From b501426cf86e70649c983c52f4c823b3c40d72a3 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 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 --- net/wireless/nl80211.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index 10617566a117..141cdb171665 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -6305,6 +6305,9 @@ 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); }