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[90.182.112.124]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-49ce4761dd1sm331050675e9.0.2026.09.08.04.30.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Sep 2026 04:30:36 -0700 (PDT) Date: Tue, 8 Sep 2026 13:30:33 +0200 From: Joshua Crofts To: David Heidelberg Cc: oe-linux-nfc@lists.linux.dev, linux-kernel@vger.kernel.org, syzbot+59d5e6a8ed04e6a000c8@syzkaller.appspotmail.com Subject: Re: [PATCH] nfc: nfcmrvl: fix null pointer dereference in nfcmrvl_bulk_complete Message-ID: <20260908133033.000037c5@gmail.com> In-Reply-To: <20260831104110.1307-1-joshua.crofts1@gmail.com> References: <20260831104110.1307-1-joshua.crofts1@gmail.com> X-Mailer: Claws Mail 4.4.0 (GTK 3.24.51; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: oe-linux-nfc@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Mon, 31 Aug 2026 10:41:10 +0000 Joshua Crofts wrote: > A race condition in the current implementation can cause a null pointer > dereference. When nfcmrvl_nci_register_dev() calls nci_register_device(), > the NCI device is immediately exposed to userspace. If userspace brings > up the device before probe() finishes assigning drv_data->priv, > submitted bulk URBs can complete while priv is still NULL. > > Additionally, nfcmrvl_bulk_complete() incorrectly checked > NFCMRVL_NCI_RUNNING on drv_data->flags instead of drv_data->priv->flags. > > Fix this by adding a NULL check and testing NFCMRVL_NCI_RUNNING on > drv_data->priv->flags before processing the completed URB. > > Fixes: f26e30cc6b50 ("NFC: nfcmrvl: Initial commit for Marvell NFC driver") > Reported-by: syzbot+59d5e6a8ed04e6a000c8@syzkaller.appspotmail.com > Closes: https://syzkaller.appspot.com/bug?extid=59d5e6a8ed04e6a000c8 > Tested-by: syzbot+59d5e6a8ed04e6a000c8@syzkaller.appspotmail.com > Signed-off-by: Joshua Crofts > --- > drivers/nfc/nfcmrvl/usb.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/nfc/nfcmrvl/usb.c b/drivers/nfc/nfcmrvl/usb.c > index c7f2afe00b93..c22d783718fe 100644 > --- a/drivers/nfc/nfcmrvl/usb.c > +++ b/drivers/nfc/nfcmrvl/usb.c > @@ -61,7 +61,7 @@ static void nfcmrvl_bulk_complete(struct urb *urb) > dev_dbg(&drv_data->udev->dev, "urb %p status %d count %d\n", > urb, urb->status, urb->actual_length); > > - if (!test_bit(NFCMRVL_NCI_RUNNING, &drv_data->flags)) > + if (!drv_data->priv || !test_bit(NFCMRVL_NCI_RUNNING, &drv_data->priv->flags)) > return; > > if (!urb->status) { Hi David, gentle ping on this patch. -- Kind regards, Joshua Crofts