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From: Shayne Chen <shayne.chen@mediatek.com>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: "Toke Høiland-Jørgensen" <toke@toke.dk>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	"Ryder Lee" <ryder.lee@mediatek.com>,
	linux-mediatek <linux-mediatek@lists.infradead.org>,
	"Sujuan Chen" <sujuan.chen@mediatek.com>,
	"Lorenzo Bianconi" <lorenzo.bianconi@redhat.com>,
	"Felix Fietkau" <nbd@nbd.name>
Subject: Re: [PATCH] mac80211: fix incorrect strlen of .write in debugfs
Date: Tue, 12 Jan 2021 09:42:32 +0800	[thread overview]
Message-ID: <1610415752.4985.16.camel@mtksdccf07> (raw)
In-Reply-To: <036e334c2a0a2ebaf940d3f7ae03ab0d9f7c45fb.camel@sipsolutions.net>

On Mon, 2021-01-11 at 13:10 +0100, Johannes Berg wrote:
> On Mon, 2021-01-11 at 14:19 +0800, Shayne Chen wrote:
> > 
> > Regarding the case "10\n\0\0\0\0", both count and strlen() fail to get
> > the correct strlen.
> 
> Yeah.
> 
> I don't think we need to worry about this case.
> 
Got it.
> > # echo "10\n\0\0\0\0" > /sys/kernel/debug/ieee80211/phy0/airtime_flags
> > airtime_flags_write: count = 13, strlen = 15 
> > > > +	buf[count] = '\0';
> > > 
> > > But if count == sizeof(buf) then this is an out-of-bounds write.
> > > 
> > > Same for all the other copied instances.
> > > 
> > > johannes
> > > 
> > 
> > Should we consider this kind of case here?
> 
> Sure, we're at the kernel/userspace trust boundary, we can't just read
> out-of-bounds? Or what do you mean?
> 
> johannes
> 
> 

Sorry, I put the reply in a wrong place.
I meant should we consider the case "10\n\0\0\0\0" here.

Will send v2, thank you.

Shayne
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WARNING: multiple messages have this Message-ID (diff)
From: Shayne Chen <shayne.chen@mediatek.com>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: linux-wireless <linux-wireless@vger.kernel.org>,
	"Toke Høiland-Jørgensen" <toke@toke.dk>,
	"Felix Fietkau" <nbd@nbd.name>,
	"Lorenzo Bianconi" <lorenzo.bianconi@redhat.com>,
	"Ryder Lee" <ryder.lee@mediatek.com>,
	linux-mediatek <linux-mediatek@lists.infradead.org>,
	"Sujuan Chen" <sujuan.chen@mediatek.com>
Subject: Re: [PATCH] mac80211: fix incorrect strlen of .write in debugfs
Date: Tue, 12 Jan 2021 09:42:32 +0800	[thread overview]
Message-ID: <1610415752.4985.16.camel@mtksdccf07> (raw)
In-Reply-To: <036e334c2a0a2ebaf940d3f7ae03ab0d9f7c45fb.camel@sipsolutions.net>

On Mon, 2021-01-11 at 13:10 +0100, Johannes Berg wrote:
> On Mon, 2021-01-11 at 14:19 +0800, Shayne Chen wrote:
> > 
> > Regarding the case "10\n\0\0\0\0", both count and strlen() fail to get
> > the correct strlen.
> 
> Yeah.
> 
> I don't think we need to worry about this case.
> 
Got it.
> > # echo "10\n\0\0\0\0" > /sys/kernel/debug/ieee80211/phy0/airtime_flags
> > airtime_flags_write: count = 13, strlen = 15 
> > > > +	buf[count] = '\0';
> > > 
> > > But if count == sizeof(buf) then this is an out-of-bounds write.
> > > 
> > > Same for all the other copied instances.
> > > 
> > > johannes
> > > 
> > 
> > Should we consider this kind of case here?
> 
> Sure, we're at the kernel/userspace trust boundary, we can't just read
> out-of-bounds? Or what do you mean?
> 
> johannes
> 
> 

Sorry, I put the reply in a wrong place.
I meant should we consider the case "10\n\0\0\0\0" here.

Will send v2, thank you.

Shayne

  reply	other threads:[~2021-01-12  1:45 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-08 10:56 [PATCH] mac80211: fix incorrect strlen of .write in debugfs Shayne Chen
2021-01-08 10:56 ` Shayne Chen
2021-01-08 12:27 ` Toke Høiland-Jørgensen
2021-01-08 12:27   ` Toke Høiland-Jørgensen
2021-01-08 20:02 ` Johannes Berg
2021-01-08 20:02   ` Johannes Berg
2021-01-09  0:22   ` Ryder Lee
2021-01-09  0:22     ` Ryder Lee
2021-01-11  6:19   ` Shayne Chen
2021-01-11  6:19     ` Shayne Chen
2021-01-11 12:10     ` Johannes Berg
2021-01-11 12:10       ` Johannes Berg
2021-01-12  1:42       ` Shayne Chen [this message]
2021-01-12  1:42         ` Shayne Chen

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