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>, 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, Sami Tolvanen <samitolvanen@google.com> Subject: [PATCH 03/17] mm: add generic __va_function and __pa_function macros Date: Thu, 11 Mar 2021 16:49:05 -0800 [thread overview] Message-ID: <20210312004919.669614-4-samitolvanen@google.com> (raw) In-Reply-To: <20210312004919.669614-1-samitolvanen@google.com> With CONFIG_CFI_CLANG, the compiler replaces function addresses in instrumented C code with jump table addresses. This means that __pa_symbol(function) returns the physical address of the jump table entry instead of the actual function, which may not work as the jump table code will immediately jump to a virtual address that may not be mapped. To avoid this address space confusion, this change adds generic definitions for __va_function and __pa_function, which architectures that support CFI can override. The typical implementation of the __va_function macro would use inline assembly to take the function address, which avoids compiler instrumentation. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> --- include/linux/mm.h | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 77e64e3eac80..1262c4c0242c 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -116,6 +116,14 @@ extern int mmap_rnd_compat_bits __read_mostly; #define __pa_symbol(x) __pa(RELOC_HIDE((unsigned long)(x), 0)) #endif +#ifndef __va_function +#define __va_function(x) (x) +#endif + +#ifndef __pa_function +#define __pa_function(x) __pa_symbol(__va_function(x)) +#endif + #ifndef page_to_virt #define page_to_virt(x) __va(PFN_PHYS(page_to_pfn(x))) #endif -- 2.31.0.rc2.261.g7f71774620-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>, 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, Sami Tolvanen <samitolvanen@google.com> Subject: [PATCH 03/17] mm: add generic __va_function and __pa_function macros Date: Thu, 11 Mar 2021 16:49:05 -0800 [thread overview] Message-ID: <20210312004919.669614-4-samitolvanen@google.com> (raw) In-Reply-To: <20210312004919.669614-1-samitolvanen@google.com> With CONFIG_CFI_CLANG, the compiler replaces function addresses in instrumented C code with jump table addresses. This means that __pa_symbol(function) returns the physical address of the jump table entry instead of the actual function, which may not work as the jump table code will immediately jump to a virtual address that may not be mapped. To avoid this address space confusion, this change adds generic definitions for __va_function and __pa_function, which architectures that support CFI can override. The typical implementation of the __va_function macro would use inline assembly to take the function address, which avoids compiler instrumentation. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> --- include/linux/mm.h | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 77e64e3eac80..1262c4c0242c 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -116,6 +116,14 @@ extern int mmap_rnd_compat_bits __read_mostly; #define __pa_symbol(x) __pa(RELOC_HIDE((unsigned long)(x), 0)) #endif +#ifndef __va_function +#define __va_function(x) (x) +#endif + +#ifndef __pa_function +#define __pa_function(x) __pa_symbol(__va_function(x)) +#endif + #ifndef page_to_virt #define page_to_virt(x) __va(PFN_PHYS(page_to_pfn(x))) #endif -- 2.31.0.rc2.261.g7f71774620-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:[~2021-03-12 0:50 UTC|newest] Thread overview: 84+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-03-12 