From: Shung-Hsi Yu Date: Wed, 12 Oct 2022 02:23:53 +0000 (+0800) Subject: libbpf: Fix null-pointer dereference in find_prog_by_sec_insn() X-Git-Tag: archive/raspbian/0.3-2+rpi1+deb11u1^2~1 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=934a37426ef9f1706adae10083029fb65ac7a21e;p=libbpf.git libbpf: Fix null-pointer dereference in find_prog_by_sec_insn() 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 Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20221012022353.7350-4-shung-hsi.yu@suse.com Gbp-Pq: Name 0002-libbpf-Fix-null-pointer-dereference-in-find_prog_by_.patch --- diff --git a/src/libbpf.c b/src/libbpf.c index 6ae748f..f8794e5 100644 --- a/src/libbpf.c +++ b/src/libbpf.c @@ -3502,6 +3502,9 @@ 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];