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>,
Puranjay Mohan <puranjay12@gmail.com>
Subject: [PATCH bpf-next v3 13/17] bpf: Fix kfunc callback register type handling
Date: Wed, 13 Sep 2023 01:32:10 +0200 [thread overview]
Message-ID: <20230912233214.1518551-14-memxor@gmail.com> (raw)
In-Reply-To: <20230912233214.1518551-1-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.
Acked-by: 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 21e37e46d792..dff8c43dea0c 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -11407,6 +11407,10 @@ 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:[~2023-09-12 23:32 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-12 23:31 [PATCH bpf-next v3 00/17] Exceptions - 1/2 Kumar Kartikeya Dwivedi
2023-09-12 23:31 ` [PATCH bpf-next v3 01/17] bpf: Use bpf_is_subprog to check for subprogs Kumar Kartikeya Dwivedi
2023-09-12 23:31 ` [PATCH bpf-next v3 02/17] arch/x86: Implement arch_bpf_stack_walk Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 03/17] bpf: Implement support for adding hidden subprogs Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 04/17] bpf: Implement BPF exceptions Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 05/17] bpf: Refactor check_btf_func and split into two phases Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 06/17] bpf: Add support for custom exception callbacks Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 07/17] bpf: Perform CFG walk for exception callback Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 08/17] bpf: Treat first argument as return value for bpf_throw Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 09/17] mm: kasan: Declare kasan_unpoison_task_stack_below in kasan.h Kumar Kartikeya Dwivedi
2023-09-16 16:24 ` Andrey Konovalov
2023-09-12 23:32 ` [PATCH bpf-next v3 10/17] bpf: Prevent KASAN false positive with bpf_throw Kumar Kartikeya Dwivedi
2023-09-16 16:25 ` Andrey Konovalov
2023-09-18 13:20 ` Matthieu Baerts
2023-09-18 13:26 ` Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 11/17] bpf: Detect IP == ksym.end as part of BPF program Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 12/17] bpf: Disallow fentry/fexit/freplace for exception callbacks Kumar Kartikeya Dwivedi
2023-09-13 15:24 ` Puranjay Mohan
2023-09-14 12:13 ` Kumar Kartikeya Dwivedi
2023-09-16 16:44 ` Alexei Starovoitov
2023-09-16 17:30 ` Kumar Kartikeya Dwivedi
2023-09-16 19:34 ` Kumar Kartikeya Dwivedi
2023-09-18 1:56 ` Alexei Starovoitov
2023-09-12 23:32 ` Kumar Kartikeya Dwivedi [this message]
2023-09-12 23:32 ` [PATCH bpf-next v3 14/17] libbpf: Refactor bpf_object__reloc_code Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 15/17] libbpf: Add support for custom exception callbacks Kumar Kartikeya Dwivedi
2023-09-20 0:25 ` Andrii Nakryiko
2023-09-20 1:02 ` Kumar Kartikeya Dwivedi
2023-09-20 17:08 ` Andrii Nakryiko
2023-09-12 23:32 ` [PATCH bpf-next v3 16/17] selftests/bpf: Add BPF assertion macros Kumar Kartikeya Dwivedi
2023-09-12 23:32 ` [PATCH bpf-next v3 17/17] selftests/bpf: Add tests for BPF exceptions Kumar Kartikeya Dwivedi
2023-09-13 15:14 ` Puranjay Mohan
2023-09-13 16:12 ` Puranjay Mohan
2023-09-12 23:37 ` [PATCH bpf-next v3 00/17] Exceptions - 1/2 Kumar Kartikeya Dwivedi
2023-09-12 23:53 ` Puranjay Mohan
2023-09-16 16:50 ` patchwork-bot+netdevbpf
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