0:49 [PATCH 00/17] Add support for Clang CFI Sami Tolvanen 2021-03-12 0:49 ` Sami Tolvanen 2021-03-12 0:49 ` [PATCH 01/17] add " Sami Tolvanen 2021-03-12 0:49 ` Sami Tolvanen 2021-03-12 2:39 ` Kees Cook 2021-03-12 2:39 ` Kees Cook 2021-03-12 0:49 ` [PATCH 02/17] cfi: add __cficanonical Sami Tolvanen 2021-03-12 0:49 ` Sami Tolvanen 2021-03-12 2:40 ` Kees Cook 2021-03-12 2:40 ` Kees Cook 2021-03-12 20:28 ` Bjorn Helgaas 2021-03-12 20:28 ` Bjorn Helgaas 2021-03-12 0:49 ` Sami Tolvanen [this message] 2021-03-12 0:49 ` [PATCH 03/17] mm: add generic __va_function and __pa_function macros Sami Tolvanen 2021-03-12 2:40 ` Kees Cook 2021-03-12 2:40 ` Kees Cook 2021-03-12 0:49 ` [PATCH 04/17] module: cfi: ensure __cfi_check alignment Sami Tolvanen 2021-03-12 0:49 ` Sami Tolvanen 2021-03-12 2:39 ` Kees Cook 2021-03-12 2:39 ` Kees Cook 2021-03-16 20:03 ` Sami Tolvanen 2021-03-16 20:03 ` Sami Tolvanen 2021-03-12 0:49 ` [PATCH 05/17] workqueue: cfi: disable callback pointer check with modules Sami Tolvanen 2021-03-12 0:49 ` Sami Tolvanen 2021-03-12 2:43 ` Kees Cook 2021-03-12 2:43 ` Kees Cook 2021-03-12 0:49 ` [PATCH 06/17] kthread: " Sami Tolvanen 2021-03-12 0:49 ` Sami Tolvanen 2021-03-12 2:43 ` Kees Cook 2021-03-12 2:43 ` Kees Cook 2021-03-12 6:13 ` Christoph Hellwig 2021-03-12 6:13 ` Christoph Hellwig 2021-03-17 16:05 ` Sami Tolvanen 2021-03-17 16:05 ` Sami Tolvanen 2021-03-12 0:49 ` [PATCH 07/17] kallsyms: cfi: strip hashes from static functions Sami Tolvanen 2021-03-12 0:49 ` Sami Tolvanen 2021-03-12 2:45 ` Kees Cook 2021-03-12 2:45 ` Kees Cook 2021-03-16 20:33 ` Sami Tolvanen 2021-03-16 20:33 ` Sami Tolvanen 2021-03-12 0:49 ` [PATCH 08/17] bpf: disable CFI in dispatcher functions Sami Tolvanen 2021-03-12 0:49 ` Sami Tolvanen 2021-03-12 2:45 ` Kees Cook 2021-03-12 2:45 ` Kees Cook 2021-03-12 0:49 ` [PATCH 09/17] lib/list_sort: fix function type mismatches Sami Tolvanen 2021-03-12 0:49 ` Sami Tolvanen 2021-03-12 2:45 ` Kees Cook 2021-03-12 2:45 ` Kees Cook 2021-03-12 0:49 ` [PATCH 10/17] lkdtm: use __va_function Sami Tolvanen 2021-03-12 0:49 ` Sami Tolvanen 2021-03-12 2:45 ` Kees Cook 2021-03-12 2:45 ` Kees Cook 2021-03-12 0:49 ` [PATCH 11/17] psci: use __pa_function for cpu_resume Sami Tolvanen 2021-03-12 0:49 ` Sami Tolvanen 2021-03-12 2:45 ` Kees Cook 2021-03-12 2:45 ` Kees Cook 2021-03-12 0:49 ` [PATCH 12/17] arm64: implement __va_function Sami Tolvanen 2021-03-12 0:49 ` Sami Tolvanen 2021-03-12 2:46 ` Kees Cook 2021-03-12 2:46 ` Kees Cook 2021-03-12 0:49 ` [PATCH 13/17] arm64: use __pa_function Sami Tolvanen 2021-03-12 0:49 ` Sami Tolvanen 2021-03-12 2:46 ` Kees Cook 2021-03-12 2:46 ` Kees Cook 2021-03-12 0:49 ` [PATCH 14/17] arm64: add __nocfi to functions that jump to a physical address Sami Tolvanen 2021-03-12 0:49 ` Sami Tolvanen 2021-03-12 2:47 ` Kees Cook 2021-03-12 2:47 ` Kees Cook 2021-03-12 0:49 ` [PATCH 15/17] arm64: add __nocfi to __apply_alternatives Sami Tolvanen 2021-03-12 0:49 ` Sami Tolvanen 2021-03-12 2:50 ` Kees Cook 2021-03-12 2:50 ` Kees Cook 2021-03-12 0:49 ` [PATCH 16/17] KVM: arm64: Disable CFI for nVHE Sami Tolvanen 2021-03-12 0:49 ` Sami Tolvanen 2021-03-12 2:50 ` Kees Cook 2021-03-12 2:50 ` Kees Cook 2021-03-12 0:49 ` [PATCH 17/17] arm64: allow CONFIG_CFI_CLANG to be selected Sami Tolvanen 2021-03-12 0:49 ` Sami Tolvanen 2021-03-12 2:51 ` Kees Cook 2021-03-12 2:51 ` Kees Cook 2021-03-16 20:44 ` Sami Tolvanen 2021-03-16 20:44 ` Sami Tolvanen 2021-03-16 23:02 ` Kees Cook 2021-03-16 23:02 ` Kees Cook
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