netdev - [PATCH] Check for NULL ptr of btf in codegen

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Message-ID: <20220523194917.igkgorco42537arb@jup>
Date:   Mon, 23 May 2022 15:49:17 -0400
From:   Michael Mullin <masmullin@...il.com>
To:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...nel.org>, netdev@...r.kernel.org,
        bpf@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] Check for NULL ptr of btf in codegen_asserts

bpf_object__btf() can return a NULL value.  If bpf_object__btf returns
null, do not progress through codegen_asserts(). This avoids a null ptr
dereference at the call btf__type_cnt() in the function find_type_for_map()

Signed-off-by: Michael Mullin <masmullin@...il.com>
---
 tools/bpf/bpftool/gen.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index 4c9477ff748d..f158dc1c2149 100644
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -474,6 +474,9 @@ static void codegen_asserts(struct bpf_object *obj, const char *obj_name)
 	const struct btf_type *sec;
 	char map_ident[256], var_ident[256];
 
+	if (!btf)
+		return;
+
 	codegen("\
 		\n\
 		__attribute__((unused)) static void			    \n\
-- 
2.36.1