From: Shung-Hsi Yu shung-hsi.yu@suse.com
[ Upstream commit d0d382f95a9270dcf803539d6781d6bd67e3f5b2 ]
When there are no program sections, obj->programs is left unallocated, and find_prog_by_sec_insn()'s search lands on &obj->programs[0] == NULL, and will cause null-pointer dereference in the following access to prog->sec_idx.
Guard the search with obj->nr_programs similar to what's being done in __bpf_program__iter() to prevent null-pointer access from happening.
Fixes: db2b8b06423c ("libbpf: Support CO-RE relocations for multi-prog sections") Signed-off-by: Shung-Hsi Yu shung-hsi.yu@suse.com Signed-off-by: Andrii Nakryiko andrii@kernel.org Link: https://lore.kernel.org/bpf/20221012022353.7350-4-shung-hsi.yu@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/lib/bpf/libbpf.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index a0d3cc39ea73..b9a29d105376 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -4115,6 +4115,9 @@ static struct bpf_program *find_prog_by_sec_insn(const struct bpf_object *obj, int l = 0, r = obj->nr_programs - 1, m; struct bpf_program *prog;
+ if (!obj->nr_programs) + return NULL; + while (l < r) { m = l + (r - l + 1) / 2; prog = &obj->programs[m];