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From: Siddh Raman Pant <code@siddh.me>
To: "Jakub Kicinski" <kuba@kernel.org>
Cc: "greg kh" <gregkh@linuxfoundation.org>,
	"johannes berg" <johannes@sipsolutions.net>,
	"david s. miller" <davem@davemloft.net>,
	"eric dumazet" <edumazet@google.com>,
	"paolo abeni" <pabeni@redhat.com>,
	"netdev" <netdev@vger.kernel.org>,
	"syzbot+6cb476b7c69916a0caca" 
	<syzbot+6cb476b7c69916a0caca@syzkaller.appspotmail.com>,
	"linux-wireless" <linux-wireless@vger.kernel.org>,
	"linux-kernel" <linux-kernel@vger.kernel.org>,
	"syzbot+f9acff9bf08a845f225d" 
	<syzbot+f9acff9bf08a845f225d@syzkaller.appspotmail.com>,
	"syzbot+9250865a55539d384347" 
	<syzbot+9250865a55539d384347@syzkaller.appspotmail.com>,
	"linux-kernel-mentees" 
	<linux-kernel-mentees@lists.linuxfoundation.org>
Subject: Re: [PATCH v2] wifi: cfg80211: Fix UAF in ieee80211_scan_rx()
Date: Sat, 13 Aug 2022 21:49:52 +0530	[thread overview]
Message-ID: <182980137c6.5665bf61226802.3084448395277966678@siddh.me> (raw)
In-Reply-To: <20220812122509.281f0536@kernel.org>

On Sat, 13 Aug 2022 00:55:09 +0530  Jakub Kicinski  wrote:
> Similarly to Greg, I'm not very familiar with the code base but one
> sure way to move things forward would be to point out a commit which
> broke things and put it in a Fixes tag. Much easier to validate a fix
> by looking at where things went wrong.

Thanks, I now looked at some history.

The following commit on 28 Sep 2020 put the kfree call before NULLing:
c8cb5b854b40 ("nl80211/cfg80211: support 6 GHz scanning")

The following commit on 19 Nov 2014 introduces RCU:
6ea0a69ca21b ("mac80211: rcu-ify scan and scheduled scan request pointers")

The kfree call wasn't "rcu-ified" in this commit, and neither were
RCU heads added.

The following commit on 18 Dec 2014 added RCU head for sched_scan_req:
31a60ed1e95a ("nl80211: Convert sched_scan_req pointer to RCU pointer")

It seems a similar thing might not have been done for scan_req, but I
could have also missed commits.

So what should go into the fixes tag, if any? Probably 6ea0a69ca21b?

Also, I probably should use RCU_INIT_POINTER in this patch. Or should
I make a patch somewhat like 31a60ed1e95a?

Thanks,
Siddh

WARNING: multiple messages have this Message-ID (diff)
From: Siddh Raman Pant via Linux-kernel-mentees <linux-kernel-mentees@lists.linuxfoundation.org>
To: "Jakub Kicinski" <kuba@kernel.org>
Cc: syzbot+9250865a55539d384347
	<syzbot+9250865a55539d384347@syzkaller.appspotmail.com>,
	syzbot+6cb476b7c69916a0caca
	<syzbot+6cb476b7c69916a0caca@syzkaller.appspotmail.com>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	syzbot+f9acff9bf08a845f225d
	<syzbot+f9acff9bf08a845f225d@syzkaller.appspotmail.com>,
	eric dumazet <edumazet@google.com>,
	netdev <netdev@vger.kernel.org>,
	johannes berg <johannes@sipsolutions.net>,
	paolo abeni <pabeni@redhat.com>,
	linux-kernel-mentees
	<linux-kernel-mentees@lists.linuxfoundation.org>,
	"david s. miller" <davem@davemloft.net>
Subject: Re: [PATCH v2] wifi: cfg80211: Fix UAF in ieee80211_scan_rx()
Date: Sat, 13 Aug 2022 21:49:52 +0530	[thread overview]
Message-ID: <182980137c6.5665bf61226802.3084448395277966678@siddh.me> (raw)
In-Reply-To: <20220812122509.281f0536@kernel.org>

On Sat, 13 Aug 2022 00:55:09 +0530  Jakub Kicinski  wrote:
> Similarly to Greg, I'm not very familiar with the code base but one
> sure way to move things forward would be to point out a commit which
> broke things and put it in a Fixes tag. Much easier to validate a fix
> by looking at where things went wrong.

Thanks, I now looked at some history.

The following commit on 28 Sep 2020 put the kfree call before NULLing:
c8cb5b854b40 ("nl80211/cfg80211: support 6 GHz scanning")

The following commit on 19 Nov 2014 introduces RCU:
6ea0a69ca21b ("mac80211: rcu-ify scan and scheduled scan request pointers")

The kfree call wasn't "rcu-ified" in this commit, and neither were
RCU heads added.

The following commit on 18 Dec 2014 added RCU head for sched_scan_req:
31a60ed1e95a ("nl80211: Convert sched_scan_req pointer to RCU pointer")

It seems a similar thing might not have been done for scan_req, but I
could have also missed commits.

So what should go into the fixes tag, if any? Probably 6ea0a69ca21b?

Also, I probably should use RCU_INIT_POINTER in this patch. Or should
I make a patch somewhat like 31a60ed1e95a?

Thanks,
Siddh
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Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees

  reply	other threads:[~2022-08-13 16:20 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-26 12:39 [PATCH v2] wifi: cfg80211: Fix UAF in ieee80211_scan_rx() Siddh Raman Pant
2022-07-26 12:39 ` Siddh Raman Pant via Linux-kernel-mentees
2022-08-12  9:51 ` Siddh Raman Pant
2022-08-12  9:51   ` Siddh Raman Pant via Linux-kernel-mentees
2022-08-12 12:15   ` Greg KH
2022-08-12 12:15     ` Greg KH
2022-08-12 14:33     ` Siddh Raman Pant
2022-08-12 14:33       ` Siddh Raman Pant via Linux-kernel-mentees
2022-08-12 15:27       ` Greg KH
2022-08-12 15:27         ` Greg KH
2022-08-12 16:27         ` Siddh Raman Pant
2022-08-12 16:27           ` Siddh Raman Pant via Linux-kernel-mentees
2022-08-12 19:25           ` Jakub Kicinski
2022-08-12 19:25             ` Jakub Kicinski
2022-08-13 16:19             ` Siddh Raman Pant [this message]
2022-08-13 16:19               ` Siddh Raman Pant via Linux-kernel-mentees
2022-08-15 16:47               ` Jakub Kicinski
2022-08-15 19:58                 ` Johannes Berg
2022-08-15 19:58                   ` Johannes Berg
2022-08-16  0:51                   ` Jakub Kicinski
2022-08-16  8:52                   ` Siddh Raman Pant via Linux-kernel-mentees
2022-08-16  8:52                     ` Siddh Raman Pant

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