From 4f7a59b56a61018a3e76ef181190e94cdbb99565 Mon Sep 17 00:00:00 2001 From: Miaoqing Pan Date: Thu, 26 Sep 2019 16:16:50 +0800 Subject: [PATCH] nl80211: fix null pointer dereference [ Upstream commit b501426cf86e70649c983c52f4c823b3c40d72a3 ] If the interface is not in MESH mode, the command 'iw wlanx mpath del' will cause kernel panic. The root cause is null pointer access in mpp_flush_by_proxy(), as the pointer 'sdata->u.mesh.mpp_paths' is NULL for non MESH interface. Unable to handle kernel NULL pointer dereference at virtual address 00000068 [...] PC is at _raw_spin_lock_bh+0x20/0x5c LR is at mesh_path_del+0x1c/0x17c [mac80211] [...] Process iw (pid: 4537, stack limit = 0xd83e0238) [...] [] (_raw_spin_lock_bh) from [] (mesh_path_del+0x1c/0x17c [mac80211]) [] (mesh_path_del [mac80211]) from [] (extack_doit+0x20/0x68 [compat]) [] (extack_doit [compat]) from [] (genl_rcv_msg+0x274/0x30c) [] (genl_rcv_msg) from [] (netlink_rcv_skb+0x58/0xac) [] (netlink_rcv_skb) from [] (genl_rcv+0x20/0x34) [] (genl_rcv) from [] (netlink_unicast+0x11c/0x204) [] (netlink_unicast) from [] (netlink_sendmsg+0x30c/0x370) [] (netlink_sendmsg) from [] (sock_sendmsg+0x70/0x84) [] (sock_sendmsg) from [] (___sys_sendmsg.part.3+0x188/0x228) [] (___sys_sendmsg.part.3) from [] (__sys_sendmsg+0x4c/0x70) [] (__sys_sendmsg) from [] (ret_fast_syscall+0x0/0x44) Code: e2822c02 e2822001 e5832004 f590f000 (e1902f9f) ---[ end trace bbd717600f8f884d ]--- Signed-off-by: Miaoqing Pan Link: https://lore.kernel.org/r/1569485810-761-1-git-send-email-miaoqing@codeaurora.org [trim useless data from commit message] Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin --- net/wireless/nl80211.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index 95c8e682b491..2023802b6c77 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -4816,6 +4816,9 @@ static int nl80211_del_mpath(struct sk_buff *skb, struct genl_info *info) if (!rdev->ops->del_mpath) return -EOPNOTSUPP; + if (dev->ieee80211_ptr->iftype != NL80211_IFTYPE_MESH_POINT) + return -EOPNOTSUPP; + return rdev_del_mpath(rdev, dev, dst); }