From: Kumar Kartikeya Dwivedi <memxor@gmail.com>
To: bpf@vger.kernel.org
Cc: Dave Marchevsky <davemarchevsky@fb.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Yonghong Song <yonghong.song@linux.dev>,
David Vernet <void@manifault.com>
Subject: [PATCH bpf-next v2 11/14] bpf: Fix kfunc callback register type handling
Date: Wed, 9 Aug 2023 17:11:13 +0530 [thread overview]
Message-ID: <20230809114116.3216687-12-memxor@gmail.com> (raw)
In-Reply-To: <20230809114116.3216687-1-memxor@gmail.com>
The kfunc code to handle KF_ARG_PTR_TO_CALLBACK does not check the reg
type before using reg->subprogno. This can accidently permit invalid
pointers from being passed into callback helpers (e.g. silently from
different paths). Likewise, reg->subprogno from the per-register type
union may not be meaningful either. We need to reject any other type
except PTR_TO_FUNC.
Cc: Dave Marchevsky <davemarchevsky@fb.com>
Fixes: 5d92ddc3de1b ("bpf: Add callback validation to kfunc verifier logic")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
---
kernel/bpf/verifier.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 13db1fa4163c..1c9a7a6ef906 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -11334,6 +11334,10 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_
break;
}
case KF_ARG_PTR_TO_CALLBACK:
+ if (reg->type != PTR_TO_FUNC) {
+ verbose(env, "arg%d expected pointer to func\n", i);
+ return -EINVAL;
+ }
meta->subprogno = reg->subprogno;
break;
case KF_ARG_PTR_TO_REFCOUNTED_KPTR:
--
2.41.0
next prev parent reply other threads:[~2023-08-09 11:43 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-09 11:41 [PATCH bpf-next v2 00/14] Exceptions - 1/2 Kumar Kartikeya Dwivedi
2023-08-09 11:41 ` [PATCH bpf-next v2 01/14] arch/x86: Implement arch_bpf_stack_walk Kumar Kartikeya Dwivedi
2023-08-09 11:41 ` [PATCH bpf-next v2 02/14] bpf: Implement support for adding hidden subprogs Kumar Kartikeya Dwivedi
2023-08-09 11:41 ` [PATCH bpf-next v2 03/14] bpf: Implement BPF exceptions Kumar Kartikeya Dwivedi
2023-08-22 5:12 ` Alexei Starovoitov
2023-08-22 12:53 ` Kumar Kartikeya Dwivedi
2023-08-09 11:41 ` [PATCH bpf-next v2 04/14] bpf: Refactor check_btf_func and split into two phases Kumar Kartikeya Dwivedi
2023-08-09 11:41 ` [PATCH bpf-next v2 05/14] bpf: Add support for custom exception callbacks Kumar Kartikeya Dwivedi
2023-08-28 22:11 ` Martin KaFai Lau
2023-08-09 11:41 ` [PATCH bpf-next v2 06/14] bpf: Perform CFG walk for exception callback Kumar Kartikeya Dwivedi
2023-08-09 11:41 ` [PATCH bpf-next v2 07/14] bpf: Treat first argument as return value for bpf_throw Kumar Kartikeya Dwivedi
2023-08-09 11:41 ` [PATCH bpf-next v2 08/14] bpf: Prevent KASAN false positive with bpf_throw Kumar Kartikeya Dwivedi
2023-08-22 16:23 ` Alexei Starovoitov
2023-08-30 16:53 ` Andrey Konovalov
2023-08-09 11:41 ` [PATCH bpf-next v2 09/14] bpf: Detect IP == ksym.end as part of BPF program Kumar Kartikeya Dwivedi
2023-08-09 11:41 ` [PATCH bpf-next v2 10/14] bpf: Disallow extensions to exception callbacks Kumar Kartikeya Dwivedi
2023-08-22 5:09 ` Alexei Starovoitov
2023-08-22 12:53 ` Kumar Kartikeya Dwivedi
2023-08-09 11:41 ` Kumar Kartikeya Dwivedi [this message]
2023-08-10 21:12 ` [PATCH bpf-next v2 11/14] bpf: Fix kfunc callback register type handling David Marchevsky
2023-08-09 11:41 ` [PATCH bpf-next v2 12/14] libbpf: Add support for custom exception callbacks Kumar Kartikeya Dwivedi
2023-08-22 16:34 ` Alexei Starovoitov
2023-08-22 16:58 ` Kumar Kartikeya Dwivedi
2023-08-22 19:20 ` Alexei Starovoitov
2023-08-25 18:43 ` Andrii Nakryiko
2023-08-26 22:41 ` Kumar Kartikeya Dwivedi
2023-08-27 22:27 ` Alexei Starovoitov
2023-08-09 11:41 ` [PATCH bpf-next v2 13/14] selftests/bpf: Add BPF assertion macros Kumar Kartikeya Dwivedi
2023-08-09 11:41 ` [PATCH bpf-next v2 14/14] selftests/bpf: Add tests for BPF exceptions Kumar Kartikeya Dwivedi
2023-08-22 21:22 ` [PATCH bpf-next v2 00/14] Exceptions - 1/2 Kumar Kartikeya Dwivedi
2023-08-22 22:07 ` Jose E. Marchesi
2023-08-22 22:39 ` Yonghong Song
2023-08-22 22:53 ` Kumar Kartikeya Dwivedi
2023-08-22 23:06 ` Alexei Starovoitov
2023-08-25 18:55 ` Andrii Nakryiko
2023-08-26 22:42 ` Kumar Kartikeya Dwivedi
2023-08-22 22:54 ` Kumar Kartikeya Dwivedi
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