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[198.0.35.241]) by smtp.gmail.com with ESMTPSA id 2-20020a630b02000000b0051b7d83ff22sm9713553pgl.80.2023.06.13.14.04.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 13 Jun 2023 14:04:05 -0700 (PDT) From: Kees Cook To: Greg Kroah-Hartman Cc: Kees Cook , kernel test robot , kernel test robot , "Gustavo A. R. Silva" , Dan Williams , =?utf-8?b?SsOzIMOBZ2lsYSBCaXRzY2g=?= , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH] usb: ch9: Replace 1-element array with flexible array Date: Tue, 13 Jun 2023 14:04:04 -0700 Message-Id: <20230613210400.never.078-kees@kernel.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1428; h=from:subject:message-id; bh=JnLkH4pmZPr+c0qLV33G9jBQkGYO6fWW64bmkRy4SIY=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBkiNnDHBwR1Ie8fRBd7eHhD8fIQtVxLvTp5alQtuBH DWwFQ8+JAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCZIjZwwAKCRCJcvTf3G3AJsFCD/ 4x1nXqX6El0WiD6bCA9teDACqjOpqTmk7gcwUI9PdJzVcHeJrbFFtmwxJ9gFMI26Ez67hVKTcXf1di tls62NokgUH9nDlkOUyA3GiEkC8ltgIwI0LHUxeY+Wd9rFiN/f2xceF1pQocUGQ8RdrllXpFObeXKO vq8LBMV6Vv8mnY1xjf/3uS+bNlmcb/TzoeaUGKuwUTJUryRwEnP+IhjjhiLoKq/xVLYinuUPnC3mZ0 VAekizBZYNPHWItfimEw5qQYAR+3GQU2yHhLgOCqXffbmYPIEsElbUK7zun6tPn5F/eMEbcqclBmnL uPSr7hHjqn47v/iuYyXW0XbuxyLrwmJ9BhB7rmfionI+Wo09ttk03hc7IQXzjcpR5frONcP/3DiGn0 G0syov5rKbYlVlxjgUpUZxzs4owZAWVHJdD4fz9ik+qsv6/87Rgos42x+sM+GP/tDIQNmvIxTOGtqb 2YYPNlIP97Y/9zZ9O7b+Z+H1MgJU566fTTcQS9Z2a8ucWzJcXGxnVURF3UlHs+6JP9AzQp3RBCGCpL DMMkA8C1LDWlWMuKfgiCvuBNkX03/Nz4pR7MhEZoWRdqwnOgZq9NOv3yFo4q5l1P4Z5HFlrPY6XPGJ CZxVwukYn6Hzl3Zhl0SrGCQ//moINSF/AnPh2j+2TSVHTIMnlwoLq8KD4B9w== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org With "-fstrict-flex-arrays=3" enabled, UBSAN_BOUNDS no longer pretends 1-element arrays are unbounded. Walking wData 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. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202306102333.8f5a7443-oliver.sang@intel.com Fixes: df8fc4e934c1 ("kbuild: Enable -fstrict-flex-arrays=3") Cc: Greg Kroah-Hartman Cc: kernel test robot Cc: "Gustavo A. R. Silva" Cc: Dan Williams Cc: "Jó Ágila Bitsch" Signed-off-by: Kees Cook Reviewed-by: Gustavo A. R. Silva --- include/uapi/linux/usb/ch9.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/usb/ch9.h b/include/uapi/linux/usb/ch9.h index b17e3a21b15f..82ec6af71a1d 100644 --- a/include/uapi/linux/usb/ch9.h +++ b/include/uapi/linux/usb/ch9.h @@ -376,7 +376,10 @@ struct usb_string_descriptor { __u8 bLength; __u8 bDescriptorType; - __le16 wData[1]; /* UTF-16LE encoded */ + union { + __le16 legacy_padding; + __DECLARE_FLEX_ARRAY(__le16, wData); /* UTF-16LE encoded */ + }; } __attribute__ ((packed)); /* note that "string" zero is special, it holds language codes that