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-rw-r--r--SOURCES/hid-wacom-correct-null-dereference-on-aes-pen-proximity.patch85
1 files changed, 85 insertions, 0 deletions
diff --git a/SOURCES/hid-wacom-correct-null-dereference-on-aes-pen-proximity.patch b/SOURCES/hid-wacom-correct-null-dereference-on-aes-pen-proximity.patch
new file mode 100644
index 0000000..d76b648
--- /dev/null
+++ b/SOURCES/hid-wacom-correct-null-dereference-on-aes-pen-proximity.patch
@@ -0,0 +1,85 @@
+From MAILER-DAEMON Wed Jan 27 14:42:50 2021
+From: Jason Gerecke <killertofu@gmail.com>
+To: linux-input@vger.kernel.org, Jiri Kosina <jikos@kernel.org>, Benjamin Tissoires <benjamin.tissoires@redhat.com>
+Cc: Jason Gerecke <jason.gerecke@wacom.com>, stable@vger.kernel.org, Ping Cheng <ping.cheng@wacom.com>
+Subject: [PATCH] HID: wacom: Correct NULL dereference on AES pen proximity
+Date: Thu, 21 Jan 2021 10:46:49 -0800
+Message-Id: <20210121184649.157189-1-jason.gerecke@wacom.com>
+List-ID: <linux-input.vger.kernel.org>
+X-Mailing-List: linux-input@vger.kernel.org
+MIME-Version: 1.0
+Content-Type: text/plain; charset="utf-8"
+Content-Transfer-Encoding: 7bit
+
+The recent commit to fix a memory leak introduced an inadvertant NULL
+pointer dereference. The `wacom_wac->pen_fifo` variable was never
+intialized, resuling in a crash whenever functions tried to use it.
+Since the FIFO is only used by AES pens (to buffer events from pen
+proximity until the hardware reports the pen serial number) this would
+have been easily overlooked without testing an AES device.
+
+This patch converts `wacom_wac->pen_fifo` over to a pointer (since the
+call to `devres_alloc` allocates memory for us) and ensures that we assign
+it to point to the allocated and initalized `pen_fifo` before the function
+returns.
+
+Fixes: 37309f47e2f5 ("HID: wacom: Fix memory leakage caused by kfifo_alloc")
+Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
+Tested-by: Ping Cheng <ping.cheng@wacom.com>
+CC: stable@vger.kernel.org # v4.19+
+Link: https://github.com/linuxwacom/input-wacom/issues/230
+---
+ drivers/hid/wacom_sys.c | 7 ++++---
+ drivers/hid/wacom_wac.h | 2 +-
+ 2 files changed, 5 insertions(+), 4 deletions(-)
+
+diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c
+index e8acd235db2a..aa9e48876ced 100644
+--- a/drivers/hid/wacom_sys.c
++++ b/drivers/hid/wacom_sys.c
+@@ -147,9 +147,9 @@ static int wacom_wac_pen_serial_enforce(struct hid_device *hdev,
+ }
+
+ if (flush)
+- wacom_wac_queue_flush(hdev, &wacom_wac->pen_fifo);
++ wacom_wac_queue_flush(hdev, wacom_wac->pen_fifo);
+ else if (insert)
+- wacom_wac_queue_insert(hdev, &wacom_wac->pen_fifo,
++ wacom_wac_queue_insert(hdev, wacom_wac->pen_fifo,
+ raw_data, report_size);
+
+ return insert && !flush;
+@@ -1280,7 +1280,7 @@ static void wacom_devm_kfifo_release(struct device *dev, void *res)
+ static int wacom_devm_kfifo_alloc(struct wacom *wacom)
+ {
+ struct wacom_wac *wacom_wac = &wacom->wacom_wac;
+- struct kfifo_rec_ptr_2 *pen_fifo = &wacom_wac->pen_fifo;
++ struct kfifo_rec_ptr_2 *pen_fifo;
+ int error;
+
+ pen_fifo = devres_alloc(wacom_devm_kfifo_release,
+@@ -1297,6 +1297,7 @@ static int wacom_devm_kfifo_alloc(struct wacom *wacom)
+ }
+
+ devres_add(&wacom->hdev->dev, pen_fifo);
++ wacom_wac->pen_fifo = pen_fifo;
+
+ return 0;
+ }
+diff --git a/drivers/hid/wacom_wac.h b/drivers/hid/wacom_wac.h
+index da612b6e9c77..195910dd2154 100644
+--- a/drivers/hid/wacom_wac.h
++++ b/drivers/hid/wacom_wac.h
+@@ -342,7 +342,7 @@ struct wacom_wac {
+ struct input_dev *pen_input;
+ struct input_dev *touch_input;
+ struct input_dev *pad_input;
+- struct kfifo_rec_ptr_2 pen_fifo;
++ struct kfifo_rec_ptr_2 *pen_fifo;
+ int pid;
+ int num_contacts_left;
+ u8 bt_features;
+--
+2.30.0
+
+