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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id k4sm7192916pjg.48.2020.07.31.16.08.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 31 Jul 2020 16:08:44 -0700 (PDT) From: Kees Cook To: Thomas Gleixner , Will Deacon Cc: Kees Cook , Catalin Marinas , Mark Rutland , Ard Biesheuvel , Peter Collingbourne , James Morse , Borislav Petkov , Ingo Molnar , Russell King , Masahiro Yamada , Arvind Sankar , Nick Desaulniers , Nathan Chancellor , Arnd Bergmann , x86@kernel.org, clang-built-linux@googlegroups.com, linux-arch@vger.kernel.org, linux-efi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v5 32/36] x86/boot/compressed: Reorganize zero-size section asserts Date: Fri, 31 Jul 2020 16:08:16 -0700 Message-Id: <20200731230820.1742553-33-keescook@chromium.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200731230820.1742553-1-keescook@chromium.org> References: <20200731230820.1742553-1-keescook@chromium.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org For readability, move the zero-sized sections to the end after DISCARDS and mark them NOLOAD for good measure. Signed-off-by: Kees Cook --- arch/x86/boot/compressed/vmlinux.lds.S | 42 +++++++++++++++----------- 1 file changed, 25 insertions(+), 17 deletions(-) diff --git a/arch/x86/boot/compressed/vmlinux.lds.S b/arch/x86/boot/compressed/vmlinux.lds.S index 3c2ee9a5bf43..42dea70a5091 100644 --- a/arch/x86/boot/compressed/vmlinux.lds.S +++ b/arch/x86/boot/compressed/vmlinux.lds.S @@ -42,18 +42,16 @@ SECTIONS *(.rodata.*) _erodata = . ; } - .rel.dyn : { - *(.rel.*) - } - .rela.dyn : { - *(.rela.*) - } - .got : { - *(.got) - } .got.plt : { *(.got.plt) } + ASSERT(SIZEOF(.got.plt) == 0 || +#ifdef CONFIG_X86_64 + SIZEOF(.got.plt) == 0x18, +#else + SIZEOF(.got.plt) == 0xc, +#endif + "Unexpected GOT/PLT entries detected!") .data : { _data = . ; @@ -85,13 +83,23 @@ SECTIONS ELF_DETAILS DISCARDS -} -ASSERT(SIZEOF(.got) == 0, "Unexpected GOT entries detected!") -#ifdef CONFIG_X86_64 -ASSERT(SIZEOF(.got.plt) == 0 || SIZEOF(.got.plt) == 0x18, "Unexpected GOT/PLT entries detected!") -#else -ASSERT(SIZEOF(.got.plt) == 0 || SIZEOF(.got.plt) == 0xc, "Unexpected GOT/PLT entries detected!") -#endif + /* + * Sections that should stay zero sized, which is safer to + * explicitly check instead of blindly discarding. + */ + .got (NOLOAD) : { + *(.got) + } + ASSERT(SIZEOF(.got) == 0, "Unexpected GOT entries detected!") -ASSERT(SIZEOF(.rel.dyn) == 0 && SIZEOF(.rela.dyn) == 0, "Unexpected run-time relocations detected!") + /* ld.lld does not like .rel* sections being made "NOLOAD". */ + .rel.dyn : { + *(.rel.*) + } + ASSERT(SIZEOF(.rel.dyn) == 0, "Unexpected run-time relocations (.rel) detected!") + .rela.dyn : { + *(.rela.*) + } + ASSERT(SIZEOF(.rela.dyn) == 0, "Unexpected run-time relocations (.rela) detected!") +} -- 2.25.1