From: Sami Tolvanen <samitolvanen@google.com> To: Kees Cook <keescook@chromium.org> Cc: Nathan Chancellor <nathan@kernel.org>, Nick Desaulniers <ndesaulniers@google.com>, Masahiro Yamada <masahiroy@kernel.org>, Will Deacon <will@kernel.org>, Jessica Yu <jeyu@kernel.org>, Arnd Bergmann <arnd@arndb.de>, Tejun Heo <tj@kernel.org>, "Paul E. McKenney" <paulmck@kernel.org>, Christoph Hellwig <hch@infradead.org>, Peter Zijlstra <peterz@infradead.org>, Sedat Dilek <sedat.dilek@gmail.com>, Mark Rutland <mark.rutland@arm.com>, Catalin Marinas <catalin.marinas@arm.com>, bpf@vger.kernel.org, linux-hardening@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Sami Tolvanen <samitolvanen@google.com> Subject: [PATCH v5 04/18] module: ensure __cfi_check alignment Date: Thu, 1 Apr 2021 16:32:02 -0700 [thread overview] Message-ID: <20210401233216.2540591-5-samitolvanen@google.com> (raw) In-Reply-To: <20210401233216.2540591-1-samitolvanen@google.com> CONFIG_CFI_CLANG_SHADOW assumes the __cfi_check() function is page aligned and at the beginning of the .text section. While Clang would normally align the function correctly, it fails to do so for modules with no executable code. This change ensures the correct __cfi_check() location and alignment. It also discards the .eh_frame section, which Clang can generate with certain sanitizers, such as CFI. Link: https://bugs.llvm.org/show_bug.cgi?id=46293 Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Jessica Yu <jeyu@kernel.org> --- scripts/module.lds.S | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/scripts/module.lds.S b/scripts/module.lds.S index 168cd27e6122..f8022b34e388 100644 --- a/scripts/module.lds.S +++ b/scripts/module.lds.S @@ -3,10 +3,20 @@ * Archs are free to supply their own linker scripts. ld will * combine them automatically. */ +#ifdef CONFIG_CFI_CLANG +# include <asm/page.h> +# define ALIGN_CFI ALIGN(PAGE_SIZE) +# define SANITIZER_DISCARDS *(.eh_frame) +#else +# define ALIGN_CFI +# define SANITIZER_DISCARDS +#endif + SECTIONS { /DISCARD/ : { *(.discard) *(.discard.*) + SANITIZER_DISCARDS } __ksymtab 0 : { *(SORT(___ksymtab+*)) } @@ -40,7 +50,14 @@ SECTIONS { *(.rodata..L*) } - .text : { *(.text .text.[0-9a-zA-Z_]*) } + /* + * With CONFIG_CFI_CLANG, we assume __cfi_check is at the beginning + * of the .text section, and is aligned to PAGE_SIZE. + */ + .text : ALIGN_CFI { + *(.text.__cfi_check) + *(.text .text.[0-9a-zA-Z_]* .text..L.cfi*) + } } /* bring in arch-specific sections */ -- 2.31.0.208.g409f899ff0-goog
WARNING: multiple messages have this Message-ID (diff)
From: Sami Tolvanen <samitolvanen@google.com> To: Kees Cook <keescook@chromium.org> Cc: Nathan Chancellor <nathan@kernel.org>, Nick Desaulniers <ndesaulniers@google.com>, Masahiro Yamada <masahiroy@kernel.org>, Will Deacon <will@kernel.org>, Jessica Yu <jeyu@kernel.org>, Arnd Bergmann <arnd@arndb.de>, Tejun Heo <tj@kernel.org>, "Paul E. McKenney" <paulmck@kernel.org>, Christoph Hellwig <hch@infradead.org>, Peter Zijlstra <peterz@infradead.org>, Sedat Dilek <sedat.dilek@gmail.com>, Mark Rutland <mark.rutland@arm.com>, Catalin Marinas <catalin.marinas@arm.com>, bpf@vger.kernel.org, linux-hardening@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Sami Tolvanen <samitolvanen@google.com> Subject: [PATCH v5 04/18] module: ensure __cfi_check alignment Date: Thu, 1 Apr 2021 16:32:02 -0700 [thread overview] Message-ID: <20210401233216.2540591-5-samitolvanen@google.com> (raw) In-Reply-To: <20210401233216.2540591-1-samitolvanen@google.com> CONFIG_CFI_CLANG_SHADOW assumes the __cfi_check() function is page aligned and at the beginning of the .text section. While Clang would normally align the function correctly, it fails to do so for modules with no executable code. This change ensures the correct __cfi_check() location and alignment. It also discards the .eh_frame section, which Clang can generate with certain sanitizers, such as CFI. Link: https://bugs.llvm.org/show_bug.cgi?id=46293 Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Jessica Yu <jeyu@kernel.org> --- scripts/module.lds.S | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/scripts/module.lds.S b/scripts/module.lds.S index 168cd27e6122..f8022b34e388 100644 --- a/scripts/module.lds.S +++ b/scripts/module.lds.S @@ -3,10 +3,20 @@ * Archs are free to supply their own linker scripts. ld will * combine them automatically. */ +#ifdef CONFIG_CFI_CLANG +# include <asm/page.h> +# define ALIGN_CFI ALIGN(PAGE_SIZE) +# define SANITIZER_DISCARDS *(.eh_frame) +#else +# define ALIGN_CFI +# define SANITIZER_DISCARDS +#endif + SECTIONS { /DISCARD/ : { *(.discard) *(.discard.