From: Kees Cook <keescook@chromium.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Kees Cook" <keescook@chromium.org>,
"Borislav Petkov" <bp@alien8.de>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
"Jó Ágila Bitsch" <jgilab@gmail.com>,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: [PATCH] usb: ch9: Replace bmSublinkSpeedAttr 1-element array with flexible array
Date: Thu, 29 Jun 2023 12:09:00 -0700 [thread overview]
Message-ID: <20230629190900.never.787-kees@kernel.org> (raw)
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(-)
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
--
2.34.1
next reply other threads:[~2023-06-29 19:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-29 19:09 Kees Cook [this message]
2023-06-29 19:17 ` [PATCH] usb: ch9: Replace bmSublinkSpeedAttr 1-element array with flexible array Greg Kroah-Hartman
2023-06-30 13:34 ` Borislav Petkov
2023-07-05 21:11 ` Kees Cook
2023-07-06 7:47 ` Greg Kroah-Hartman
2023-06-29 19:22 ` Gustavo A. R. Silva
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