[PATCH 4.18 151/228] usb: core: safely deal with the dynamic quirk lists

From: Greg Kroah-Hartman
Date: Tue Oct 02 2018 - 09:29:37 EST


4.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Harry Pan <harry.pan@xxxxxxxxx>

commit 16c4cb19fa85c648a803752eb63cac0ef69231c2 upstream.

Applying dynamic usbcore quirks in early booting when the slab is
not yet ready would cause kernel panic of null pointer dereference
because the quirk_count has been counted as 1 while the quirk_list
was failed to allocate.

i.e.,
[ 1.044970] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 1.044995] IP: [<ffffffffb0953ec7>] usb_detect_quirks+0x88/0xd1
[ 1.045016] PGD 0
[ 1.045026] Oops: 0000 [#1] PREEMPT SMP
[ 1.046986] gsmi: Log Shutdown Reason 0x03
[ 1.046995] Modules linked in:
[ 1.047008] CPU: 0 PID: 81 Comm: kworker/0:3 Not tainted 4.4.154 #28
[ 1.047016] Hardware name: Google Coral/Coral, BIOS Google_Coral.10068.27.0 12/04/2017
[ 1.047028] Workqueue: usb_hub_wq hub_event
[ 1.047037] task: ffff88017a321c80 task.stack: ffff88017a384000
[ 1.047044] RIP: 0010:[<ffffffffb0953ec7>] [<ffffffffb0953ec7>] usb_detect_quirks+0x88/0xd1

To tackle this odd, let's balance the quirk_count to 0 when the kcalloc
call fails, and defer the quirk setting into a lower level callback
which ensures that the kernel memory management has been initialized.

Fixes: 027bd6cafd9a ("usb: core: Add "quirks" parameter for usbcore")
Signed-off-by: Harry Pan <harry.pan@xxxxxxxxx>
Acked-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/usb/core/quirks.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/usb/core/quirks.c
+++ b/drivers/usb/core/quirks.c
@@ -58,6 +58,7 @@ static int quirks_param_set(const char *
quirk_list = kcalloc(quirk_count, sizeof(struct quirk_entry),
GFP_KERNEL);
if (!quirk_list) {
+ quirk_count = 0;
mutex_unlock(&quirk_mutex);
return -ENOMEM;
}
@@ -154,7 +155,7 @@ static struct kparam_string quirks_param
.string = quirks_param,
};

-module_param_cb(quirks, &quirks_param_ops, &quirks_param_string, 0644);
+device_param_cb(quirks, &quirks_param_ops, &quirks_param_string, 0644);
MODULE_PARM_DESC(quirks, "Add/modify USB quirks by specifying quirks=vendorID:productID:quirks");

/* Lists of quirky USB devices, split in device quirks and interface quirks.