From: Ilya Leoshkevich <iii@linux.ibm.com>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>
Cc: bpf@vger.kernel.org, Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Alexander Gordeev <agordeev@linux.ibm.com>,
Jiri Olsa <jolsa@kernel.org>, Stanislav Fomichev <sdf@google.com>,
Ilya Leoshkevich <iii@linux.ibm.com>
Subject: [PATCH bpf-next] bpf: Check for helper calls in check_subprogs()
Date: Mon, 20 Feb 2023 17:37:56 +0100 [thread overview]
Message-ID: <20230220163756.753713-1-iii@linux.ibm.com> (raw)
The condition src_reg != BPF_PSEUDO_CALL && imm == BPF_FUNC_tail_call
may be satisfied by a kfunc call. This would lead to unnecessarily
setting has_tail_call. Use src_reg == 0 instead.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
kernel/bpf/verifier.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index e63af41a7e95..6d4632476c9c 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2462,8 +2462,8 @@ static int check_subprogs(struct bpf_verifier_env *env)
u8 code = insn[i].code;
if (code == (BPF_JMP | BPF_CALL) &&
- insn[i].imm == BPF_FUNC_tail_call &&
- insn[i].src_reg != BPF_PSEUDO_CALL)
+ insn[i].src_reg == 0 &&
+ insn[i].imm == BPF_FUNC_tail_call)
subprog[cur_subprog].has_tail_call = true;
if (BPF_CLASS(code) == BPF_LD &&
(BPF_MODE(code) == BPF_ABS || BPF_MODE(code) == BPF_IND))
--
2.39.1
next reply other threads:[~2023-02-20 16:38 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-20 16:37 Ilya Leoshkevich [this message]
2023-02-21 17:10 ` [PATCH bpf-next] bpf: Check for helper calls in check_subprogs() Stanislav Fomichev
2023-02-22 21:20 ` patchwork-bot+netdevbpf
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