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authorAndrii Nakryiko <andriin@fb.com>2019-07-19 12:32:42 -0700
committerAlexei Starovoitov <ast@kernel.org>2019-07-19 12:37:18 -0700
commit04efe5911fb30664a56ec63d272a0f39a71545db (patch)
treecc7cd8cf784c8f3e620c793aa7068a8fe43b2414 /tools/lib
parent8d650cdedaabb33e85e9b7c517c0c71fcecc1de9 (diff)
libbpf: fix SIGSEGV when BTF loading fails, but .BTF.ext exists
In case when BTF loading fails despite sanitization, but BPF object has .BTF.ext loaded as well, we free and null obj->btf, but not obj->btf_ext. This leads to an attempt to relocate .BTF.ext later on during bpf_object__load(), which assumes obj->btf is present. This leads to SIGSEGV on null pointer access. Fix bug by freeing and nulling obj->btf_ext as well. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools/lib')
-rw-r--r--tools/lib/bpf/libbpf.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 794dd5064ae8..87168f21ef43 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1500,6 +1500,12 @@ static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj)
BTF_ELF_SEC, err);
btf__free(obj->btf);
obj->btf = NULL;
+ /* btf_ext can't exist without btf, so free it as well */
+ if (obj->btf_ext) {
+ btf_ext__free(obj->btf_ext);
+ obj->btf_ext = NULL;
+ }
+
if (bpf_object__is_btf_mandatory(obj))
return err;
}