Messages in this thread | | | From | Benjamin Tissoires <> | Date | Tue, 3 Jul 2018 09:50:16 +0200 | Subject | Re: [PATCH] HID: debug: check length before copy_to_user() |
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On Tue, Jul 3, 2018 at 1:59 AM, Daniel Rosenberg <drosen@google.com> wrote: > If our length is greater than the size of the buffer, we > overflow the buffer > > Signed-off-by: Daniel Rosenberg <drosen@google.com> > Cc: stable@vger.kernel.org > ---
Looks good: Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cheers, Benjamin
> drivers/hid/hid-debug.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/hid/hid-debug.c b/drivers/hid/hid-debug.c > index 8469b6964ff64..b48100236df89 100644 > --- a/drivers/hid/hid-debug.c > +++ b/drivers/hid/hid-debug.c > @@ -1154,6 +1154,8 @@ static ssize_t hid_debug_events_read(struct file *file, char __user *buffer, > goto out; > if (list->tail > list->head) { > len = list->tail - list->head; > + if (len > count) > + len = count; > > if (copy_to_user(buffer + ret, &list->hid_debug_buf[list->head], len)) { > ret = -EFAULT; > @@ -1163,6 +1165,8 @@ static ssize_t hid_debug_events_read(struct file *file, char __user *buffer, > list->head += len; > } else { > len = HID_DEBUG_BUFSIZE - list->head; > + if (len > count) > + len = count; > > if (copy_to_user(buffer, &list->hid_debug_buf[list->head], len)) { > ret = -EFAULT; > @@ -1170,7 +1174,9 @@ static ssize_t hid_debug_events_read(struct file *file, char __user *buffer, > } > list->head = 0; > ret += len; > - goto copy_rest; > + count -= len; > + if (count > 0) > + goto copy_rest; > } > > } > -- > 2.18.0.399.gad0ab374a1-goog >
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