From: Andrii Nakryiko <andrii@kernel.org>
To: <bpf@vger.kernel.org>, <ast@kernel.org>, <daniel@iogearbox.net>,
<martin.lau@kernel.org>
Cc: <andrii@kernel.org>, <kernel-team@meta.com>,
Eduard Zingerman <eddyz87@gmail.com>
Subject: [PATCH v4 bpf-next 08/11] bpf: enforce precision of R0 on program/async callback return
Date: Fri, 1 Dec 2023 10:33:56 -0800 [thread overview]
Message-ID: <20231201183359.1769668-9-andrii@kernel.org> (raw)
In-Reply-To: <20231201183359.1769668-1-andrii@kernel.org>
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 <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
kernel/bpf/verifier.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index c54944af1bcc..2cd150d6d141 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 &&
--
2.34.1
next prev parent reply other threads:[~2023-12-01 18:34 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-01 18:33 [PATCH v4 bpf-next 00/11] BPF verifier retval logic fixes Andrii Nakryiko
2023-12-01 18:33 ` [PATCH v4 bpf-next 01/11] bpf: rearrange bpf_func_state fields to save a bit of memory Andrii Nakryiko
2023-12-01 18:33 ` [PATCH v4 bpf-next 02/11] bpf: provide correct register name for exception callback retval check Andrii Nakryiko
2023-12-01 18:33 ` [PATCH v4 bpf-next 03/11] bpf: enforce precision of R0 on callback return Andrii Nakryiko
2023-12-01 18:33 ` [PATCH v4 bpf-next 04/11] bpf: enforce exact retval range on subprog/callback exit Andrii Nakryiko
2023-12-01 18:33 ` [PATCH v4 bpf-next 05/11] selftests/bpf: add selftest validating callback result is enforced Andrii Nakryiko
2023-12-01 18:33 ` [PATCH v4 bpf-next 06/11] bpf: enforce precise retval range on program exit Andrii Nakryiko
2023-12-01 18:33 ` [PATCH v4 bpf-next 07/11] bpf: unify async callback and program retval checks Andrii Nakryiko
2023-12-01 18:33 ` Andrii Nakryiko [this message]
2023-12-01 18:33 ` [PATCH v4 bpf-next 09/11] selftests/bpf: validate async callback return value check correctness Andrii Nakryiko
2023-12-01 18:33 ` [PATCH v4 bpf-next 10/11] selftests/bpf: adjust global_func15 test to validate prog exit precision Andrii Nakryiko
2023-12-01 18:33 ` [PATCH v4 bpf-next 11/11] bpf: simplify tnum output if a fully known constant Andrii Nakryiko
2023-12-01 20:11 ` [PATCH v4 bpf-next 00/11] BPF verifier retval logic fixes Andrii Nakryiko
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