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usb: gadget: f_hid: fixed NULL pointer dereference 

commit 2867652e4766360adf14dfda3832455e04964f2a upstream.

Disconnecting and reconnecting the USB cable can lead to crashes
and a variety of kernel log spam.

The problem was found and reproduced on the Raspberry Pi [1]
and the original fix was created in Raspberry's own fork [2].

Link: https://github.com/raspberrypi/linux/issues/3870 [1]
Link: a6e47d5f4e [2]
Signed-off-by: Maxim Devaev <mdevaev@gmail.com>
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210723155928.210019-1-mdevaev@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Phil Elwell 2021-07-23 18:59:30 +03:00 committed by Greg Kroah-Hartman
parent f780a9580c
commit 02f336cee5
1 changed files with 21 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
drivers/usb/gadget/function/f_hid.c
View File

@ -345,6 +345,11 @@ static ssize_t f_hidg_write(struct file *file, const char __user *buffer,
spin_lock_irqsave(&hidg->write_spinlock, flags);
if (!hidg->req) {
spin_unlock_irqrestore(&hidg->write_spinlock, flags);
return -ESHUTDOWN;
}
#define WRITE_COND (!hidg->write_pending)
try_again:
/* write queue */
@ -365,8 +370,14 @@ try_again:
count = min_t(unsigned, count, hidg->report_length);
spin_unlock_irqrestore(&hidg->write_spinlock, flags);
status = copy_from_user(req->buf, buffer, count);
if (!req) {
ERROR(hidg->func.config->cdev, "hidg->req is NULL\n");
status = -ESHUTDOWN;
goto release_write_pending;
}
status = copy_from_user(req->buf, buffer, count);
if (status != 0) {
ERROR(hidg->func.config->cdev,
"copy_from_user error\n");
@ -394,15 +405,18 @@ try_again:
spin_unlock_irqrestore(&hidg->write_spinlock, flags);
status = usb_ep_queue(hidg->in_ep, req, GFP_ATOMIC);
if (status < 0) {
ERROR(hidg->func.config->cdev,
"usb_ep_queue error on int endpoint %zd\n", status);
if (!hidg->in_ep->enabled) {
ERROR(hidg->func.config->cdev, "in_ep is disabled\n");
status = -ESHUTDOWN;
goto release_write_pending;
} else {
status = count;
}
status = usb_ep_queue(hidg->in_ep, req, GFP_ATOMIC);
if (status < 0)
goto release_write_pending;
else
status = count;
return status;
release_write_pending:
spin_lock_irqsave(&hidg->write_spinlock, flags);