From: Sean Young sean@mess.org
[ 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 sean@mess.org Signed-off-by: Daniel Borkmann daniel@iogearbox.net Link: https://lore.kernel.org/bpf/20210623213754.632-1-sean@mess.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 8b97fd1f0cea..5a0e26e47f59 100644 --- a/drivers/media/rc/bpf-lirc.c +++ b/drivers/media/rc/bpf-lirc.c @@ -295,7 +295,8 @@ 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);