linux-kernel - [PATCH AUTOSEL 6.6 01/21] wifi: cfg80211: fix missing interfaces when dumping

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date: Fri,  2 Feb 2024 13:39:48 -0500
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Michal Kazior <michal@...me.com>,
	Johannes Berg <johannes.berg@...el.com>,
	Sasha Levin <sashal@...nel.org>,
	johannes@...solutions.net,
	davem@...emloft.net,
	edumazet@...gle.com,
	kuba@...nel.org,
	pabeni@...hat.com,
	linux-wireless@...r.kernel.org,
	netdev@...r.kernel.org
Subject: [PATCH AUTOSEL 6.6 01/21] wifi: cfg80211: fix missing interfaces when dumping

From: Michal Kazior <michal@...me.com>

[ Upstream commit a6e4f85d3820d00694ed10f581f4c650445dbcda ]

The nl80211_dump_interface() supports resumption
in case nl80211_send_iface() doesn't have the
resources to complete its work.

The logic would store the progress as iteration
offsets for rdev and wdev loops.

However the logic did not properly handle
resumption for non-last rdev. Assuming a system
with 2 rdevs, with 2 wdevs each, this could
happen:

 dump(cb=[0, 0]):
  if_start=cb[1] (=0)
  send rdev0.wdev0 -> ok
  send rdev0.wdev1 -> yield
  cb[1] = 1

 dump(cb=[0, 1]):
  if_start=cb[1] (=1)
  send rdev0.wdev1 -> ok
  // since if_start=1 the rdev0.wdev0 got skipped
  // through if_idx < if_start
  send rdev1.wdev1 -> ok

The if_start needs to be reset back to 0 upon wdev
loop end.

The problem is actually hard to hit on a desktop,
and even on most routers. The prerequisites for
this manifesting was:
 - more than 1 wiphy
 - a few handful of interfaces
 - dump without rdev or wdev filter

I was seeing this with 4 wiphys 9 interfaces each.
It'd miss 6 interfaces from the last wiphy
reported to userspace.

Signed-off-by: Michal Kazior <michal@...me.com>
Link: https://msgid.link/20240116142340.89678-1-kazikcz@gmail.com
Signed-off-by: Johannes Berg <johannes.berg@...el.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 net/wireless/nl80211.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 0b0dfecedc50..c8bfacd5c8f3 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -4012,6 +4012,7 @@ static int nl80211_dump_interface(struct sk_buff *skb, struct netlink_callback *
 			if_idx++;
 		}
 
+		if_start = 0;
 		wp_idx++;
 	}
  out:
-- 
2.43.0