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[198.0.35.241]) by smtp.gmail.com with ESMTPSA id e3-20020a170902b78300b001b88af04175sm1522076pls.41.2023.07.20.08.15.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Jul 2023 08:15:13 -0700 (PDT) From: Kees Cook To: Hans de Goede Cc: Kees Cook , Larry Finger , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH] vboxsf: Use flexible arrays for trailing string member Date: Thu, 20 Jul 2023 08:15:06 -0700 Message-Id: <20230720151458.never.673-kees@kernel.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1230; i=keescook@chromium.org; h=from:subject:message-id; bh=FPWlWMLBWLQk41wEHtF9Aoh4CSJCJMajyADIdaljriw=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBkuU96kJssYE7C3IMQG/og8R3QooDvyV0Ltszxl wFYSldLCqGJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCZLlPegAKCRCJcvTf3G3A Jv+KD/4mMkxhrBH89W97Tm+qKvrzrmOjhG0Y4dB0j6sgNitbBZxCAFMdTAMSXNeK7c6MG8rpk0m u8Aq/XYopofblby5FeWyYmYKtxr6fMn0yifFAPOwlv/Y/k0UGAm9KmteX9xrEg/+sL+tH9vDH52 4PJTLar11KucciW4cdPPWQqdp4nY9H+ONRbKRycWlIXjP4HXFMsU07MioErLoIzJM73VLDOr2nt FQQEk5M6q+zmwIsdzheUle0/b79f12dbkD81rEVvFmXv+5mYpBU4tPZyCFEs+CqsjIJENYwGoFM F2jkyVp9T6HdBonaiqRRv8++PcExWotGJrHVXeb6tZTtJ+xiUHaHVAO2dbFTCGD8Oq1Qxj8LSR2 XdEndk3wVvPqs/5hiQB/9hxeL2GRlHBlrvzMvOVG7Ofn3mvpojtAmQbLD9guxt3u/BEXnrLqqxK RCESTcBs5Lcy0EcYRBCACtjztpkxF16dwE794hUChM7rxTtdrp2vMEFhPsXxoKgoakdlGbsZDfp GgIeLFk5+spiGqODrZXQjQYoLD1vWQdWdEXcdENVN8qddA/cQMMK1kGSgCgso0zl+mvUm+AuLtc gtVSOQInlTRfeUsrzoTCCdJi+uvbi4iB2EFYCPWMn76WNSbwb0Z+5zZ/ThQnDRg0h6OPNDe62vm FV/WbHK fCuhPHJQ== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org The declaration of struct shfl_string used trailing fake flexible arrays for the string member. This was tripping FORTIFY_SOURCE since commit df8fc4e934c1 ("kbuild: Enable -fstrict-flex-arrays=3"). Replace the utf8 and utf16 members with actual flexible arrays, drop the unused ucs2 member, and retriain a 2 byte padding to keep the structure size the same. Reported-by: Larry Finger Closes: https://lore.kernel.org/lkml/ab3a70e9-60ed-0f13-e3d4-8866eaccc8c1@lwfinger.net/ Tested-by: Larry Finger Signed-off-by: Kees Cook --- fs/vboxsf/shfl_hostintf.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/vboxsf/shfl_hostintf.h b/fs/vboxsf/shfl_hostintf.h index aca829062c12..069a019c9247 100644 --- a/fs/vboxsf/shfl_hostintf.h +++ b/fs/vboxsf/shfl_hostintf.h @@ -68,9 +68,9 @@ struct shfl_string { /** UTF-8 or UTF-16 string. Nul terminated. */ union { - u8 utf8[2]; - u16 utf16[1]; - u16 ucs2[1]; /* misnomer, use utf16. */ + u8 legacy_padding[2]; + DECLARE_FLEX_ARRAY(u8, utf8); + DECLARE_FLEX_ARRAY(u16, utf16); } string; }; VMMDEV_ASSERT_SIZE(shfl_string, 6); -- 2.34.1