diff mbox series

[v2,bpf-next,07/10] bpf: enforce precision of R0 on program/async callback return

Message ID 20231129003620.1049610-8-andrii@kernel.org (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series BPF verifier retval logic fixes | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for bpf-next
netdev/apply fail Patch does not apply to bpf-next
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Commit Message

Andrii Nakryiko Nov. 29, 2023, 12:36 a.m. UTC 
Given we enforce a valid range for program and async callback return
value, we must mark R0 as precise to avoid incorrect state pruning.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
 kernel/bpf/verifier.c | 4 ++++
 1 file changed, 4 insertions(+)
diff mbox series

Patch

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 576d4250ea59..484756c82baa 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 &&