* [PATCH] HID: debug: check length before copy_to_user()
@ 2018-07-02 23:59 Daniel Rosenberg
2018-07-03 7:50 ` Benjamin Tissoires
2018-07-05 0:47 ` Al Viro
0 siblings, 2 replies; 4+ messages in thread
From: Daniel Rosenberg @ 2018-07-02 23:59 UTC (permalink / raw)
To: Jiri Kosina, Benjamin Tissoires, linux-input
Cc: linux-kernel, kernel-team, Daniel Rosenberg, stable
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
---
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
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] HID: debug: check length before copy_to_user()
2018-07-02 23:59 [PATCH] HID: debug: check length before copy_to_user() Daniel Rosenberg
@ 2018-07-03 7:50 ` Benjamin Tissoires
2018-07-03 9:55 ` Jiri Kosina
2018-07-05 0:47 ` Al Viro
1 sibling, 1 reply; 4+ messages in thread
From: Benjamin Tissoires @ 2018-07-03 7:50 UTC (permalink / raw)
To: Daniel Rosenberg
Cc: Jiri Kosina, open list:HID CORE LAYER, lkml, kernel-team, 3.8+
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
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] HID: debug: check length before copy_to_user()
2018-07-03 7:50 ` Benjamin Tissoires
@ 2018-07-03 9:55 ` Jiri Kosina
0 siblings, 0 replies; 4+ messages in thread
From: Jiri Kosina @ 2018-07-03 9:55 UTC (permalink / raw)
To: Benjamin Tissoires
Cc: Daniel Rosenberg, open list:HID CORE LAYER, lkml, kernel-team,
3.8+
On Tue, 3 Jul 2018, Benjamin Tissoires 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>
Indeed, thanks a lot for fixing this. Now queued, I'll push it for 4.18.
--
Jiri Kosina
SUSE Labs
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] HID: debug: check length before copy_to_user()
2018-07-02 23:59 [PATCH] HID: debug: check length before copy_to_user() Daniel Rosenberg
2018-07-03 7:50 ` Benjamin Tissoires
@ 2018-07-05 0:47 ` Al Viro
1 sibling, 0 replies; 4+ messages in thread
From: Al Viro @ 2018-07-05 0:47 UTC (permalink / raw)
To: Daniel Rosenberg
Cc: Jiri Kosina, Benjamin Tissoires, linux-input, linux-kernel,
kernel-team, stable
On Mon, Jul 02, 2018 at 04:59:37PM -0700, Daniel Rosenberg wrote:
> If our length is greater than the size of the buffer, we
> overflow the buffer
Hmm...
How about this:
buf = list->hid_debug_buf;
if (list->tail < list->head) {
ret = simple_read_from_buffer(buffer, count, &list->head,
buf, HID_DEBUG_BUFSIZE);
if (ret < 0)
break;
if (list->head != buf + HID_DEBUG_BUFSIZE)
break;
list->head = 0;
}
n = simple_read_from_buffer(buffer + ret, count - ret, &list->head,
buf, list->tail);
if (n >= 0)
ret += n;
if (list->head == buf + HID_DEBUG_BUFSIZE)
list->head = 0;
instead?
^ permalink raw reply [flat|nested] 4+ messages in thread
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2018-07-02 23:59 [PATCH] HID: debug: check length before copy_to_user() Daniel Rosenberg
2018-07-03 7:50 ` Benjamin Tissoires
2018-07-03 9:55 ` Jiri Kosina
2018-07-05 0:47 ` Al Viro
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