| Message ID | 20230629190900.never.787-kees@kernel.org (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 01f23c5f1526f5b6ff744887aa511b9e69d4401b |
| Headers | show |
| Series | usb: ch9: Replace bmSublinkSpeedAttr 1-element array with flexible array | expand |
On Thu, Jun 29, 2023 at 12:09:00PM -0700, Kees Cook wrote: > Since commit df8fc4e934c1 ("kbuild: Enable -fstrict-flex-arrays=3"), > UBSAN_BOUNDS no longer pretends 1-element arrays are unbounded. Walking > bmSublinkSpeedAttr will trigger a warning, so make it a proper flexible > array. Add a union to keep the struct size identical for userspace in > case anything was depending on the old size. > > False positive warning was: > > UBSAN: array-index-out-of-bounds in drivers/usb/host/xhci-hub.c:231:31 index 1 is out of range for type '__le32 [1]' > > for this line of code: > > ssp_cap->bmSublinkSpeedAttr[offset++] = cpu_to_le32(attr); > > Reported-by: Borislav Petkov <bp@alien8.de> > Closes: https://lore.kernel.org/lkml/2023062945-fencing-pebble-0411@gregkh/ > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > include/uapi/linux/usb/ch9.h | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) Thanks for the quick response, I'll queue it up after 6.5-rc1 is out. Boris, can you test if this fixes the issue you see or not? greg k-h
On 6/29/23 13:09, Kees Cook wrote: > Since commit df8fc4e934c1 ("kbuild: Enable -fstrict-flex-arrays=3"), > UBSAN_BOUNDS no longer pretends 1-element arrays are unbounded. Walking > bmSublinkSpeedAttr will trigger a warning, so make it a proper flexible > array. Add a union to keep the struct size identical for userspace in > case anything was depending on the old size. > > False positive warning was: > > UBSAN: array-index-out-of-bounds in drivers/usb/host/xhci-hub.c:231:31 index 1 is out of range for type '__le32 [1]' > > for this line of code: > > ssp_cap->bmSublinkSpeedAttr[offset++] = cpu_to_le32(attr); > > Reported-by: Borislav Petkov <bp@alien8.de> > Closes: https://lore.kernel.org/lkml/2023062945-fencing-pebble-0411@gregkh/ > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> > Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> Thanks! -- Gustavo > --- > include/uapi/linux/usb/ch9.h | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/include/uapi/linux/usb/ch9.h b/include/uapi/linux/usb/ch9.h > index b17e3a21b15f..3ff98c7ba7e3 100644 > --- a/include/uapi/linux/usb/ch9.h > +++ b/include/uapi/linux/usb/ch9.h > @@ -981,7 +981,11 @@ struct usb_ssp_cap_descriptor { > #define USB_SSP_MIN_RX_LANE_COUNT (0xf << 8) > #define USB_SSP_MIN_TX_LANE_COUNT (0xf << 12) > __le16 wReserved; > - __le32 bmSublinkSpeedAttr[1]; /* list of sublink speed attrib entries */ > + union { > + __le32 legacy_padding; > + /* list of sublink speed attrib entries */ > + __DECLARE_FLEX_ARRAY(__le32, bmSublinkSpeedAttr); > + }; > #define USB_SSP_SUBLINK_SPEED_SSID (0xf) /* sublink speed ID */ > #define USB_SSP_SUBLINK_SPEED_LSE (0x3 << 4) /* Lanespeed exponent */ > #define USB_SSP_SUBLINK_SPEED_LSE_BPS 0
On Thu, Jun 29, 2023 at 09:17:23PM +0200, Greg Kroah-Hartman wrote: > Boris, can you test if this fixes the issue you see or not? Tested-by: Borislav Petkov (AMD) <bp@alien8.de>
On Thu, Jun 29, 2023 at 09:17:23PM +0200, Greg Kroah-Hartman wrote: > On Thu, Jun 29, 2023 at 12:09:00PM -0700, Kees Cook wrote: > > Since commit df8fc4e934c1 ("kbuild: Enable -fstrict-flex-arrays=3"), > > UBSAN_BOUNDS no longer pretends 1-element arrays are unbounded. Walking > > bmSublinkSpeedAttr will trigger a warning, so make it a proper flexible > > array. Add a union to keep the struct size identical for userspace in > > case anything was depending on the old size. > > > > False positive warning was: > > > > UBSAN: array-index-out-of-bounds in drivers/usb/host/xhci-hub.c:231:31 index 1 is out of range for type '__le32 [1]' > > > > for this line of code: > > > > ssp_cap->bmSublinkSpeedAttr[offset++] = cpu_to_le32(attr); > > > > Reported-by: Borislav Petkov <bp@alien8.de> > > Closes: