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authorSean Young <sean@mess.org>2021-06-23 22:37:54 +0100
committerDaniel Borkmann <daniel@iogearbox.net>2021-06-24 15:16:40 +0200
commit647d446d66e493d23ca1047fa8492b0269674530 (patch)
treeab4d15274b4ed507313302b02dd7e2d29c0a9284 /drivers/media
parentced50fc49f3bde2892c3d7fad7b3b6bfbc6ef90e (diff)
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 <sean@mess.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20210623213754.632-1-sean@mess.org
Diffstat (limited to 'drivers/media')
-rw-r--r--drivers/media/rc/bpf-lirc.c3
1 files changed, 2 insertions, 1 deletions
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);