*) + SANITIZER_DISCARDS } __ksymtab 0 : { *(SORT(___ksymtab+*)) } @@ -40,7 +50,14 @@ SECTIONS { *(.rodata..L*) } - .text : { *(.text .text.[0-9a-zA-Z_]*) } + /* + * With CONFIG_CFI_CLANG, we assume __cfi_check is at the beginning + * of the .text section, and is aligned to PAGE_SIZE. + */ + .text : ALIGN_CFI { + *(.text.__cfi_check) + *(.text .text.[0-9a-zA-Z_]* .text..L.cfi*) + } } /* bring in arch-specific sections */ -- 2.31.0.208.g409f899ff0-goog _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-04-01 23:32 UTC|newest] Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-04-01 23:31 [PATCH v5 00/18] Add support for Clang CFI Sami Tolvanen 2021-04-01 23:31 ` Sami Tolvanen 2021-04-01 23:31 ` [PATCH v5 01/18] add " Sami Tolvanen 2021-04-01 23:31 ` Sami Tolvanen 2021-04-01 23:32 ` [PATCH v5 02/18] cfi: add __cficanonical Sami Tolvanen 2021-04-01 23:32 ` Sami Tolvanen 2021-04-01 23:32 ` [PATCH v5 03/18] mm: add generic function_nocfi macro Sami Tolvanen 2021-04-01 23:32 ` Sami Tolvanen 2021-04-02 6:37 ` Christoph Hellwig 2021-04-02 6:37 ` Christoph Hellwig 2021-04-06 11:27 ` Mark Rutland 2021-04-06 11:27 ` Mark Rutland 2021-04-01 23:32 ` Sami Tolvanen [this message] 2021-04-01 23:32 ` [PATCH v5 04/18] module: ensure __cfi_check alignment Sami Tolvanen 2021-04-01 23:32 ` [PATCH v5 05/18] workqueue: use WARN_ON_FUNCTION_MISMATCH Sami Tolvanen 2021-04-01 23:32 ` Sami Tolvanen 2021-04-01 23:32 ` [PATCH v5 06/18] kthread: " Sami Tolvanen 2021-04-01 23:32 ` Sami Tolvanen 2021-04-01 23:32 ` [PATCH v5 07/18] kallsyms: strip ThinLTO hashes from static functions Sami Tolvanen 2021-04-01 23:32 ` Sami Tolvanen 2021-04-01 23:32 ` [PATCH v5 08/18] bpf: disable CFI in dispatcher functions Sami Tolvanen 2021-04-01 23:32 ` Sami Tolvanen 2021-04-01 23:32 ` [PATCH v5 09/18] treewide: Change list_sort to use const pointers Sami Tolvanen 2021-04-01 23:32 ` Sami Tolvanen 2021-04-01 23:32 ` [PATCH v5 10/18] lkdtm: use function_nocfi Sami Tolvanen 2021-04-01 23:32 ` Sami Tolvanen 2021-04-01 23:32 ` [PATCH v5 11/18] psci: use function_nocfi for cpu_resume Sami Tolvanen 2021-04-01 23:32 ` Sami Tolvanen 2021-04-06 11:27 ` Mark Rutland 2021-04-06 11:27 ` Mark Rutland 2021-04-01 23:32 ` [PATCH v5 12/18] arm64: implement function_nocfi Sami Tolvanen 2021-04-01 23:32 ` Sami Tolvanen 2021-04-06 11:36 ` Mark Rutland 2021-04-06 11:36 ` Mark Rutland 2021-04-06 17:02 ` Sami Tolvanen 2021-04-06 17:02 ` Sami Tolvanen 2021-04-01 23:32 ` [PATCH v5 13/18] arm64: use function_nocfi with __pa_symbol Sami Tolvanen 2021-04-01 23:32 ` Sami Tolvanen 2021-04-06 11:41 ` Mark Rutland 2021-04-06 11:41 ` Mark Rutland 2021-04-01 23:32 ` [PATCH v5 14/18] arm64: add __nocfi to functions that jump to a physical address Sami Tolvanen 2021-04-01 23:32 ` Sami Tolvanen 2021-04-06 11:53 ` Mark Rutland 2021-04-06 11:53 ` Mark Rutland 2021-04-06 12:59 ` Ard Biesheuvel 2021-04-06 12:59 ` Ard Biesheuvel 2021-04-06 17:43 ` Sami Tolvanen 2021-04-06 17:43 ` Sami Tolvanen 2021-04-01 23:32 ` [PATCH v5 15/18] arm64: add __nocfi to __apply_alternatives Sami Tolvanen 2021-04-01 23:32 ` Sami Tolvanen 2021-04-01 23:32 ` [PATCH v5 16/18] arm64: ftrace: use function_nocfi for ftrace_call Sami Tolvanen 2021-04-01 23:32 ` Sami Tolvanen 2021-04-06 11:58 ` Mark Rutland 2021-04-06 11:58 ` Mark Rutland 2021-04-01 23:32 ` [PATCH v5 17/18] KVM: arm64: Disable CFI for nVHE Sami Tolvanen 2021-04-01 23:32 ` Sami Tolvanen 2021-04-01 23:32 ` [PATCH v5 18/18] arm64: allow CONFIG_CFI_CLANG to be selected Sami Tolvanen 2021-04-01 23:32 ` Sami Tolvanen 2021-04-02 19:58 ` [PATCH v5 00/18] Add support for Clang CFI Nathan Chancellor 2021-04-02 19:58 ` Nathan Chancellor
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