https://lore.kernel.org/lkml/2023062945-fencing-pebble-0411@gregkh/ > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> > > Signed-off-by: Kees Cook <keescook@chromium.org> > > --- > > include/uapi/linux/usb/ch9.h | 6 +++++- > > 1 file changed, 5 insertions(+), 1 deletion(-) > > Thanks for the quick response, I'll queue it up after 6.5-rc1 is out. I'm going to send this before -rc1, since we've had another report[1] that was fixed by this. Given the verification there and Boris's testing, I think this is good to land. I'll toss it in -next now and send it to Linus on Friday after making sure there are no more surprises. -Kees [1] https://lore.kernel.org/lkml/DA3FEB08-DF39-406B-89CC-9076CFCF597A@kernel.org/
On Wed, Jul 05, 2023 at 02:11:03PM -0700, Kees Cook wrote: > On Thu, Jun 29, 2023 at 09:17:23PM +0200, Greg Kroah-Hartman wrote: > > On Thu, Jun 29, 2023 at 12:09:00PM -0700, Kees Cook wrote: > > > Since commit df8fc4e934c1 ("kbuild: Enable -fstrict-flex-arrays=3"), > > > UBSAN_BOUNDS no longer pretends 1-element arrays are unbounded. Walking > > > bmSublinkSpeedAttr will trigger a warning, so make it a proper flexible > > > array. Add a union to keep the struct size identical for userspace in > > > case anything was depending on the old size. > > > > > > False positive warning was: > > > > > > UBSAN: array-index-out-of-bounds in drivers/usb/host/xhci-hub.c:231:31 index 1 is out of range for type '__le32 [1]' > > > > > > for this line of code: > > > > > > ssp_cap->bmSublinkSpeedAttr[offset++] = cpu_to_le32(attr); > > > > > > Reported-by: Borislav Petkov <bp@alien8.de> > > > Closes: https://lore.kernel.org/lkml/2023062945-fencing-pebble-0411@gregkh/ > > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > > Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> > > > Signed-off-by: Kees Cook <keescook@chromium.org> > > > --- > > > include/uapi/linux/usb/ch9.h | 6 +++++- > > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > Thanks for the quick response, I'll queue it up after 6.5-rc1 is out. > > I'm going to send this before -rc1, since we've had another report[1] that > was fixed by this. Given the verification there and Boris's testing, I > think this is good to land. I'll toss it in -next now and send it to > Linus on Friday after making sure there are no more surprises. > > -Kees > > [1] https://lore.kernel.org/lkml/DA3FEB08-DF39-406B-89CC-9076CFCF597A@kernel.org/ No problem: Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/uapi/linux/usb/ch9.h b/include/uapi/linux/usb/ch9.h index b17e3a21b15f..3ff98c7ba7e3 100644 --- a/include/uapi/linux/usb/ch9.h +++ b/include/uapi/linux/usb/ch9.h @@ -981,7 +981,11 @@ struct usb_ssp_cap_descriptor { #define USB_SSP_MIN_RX_LANE_COUNT (0xf << 8) #define USB_SSP_MIN_TX_LANE_COUNT (0xf << 12) __le16 wReserved; - __le32 bmSublinkSpeedAttr[1]; /* list of sublink speed attrib entries */ + union { + __le32 legacy_padding; + /* list of sublink speed attrib entries */ + __DECLARE_FLEX_ARRAY(__le32, bmSublinkSpeedAttr); + }; #define USB_SSP_SUBLINK_SPEED_SSID (0xf) /* sublink speed ID */ #define USB_SSP_SUBLINK_SPEED_LSE (0x3 << 4) /* Lanespeed exponent */ #define USB_SSP_SUBLINK_SPEED_LSE_BPS 0
Since commit df8fc4e934c1 ("kbuild: Enable -fstrict-flex-arrays=3"), UBSAN_BOUNDS no longer pretends 1-element arrays are unbounded. Walking bmSublinkSpeedAttr will trigger a warning, so make it a proper flexible array. Add a union to keep the struct size identical for userspace in case anything was depending on the old size. False positive warning was: UBSAN: array-index-out-of-bounds in drivers/usb/host/xhci-hub.c:231:31 index 1 is out of range for type '__le32 [1]' for this line of code: ssp_cap->bmSublinkSpeedAttr[offset++] = cpu_to_le32(attr); Reported-by: Borislav Petkov <bp@alien8.de> Closes: https://lore.kernel.org/lkml/2023062945-fencing-pebble-0411@gregkh/ Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> --- include/uapi/linux/usb/ch9.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)