[PATCH] usb: musb: Fix a possible null-pointer dereference in musb_handle_intr_connect()

[PATCH] usb: musb: Fix a possible null-pointer dereference in musb_handle_intr_connect()

[Jia-Ju Bai]

In musb_handle_intr_connect(), there is an if statement on line 783 to
check whether musb->hcd is NULL:
    if (musb->hcd)

When musb->hcd is NULL, it is used on line 797:
    musb_host_poke_root_hub(musb);
        if (musb->hcd->status_urb)

Thus, a possible null-pointer dereference may occur.

To fix this bug, musb->hcd is checked before calling
musb_host_poke_root_hub().

This bug is found by a static analysis tool STCheck written by us.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
 drivers/usb/musb/musb_core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index 9f5a4819a744..329ff52f8167 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -794,7 +794,8 @@ static void musb_handle_intr_connect(struct musb *musb, u8 devctl, u8 int_usb)
 		break;
 	}
 
-	musb_host_poke_root_hub(musb);
+	if (musb->hcd)
+		musb_host_poke_root_hub(musb);
 
 	musb_dbg(musb, "CONNECT (%s) devctl %02x",
 			usb_otg_state_string(musb->xceiv->otg->state), devctl);
-- 
2.17.0

Re: [PATCH] usb: musb: Fix a possible null-pointer dereference in musb_handle_intr_connect()

[Bin Liu]

On Mon, Jul 29, 2019 at 05:04:28PM +0800, Jia-Ju Bai wrote:
> In musb_handle_intr_connect(), there is an if statement on line 783 to
> check whether musb->hcd is NULL:
>     if (musb->hcd)
> 
> When musb->hcd is NULL, it is used on line 797:
>     musb_host_poke_root_hub(musb);
>         if (musb->hcd->status_urb)
> 
> Thus, a possible null-pointer dereference may occur.
> 
> To fix this bug, musb->hcd is checked before calling
> musb_host_poke_root_hub().
> 
> This bug is found by a static analysis tool STCheck written by us.
> 
> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>

Applied. Thanks.

-Bin.