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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id r10sm4624434pff.7.2021.08.17.23.05.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Aug 2021 23:05:58 -0700 (PDT) From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Kees Cook , "Gustavo A. R. Silva" , Greg Kroah-Hartman , Andrew Morton , linux-wireless@vger.kernel.org, netdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-staging@lists.linux.dev, linux-block@vger.kernel.org, linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com, Rasmus Villemoes , linux-hardening@vger.kernel.org Subject: [PATCH v2 28/63] fortify: Explicitly disable Clang support Date: Tue, 17 Aug 2021 23:04:58 -0700 Message-Id: <20210818060533.3569517-29-keescook@chromium.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210818060533.3569517-1-keescook@chromium.org> References: <20210818060533.3569517-1-keescook@chromium.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1427; h=from:subject; bh=MScHo/g3fAm2U5yn8644/6JAGaRCvw+x4s3NMxUkYP4=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBhHKMkDmaoP7/LrBvrUTwAq8PIwkOtE8yNEb1/iGaE eotqJxGJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCYRyjJAAKCRCJcvTf3G3AJvkeD/ wK2I9wXb6VkTqNx8ve7VdNSMmlz+1i164ClH9CGR/35x6hLdSQ8qayX0H9g6LrgzVflJDSu0VPqZq6 B60wT0GUsaN+NPYsGb2bVu1Rg3uumqZGiK90AHNJmSYkYU2G3Fqfi/WbeuSh9MygcOeGp/a9x/PQH5 e8dULezGq6dCpC7cs5Zl3okkhjEBCJNG2UsDzKuR/shPokEXvmczONNPE0wD9SGKoJlCrtTATmKvin 4tu2+3vQYizkssvftVjPL/zU+2R6x89hzrj96XdH+uAmeG5P820sWztifwnAHNcLVL5gq7wUOMrJ+f Z4XjIAC/G5EaSS4AhVIu9sD/iX8aeWmFJWF/Y21WLVPcvT0CbToC2WmKfl6Cf/5cmduks3BDmUc73D LWQ9JncTl44MKCvuBhARaFmlaFAJHnLG2EvjMIRi62WS27zMVn6Had7IAo/qffp70xB+LqBNwHlEFR 1DOf7RDGukFMS2YPB64C7srE0otlJasITjwoT2VlC8SUubfSWf2Xs29w2K9ID2LufJo4jW+DES/y1x In7sKpTi8O1ywlBFrMpRGpBZemeuMVX+n2a4KW0Dlmr8PJZVEczotW0P4mEO8JYhohZFLrpQR/oM0d v1l42WB3iKEQLRJlt/B8Os8r3w8Ad46AyHq8GE3PhyPABlRRPciSKq8TGApQ== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Clang has never correctly compiled the FORTIFY_SOURCE defenses due to a couple bugs: Eliding inlines with matching __builtin_* names https://bugs.llvm.org/show_bug.cgi?id=50322 Incorrect __builtin_constant_p() of some globals https://bugs.llvm.org/show_bug.cgi?id=41459 In the process of making improvements to the FORTIFY_SOURCE defenses, the first (silent) bug (coincidentally) becomes worked around, but exposes the latter which breaks the build. As such, Clang must not be used with CONFIG_FORTIFY_SOURCE until at least latter bug is fixed (in Clang 13), and the fortify routines have been rearranged. Update the Kconfig to reflect the reality of the current situation. Signed-off-by: Kees Cook --- security/Kconfig | 3 +++ 1 file changed, 3 insertions(+) diff --git a/security/Kconfig b/security/Kconfig index 0ced7fd33e4d..fe6c0395fa02 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -191,6 +191,9 @@ config HARDENED_USERCOPY_PAGESPAN config FORTIFY_SOURCE bool "Harden common str/mem functions against buffer overflows" depends on ARCH_HAS_FORTIFY_SOURCE + # https://bugs.llvm.org/show_bug.cgi?id=50322 + # https://bugs.llvm.org/show_bug.cgi?id=41459 + depends on !CC_IS_CLANG help Detect overflows of buffers in common string and memory functions where the compiler can determine and validate the buffer sizes.