From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Stephan Gerhold <stephan@gerhold.net>
Cc: "David S. Miller" <davem@davemloft.net>,
"Clément Perrochaud" <clement.perrochaud@effinnov.com>,
"Charles Gorand" <charles.gorand@effinnov.com>,
linux-nfc@lists.01.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org,
"Sedat Dilek" <sedat.dilek@credativ.de>
Subject: Re: [PATCH] NFC: nxp-nci: Fix NULL pointer dereference after I2C communication error
Date: Mon, 11 Nov 2019 10:43:43 +0200 [thread overview]
Message-ID: <20191111084343.GM32742@smile.fi.intel.com> (raw)
In-Reply-To: <20191110161915.11059-1-stephan@gerhold.net>
On Sun, Nov 10, 2019 at 05:19:15PM +0100, Stephan Gerhold wrote:
> I2C communication errors (-EREMOTEIO) during the IRQ handler of nxp-nci
> result in a NULL pointer dereference at the moment:
>
> BUG: kernel NULL pointer dereference, address: 0000000000000000
> Oops: 0002 [#1] PREEMPT SMP NOPTI
> CPU: 1 PID: 355 Comm: irq/137-nxp-nci Not tainted 5.4.0-rc6 #1
> RIP: 0010:skb_queue_tail+0x25/0x50
> Call Trace:
> nci_recv_frame+0x36/0x90 [nci]
> nxp_nci_i2c_irq_thread_fn+0xd1/0x285 [nxp_nci_i2c]
> ? preempt_count_add+0x68/0xa0
> ? irq_forced_thread_fn+0x80/0x80
> irq_thread_fn+0x20/0x60
> irq_thread+0xee/0x180
> ? wake_threads_waitq+0x30/0x30
> kthread+0xfb/0x130
> ? irq_thread_check_affinity+0xd0/0xd0
> ? kthread_park+0x90/0x90
> ret_from_fork+0x1f/0x40
>
> Afterward the kernel must be rebooted to work properly again.
>
> This happens because it attempts to call nci_recv_frame() with skb == NULL.
> However, unlike nxp_nci_fw_recv_frame(), nci_recv_frame() does not have any
> NULL checks for skb, causing the NULL pointer dereference.
>
> Change the code to call only nxp_nci_fw_recv_frame() in case of an error.
> Make sure to log it so it is obvious that a communication error occurred.
> The error above then becomes:
>
> nxp-nci_i2c i2c-NXP1001:00: NFC: Read failed with error -121
> nci: __nci_request: wait_for_completion_interruptible_timeout failed 0
> nxp-nci_i2c i2c-NXP1001:00: NFC: Read failed with error -121
>
FWIW,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Fixes: 6be88670fc59 ("NFC: nxp-nci_i2c: Add I2C support to NXP NCI driver")
> Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
> ---
> Note: Not sure why NFC is broken on this laptop (a Lenovo ThinkPad L490).
> It runs into the I2C communication errors immediately when enabling NFC.
> This patch fixes the NULL pointer dereference at least.
> ---
> drivers/nfc/nxp-nci/i2c.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/nfc/nxp-nci/i2c.c b/drivers/nfc/nxp-nci/i2c.c
> index 307bd2afbe05..4d1909aecd6c 100644
> --- a/drivers/nfc/nxp-nci/i2c.c
> +++ b/drivers/nfc/nxp-nci/i2c.c
> @@ -220,8 +220,10 @@ static irqreturn_t nxp_nci_i2c_irq_thread_fn(int irq, void *phy_id)
>
> if (r == -EREMOTEIO) {
> phy->hard_fault = r;
> - skb = NULL;
> - } else if (r < 0) {
> + if (info->mode == NXP_NCI_MODE_FW)
> + nxp_nci_fw_recv_frame(phy->ndev, NULL);
> + }
> + if (r < 0) {
> nfc_err(&client->dev, "Read failed with error %d\n", r);
> goto exit_irq_handled;
> }
> --
> 2.23.0
>
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2019-11-11 8:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-10 16:19 [PATCH] NFC: nxp-nci: Fix NULL pointer dereference after I2C communication error Stephan Gerhold
2019-11-11 8:43 ` Andy Shevchenko [this message]
2019-11-12 5:42 ` David Miller
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