Re: [GIT PULL] USB fixes for 5.9-rc3

Andy Shevchenko
2020-08-26T15:53:33Z

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On Wed, Aug 26, 2020 at 6:36 PM Greg KH <gregkh@linuxfoundation.org> wrote:
> On Wed, Aug 26, 2020 at 05:02:38PM +0200, Marek Szyprowski wrote:
> > On 26.08.2020 15:43, Greg KH wrote:

> > > Brooke Basile (2):
> > > USB: gadget: u_f: add overflow checks to VLA macros
> >
> > Sorry, but the above patch breaks USB Ethernet Gadget operation. It also
> > didn't get the proper testing in linux-next (next-20200826 is the first
> > one with this patch).
> >
> > This is how it explodes on Samsung Exynos (ARM 32bit) based board with
> > g_ether module loaded:

> Odd, for a "normal" descriptor, the logic should have remained the same
> as without this patch.

> Brooke, any ideas?

I have an idea.

Does below fix this?

--
With Best Regards,
Andy Shevchenko

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diff --git a/drivers/usb/gadget/u_f.h b/drivers/usb/gadget/u_f.h
index df4e1dcb357d..0b5c5f0dd073 100644
--- a/drivers/usb/gadget/u_f.h
+++ b/drivers/usb/gadget/u_f.h
@@ -25,8 +25,8 @@
size_t offset = 0; \
if (groupname##__next != SIZE_MAX) { \
size_t align_mask = __alignof__(type) - 1; \
- size_t offset = (groupname##__next + align_mask) \
- & ~align_mask; \
+ offset = (groupname##__next + align_mask) & \
+ ~align_mask; \
size_t size = array_size(n, sizeof(type)); \
if (check_add_overflow(offset, size, \
&groupname##__next)) { \
@@ -43,8 +43,8 @@
size_t offset = 0; \
if (groupname##__next != SIZE_MAX) { \
size_t align_mask = __alignof__(type) - 1; \
- size_t offset = (groupname##__next + align_mask) \
- & ~align_mask; \
+ offset = (groupname##__next + align_mask) & \
+ ~align_mask; \
if (check_add_overflow(offset, groupname##_##name##__sz,\
&groupname##__next)) { \
groupname##__next = SIZE_MAX; \