From 3fbae80e24d65866e86edbb33a46efdd40501897 Mon Sep 17 00:00:00 2001 From: Sean Young Date: Wed, 23 Jun 2021 22:37:54 +0100 Subject: [PATCH] media, bpf: Do not copy more entries than user space requested [ Upstream commit 647d446d66e493d23ca1047fa8492b0269674530 ] The syscall bpf(BPF_PROG_QUERY, &attr) should use the prog_cnt field to see how many entries user space provided and return ENOSPC if there are more programs than that. Before this patch, this is not checked and ENOSPC is never returned. Note that one lirc device is limited to 64 bpf programs, and user space I'm aware of -- ir-keytable -- always gives enough space for 64 entries already. However, we should not copy program ids than are requested. Signed-off-by: Sean Young Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20210623213754.632-1-sean@mess.org Signed-off-by: Sasha Levin --- drivers/media/rc/bpf-lirc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/media/rc/bpf-lirc.c b/drivers/media/rc/bpf-lirc.c index 0a0ce620e4a29..d5f839fdcde7d 100644 --- a/drivers/media/rc/bpf-lirc.c +++ b/drivers/media/rc/bpf-lirc.c @@ -329,7 +329,8 @@ int lirc_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr) } if (attr->query.prog_cnt != 0 && prog_ids && cnt) - ret = bpf_prog_array_copy_to_user(progs, prog_ids, cnt); + ret = bpf_prog_array_copy_to_user(progs, prog_ids, + attr->query.prog_cnt); unlock: mutex_unlock(&ir_raw_handler_lock); -- 2.47.3