From: Alexei Starovoitov <ast@kernel.org>
To: <davem@davemloft.net>
Cc: <daniel@iogearbox.net>, <dan.carpenter@oracle.com>,
<netdev@vger.kernel.org>, <bpf@vger.kernel.org>,
<kernel-team@fb.com>
Subject: [PATCH bpf-next] bpf: fix static checker warning
Date: Tue, 26 Nov 2019 15:01:06 -0800 [thread overview]
Message-ID: <20191126230106.237179-1-ast@kernel.org> (raw)
kernel/bpf/btf.c:4023 btf_distill_func_proto()
error: potentially dereferencing uninitialized 't'.
kernel/bpf/btf.c
4012 nargs = btf_type_vlen(func);
4013 if (nargs >= MAX_BPF_FUNC_ARGS) {
4014 bpf_log(log,
4015 "The function %s has %d arguments. Too many.\n",
4016 tname, nargs);
4017 return -EINVAL;
4018 }
4019 ret = __get_type_size(btf, func->type, &t);
^^
t isn't initialized for the first -EINVAL return
This is unlikely path, since BTF should have been validated at this point.
Fix it by returning 'void' BTF.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
kernel/bpf/btf.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 40efde5eedcb..bd5e11881ba3 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -3976,8 +3976,10 @@ static int __get_type_size(struct btf *btf, u32 btf_id,
t = btf_type_by_id(btf, btf_id);
while (t && btf_type_is_modifier(t))
t = btf_type_by_id(btf, t->type);
- if (!t)
+ if (!t) {
+ *bad_type = btf->types[0];
return -EINVAL;
+ }
if (btf_type_is_ptr(t))
/* kernel size of pointer. Not BPF's size of pointer*/
return sizeof(void *);
--
2.23.0
next reply other threads:[~2019-11-26 23:01 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-26 23:01 Alexei Starovoitov [this message]
2019-11-27 0:07 ` [PATCH bpf-next] bpf: fix static checker warning Daniel Borkmann
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