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From: "Starke, Daniel" <daniel.starke@siemens.com>
To: Mazin Al Haddad <mazinalhaddad05@gmail.com>
Cc: "jirislaby@kernel.org" <jirislaby@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-kernel-mentees@lists.linuxfoundation.org" 
	<linux-kernel-mentees@lists.linuxfoundation.org>,
	"skhan@linuxfoundation.org" <skhan@linuxfoundation.org>,
	"paskripkin@gmail.com" <paskripkin@gmail.com>,
	"syzbot+e3563f0c94e188366dbb@syzkaller.appspotmail.com" 
	<syzbot+e3563f0c94e188366dbb@syzkaller.appspotmail.com>,
	Greg KH <gregkh@linuxfoundation.org>
Subject: RE: [PATCH] tty: n_gsm: fix missing assignment of gsm->receive() in gsmld_attach_gsm()
Date: Wed, 10 Aug 2022 09:08:13 +0000	[thread overview]
Message-ID: <DB9PR10MB58813E33D3516BAB526156B1E0659@DB9PR10MB5881.EURPRD10.PROD.OUTLOOK.COM> (raw)

> Fix this by setting the gsm->receive() function when the line 
> discipline is being attached to the terminal device, inside 
> gsmld_attach_gsm(). This will guarantee that the function is assigned 
> and a call to TIOCSTI, which calls gsmld_receive_buf(), will not
> reference a null pointer.

In my opinion there are only two possible ways to fix this:
a) Move the gsm->receive initialization from gsm_activate_mux() to
gsmld_attach_gsm().
b) Avoid calling gsm->receive in gsmld_receive_buf() if not initialized.

The current code might assume that gsm->receive is only called after MUX
activation. Therefore, variant a) may break the code in other places.
I see no need to initialize gsm->receive in gsm_activate_mux() and
gsmld_attach_gsm().

Best regards,
Daniel Starke

WARNING: multiple messages have this Message-ID (diff)
From: "Starke, Daniel" <daniel.starke@siemens.com>
To: Mazin Al Haddad <mazinalhaddad05@gmail.com>
Cc: "jirislaby@kernel.org" <jirislaby@kernel.org>,
	"paskripkin@gmail.com" <paskripkin@gmail.com>,
	"syzbot+e3563f0c94e188366dbb@syzkaller.appspotmail.com"
	<syzbot+e3563f0c94e188366dbb@syzkaller.appspotmail.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-kernel-mentees@lists.linuxfoundation.org"
	<linux-kernel-mentees@lists.linuxfoundation.org>
Subject: RE: [PATCH] tty: n_gsm: fix missing assignment of gsm->receive() in gsmld_attach_gsm()
Date: Wed, 10 Aug 2022 09:08:13 +0000	[thread overview]
Message-ID: <DB9PR10MB58813E33D3516BAB526156B1E0659@DB9PR10MB5881.EURPRD10.PROD.OUTLOOK.COM> (raw)

> Fix this by setting the gsm->receive() function when the line 
> discipline is being attached to the terminal device, inside 
> gsmld_attach_gsm(). This will guarantee that the function is assigned 
> and a call to TIOCSTI, which calls gsmld_receive_buf(), will not
> reference a null pointer.

In my opinion there are only two possible ways to fix this:
a) Move the gsm->receive initialization from gsm_activate_mux() to
gsmld_attach_gsm().
b) Avoid calling gsm->receive in gsmld_receive_buf() if not initialized.

The current code might assume that gsm->receive is only called after MUX
activation. Therefore, variant a) may break the code in other places.
I see no need to initialize gsm->receive in gsm_activate_mux() and
gsmld_attach_gsm().

Best regards,
Daniel Starke
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees

             reply	other threads:[~2022-08-10  9:08 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-10  9:08 Starke, Daniel [this message]
2022-08-10  9:08 ` [PATCH] tty: n_gsm: fix missing assignment of gsm->receive() in gsmld_attach_gsm() Starke, Daniel
2022-08-12 19:41 ` Mazin Al Haddad
2022-08-12 19:41   ` Mazin Al Haddad
  -- strict thread matches above, loose matches on Subject: below --
2022-08-10  3:12 Mazin Al Haddad
2022-08-10  3:12 ` Mazin Al Haddad
2022-08-10  5:18 ` Greg KH
2022-08-10  5:18   ` Greg KH

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