err = mark_chain_precision(env, regno); + if (err) + return err; + if (!retval_range_within(range, reg)) { verbose_invalid_scalar(env, reg, range, exit_ctx, reg_name); if (!is_subprog &&