From 647d446d66e493d23ca1047fa8492b0269674530 Mon Sep 17 00:00:00 2001 From: Sean Young Date: Wed, 23 Jun 2021 22:37:54 +0100 Subject: media, bpf: Do not copy more entries than user space requested 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 --- drivers/media/rc/bpf-lirc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/media') diff --git a/drivers/media/rc/bpf-lirc.c b/drivers/media/rc/bpf-lirc.c index 3fe3edd80876..afae0afe3f81 100644 --- a/drivers/media/rc/bpf-lirc.c +++ b/drivers/media/rc/bpf-lirc.c @@ -326,7 +326,8 @@ 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); -- cgit v1.2.3