[PATCH v2 -next] tty: ipwireless: Fix potential NULL pointer dereference

[PATCH v2 -next] tty: ipwireless: Fix potential NULL pointer dereference

[YueHaibing]

There is a potential NULL pointer dereference in case
alloc_ctrl_packet() fails and returns NULL.

Fixes: 099dc4fb6265 ("ipwireless: driver for PC Card 3G/UMTS modem")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
---
v2: fix return value
---
 drivers/tty/ipwireless/hardware.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/tty/ipwireless/hardware.c b/drivers/tty/ipwireless/hardware.c
index b0baa4c..1e21ae3 100644
--- a/drivers/tty/ipwireless/hardware.c
+++ b/drivers/tty/ipwireless/hardware.c
@@ -1516,6 +1516,8 @@ static void ipw_send_setup_packet(struct ipw_hardware *hw)
 			sizeof(struct ipw_setup_get_version_query_packet),
 			ADDR_SETUP_PROT, TL_PROTOCOLID_SETUP,
 			TL_SETUP_SIGNO_GET_VERSION_QRY);
+	if (!ver_packet)
+		return;
 	ver_packet->header.length = sizeof(struct tl_setup_get_version_qry);
 
 	/*
-- 
2.7.0

Re: [PATCH v2 -next] tty: ipwireless: Fix potential NULL pointer dereference

[Jiri Slaby]

On 30. 01. 19, 11:30, YueHaibing wrote:
> There is a potential NULL pointer dereference in case
> alloc_ctrl_packet() fails and returns NULL.
> 
> Fixes: 099dc4fb6265 ("ipwireless: driver for PC Card 3G/UMTS modem")
> Signed-off-by: YueHaibing <yuehaibing@huawei.com>
> ---
> v2: fix return value
> ---
>  drivers/tty/ipwireless/hardware.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/tty/ipwireless/hardware.c b/drivers/tty/ipwireless/hardware.c
> index b0baa4c..1e21ae3 100644
> --- a/drivers/tty/ipwireless/hardware.c
> +++ b/drivers/tty/ipwireless/hardware.c
> @@ -1516,6 +1516,8 @@ static void ipw_send_setup_packet(struct ipw_hardware *hw)
>  			sizeof(struct ipw_setup_get_version_query_packet),
>  			ADDR_SETUP_PROT, TL_PROTOCOLID_SETUP,
>  			TL_SETUP_SIGNO_GET_VERSION_QRY);
> +	if (!ver_packet)
> +		return;

LGTM, the timer will retry 30 times, ticking every second.

Acked-by: Jiri Slaby <jslaby@suse.cz>

-- 
js
suse labs

Re: [PATCH v2 -next] tty: ipwireless: Fix potential NULL pointer dereference

[David Sterba]

On Wed, Jan 30, 2019 at 04:58:30PM +0100, Jiri Slaby wrote:
> On 30. 01. 19, 11:30, YueHaibing wrote:
> > There is a potential NULL pointer dereference in case
> > alloc_ctrl_packet() fails and returns NULL.
> > 
> > Fixes: 099dc4fb6265 ("ipwireless: driver for PC Card 3G/UMTS modem")
> > Signed-off-by: YueHaibing <yuehaibing@huawei.com>
> > ---
> > v2: fix return value
> > ---
> >  drivers/tty/ipwireless/hardware.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/drivers/tty/ipwireless/hardware.c b/drivers/tty/ipwireless/hardware.c
> > index b0baa4c..1e21ae3 100644
> > --- a/drivers/tty/ipwireless/hardware.c
> > +++ b/drivers/tty/ipwireless/hardware.c
> > @@ -1516,6 +1516,8 @@ static void ipw_send_setup_packet(struct ipw_hardware *hw)
> >  			sizeof(struct ipw_setup_get_version_query_packet),
> >  			ADDR_SETUP_PROT, TL_PROTOCOLID_SETUP,
> >  			TL_SETUP_SIGNO_GET_VERSION_QRY);
> > +	if (!ver_packet)
> > +		return;
> 
> LGTM, the timer will retry 30 times, ticking every second.

This should be mentioned in the changelog though, it's not obvious at
all why just returning after a failure is ok and that the packet will be
resent.

Re: [PATCH v2 -next] tty: ipwireless: Fix potential NULL pointer dereference

[Jiri Slaby]

On 31. 01. 19, 13:32, David Sterba wrote:
> This should be mentioned in the changelog though, it's not obvious at
> all why just returning after a failure is ok and that the packet will be
> resent.

Agreed.

thanks,
-- 
js
suse labs