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>, 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 v2 02/17] cfi: add __cficanonical Date: Thu, 18 Mar 2021 10:10:56 -0700 [thread overview] Message-ID: <20210318171111.706303-3-samitolvanen@google.com> (raw) In-Reply-To: <20210318171111.706303-1-samitolvanen@google.com> With CONFIG_CFI_CLANG, the compiler replaces a function address taken in C code with the address of a local jump table entry, which passes runtime indirect call checks. However, the compiler won't replace addresses taken in assembly code, which will result in a CFI failure if we later jump to such an address in instrumented C code. The code generated for the non-canonical jump table looks this: <noncanonical.cfi_jt>: /* In C, &noncanonical points here */ jmp noncanonical ... <noncanonical>: /* function body */ ... This change adds the __cficanonical attribute, which tells the compiler to use a canonical jump table for the function instead. This means the compiler will rename the actual function to <function>.cfi and points the original symbol to the jump table entry instead: <canonical>: /* jump table entry */ jmp canonical.cfi ... <canonical.cfi>: /* function body */ ... As a result, the address taken in assembly, or other non-instrumented code always points to the jump table and therefore, can be used for indirect calls in instrumented code without tripping CFI checks. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Bjorn Helgaas <bhelgaas@google.com> # pci.h --- include/linux/compiler-clang.h | 1 + include/linux/compiler_types.h | 4 ++++ include/linux/init.h | 4 ++-- include/linux/pci.h | 4 ++-- 4 files changed, 9 insertions(+), 4 deletions(-) diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h index 6de9d0c9377e..adbe76b203e2 100644 --- a/include/linux/compiler-clang.h +++ b/include/linux/compiler-clang.h @@ -63,3 +63,4 @@ #endif #define __nocfi __attribute__((__no_sanitize__("cfi"))) +#define __cficanonical __attribute__((__cfi_canonical_jump_table__)) diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index 796935a37e37..d29bda7f6ebd 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -246,6 +246,10 @@ struct ftrace_likely_data { # define __nocfi #endif +#ifndef __cficanonical +# define __cficanonical +#endif + #ifndef asm_volatile_goto #define asm_volatile_goto(x...) asm goto(x) #endif diff --git a/include/linux/init.h b/include/linux/init.h index b3ea15348fbd..045ad1650ed1 100644 --- a/include/linux/init.h +++ b/include/linux/init.h @@ -220,8 +220,8 @@ extern bool initcall_debug; __initcall_name(initstub, __iid, id) #define __define_initcall_stub(__stub, fn) \ - int __init __stub(void); \ - int __init __stub(void) \ + int __init __cficanonical __stub(void); \ + int __init __cficanonical __stub(void) \ { \ return fn(); \ } \ diff --git a/include/linux/pci.h b/include/linux/pci.h index 86c799c97b77..39684b72db91 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1944,8 +1944,8 @@ enum pci_fixup_pass { #ifdef CONFIG_LTO_CLANG #define __DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class, \ class_shift, hook, stub) \ - void stub(struct pci_dev *dev); \ - void stub(struct pci_dev *dev) \ + void __cficanonical stub(struct pci_dev *dev); \ + void __cficanonical stub(struct pci_dev *dev) \ { \ hook(dev); \ } \ -- 2.31.0.291.g576ba9dcdaf-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>, 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 v2 02/17] cfi: add __cficanonical Date: Thu, 18 Mar 2021 10:10:56 -0700 [thread overview] Message-ID: <20210318171111.706303-3-samitolvanen@google.com> (raw) In-Reply-To: <20210318171111.706303-1-samitolvanen@google.com> With CONFIG_CFI_CLANG, the compiler replaces a function address taken in C code with the address of a local jump table entry, which passes runtime indirect call checks. However, the compiler won't replace addresses taken in assembly code, which will result in a CFI failure if we later jump to such an address in instrumented C code. The code generated for the non-canonical jump table looks this: <noncanonical.cfi_jt>: /* In C, &noncanonical points here */ jmp noncanonical ... <noncanonical>: /* function body */ ... This change adds the __cficanonical attribute, which tells the compiler to use a canonical jump table for the function instead. This means the compiler will rename the actual function to <function>.cfi and points the original symbol to the jump table entry instead: <canonical>: /* jump table entry */ jmp canonical.cfi ... <canonical.cfi>: /* function body */ ... As a result, the address taken in assembly, or other non-instrumented code always points to the jump table and therefore, can be used for indirect calls in instrumented code without tripping CFI checks. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Bjorn Helgaas <bhelgaas@google.com> # pci.h --- include/linux/compiler-clang.h | 1 + include/linux/compiler_types.h | 4 ++++ include/linux/init.h | 4 ++-- include/linux/pci.h | 4 ++-- 4 files changed, 9 insertions(+), 4 deletions(-) diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h index 6de9d0c9377e..adbe76b203e2 100644 --- a/include/linux/compiler-clang.h +++ b/include/linux/compiler-clang.h @@ -63,3 +63,4 @@ #endif #define __nocfi __attribute__((__no_sanitize__("cfi"))) +#define __cficanonical __attribute__((__cfi_canonical_jump_table__)) diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index 796935a37e37..d29bda7f6ebd 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -246,6 +246,10 @@ struct ftrace_likely_data { # define __nocfi #endif +#ifndef __cficanonical +# define __cficanonical +#endif + #ifndef asm_volatile_goto #define asm_volatile_goto(x...) asm goto(x) #endif diff --git a/include/linux/init.h b/include/linux/init.h index b3ea15348fbd..045ad1650ed1 100644 --- a/include/linux/init.h +++ b/include/linux/init.h @@ -220,8 +220,8 @@ extern bool initcall_debug; __initcall_name(initstub, __iid, id) #define __define_initcall_stub(__stub, fn) \ - int __init __stub(void); \ - int __init __stub(void) \ + int __init __cficanonical __stub(void); \ + int __init __cficanonical __stub(void) \ { \ return fn(); \ } \ diff --git a/include/linux/pci.h b/include/linux/pci.h index 86c799c97b77..39684b72db91 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1944,8 +1944,8 @@ enum pci_fixup_pass { #ifdef CONFIG_LTO_CLANG #define __DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class, \ class_shift, hook, stub) \ - void stub(struct pci_dev *dev); \ - void stub(struct pci_dev *dev) \ + void __cficanonical stub(struct pci_dev *dev); \ + void __cficanonical stub(struct pci_dev *dev) \ { \ hook(dev); \ } \ -- 2.31.0.291.g576ba9dcdaf-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:[~2021-03-18 17:12 UTC|newest] Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-03-18 17:10 [PATCH v2 00/17] Add support for Clang CFI Sami Tolvanen 2021-03-18 17:10 ` Sami Tolvanen 2021-03-18 17:10 ` [PATCH v2 01/17] add " Sami Tolvanen 2021-03-18 17:10 ` Sami Tolvanen 2021-03-18 22:29 ` Peter Zijlstra 2021-03-18 22:29 ` Peter Zijlstra 2021-03-18 23:48 ` Sami Tolvanen 2021-03-18 23:48 ` Sami Tolvanen 2021-03-19 12:26 ` Peter Zijlstra 2021-03-19 12:26 ` Peter Zijlstra 2021-03-19 13:52 ` Paul E. McKenney 2021-03-19 13:52 ` Paul E. McKenney 2021-03-19 16:17 ` Sami Tolvanen 2021-03-19 16:17 ` Sami Tolvanen 2021-03-19 17:03 ` Paul E. McKenney 2021-03-19 17:03 ` Paul E. McKenney 2021-03-18 17:10 ` Sami Tolvanen [this message] 2021-03-18 17:10 ` [PATCH v2 02/17] cfi: add __cficanonical Sami Tolvanen 2021-03-18 17:49 ` Nick Desaulniers 2021-03-18 17:49 ` Nick Desaulniers 2021-03-18 17:10 ` [PATCH v2 03/17] mm: add generic __va_function and __pa_function macros Sami Tolvanen 2021-03-18 17:10 ` Sami Tolvanen 2021-03-18 17:10 ` [PATCH v2 04/17] module: ensure __cfi_check alignment Sami Tolvanen 2021-03-18 17:10 ` Sami Tolvanen 2021-03-18 19:27 ` Nick Desaulniers 2021-03-18 19:27 ` Nick Desaulniers 2021-03-18 21:43 ` Sami Tolvanen 2021-03-18 21:43 ` Sami Tolvanen 2021-03-18 17:10 ` [PATCH v2 05/17] workqueue: use WARN_ON_FUNCTION_MISMATCH Sami Tolvanen 2021-03-18 17:10 ` Sami Tolvanen 2021-03-18 18:50 ` Nick Desaulniers 2021-03-18 18:50 ` Nick Desaulniers 2021-03-18 21:38 ` Sami Tolvanen 2021-03-18 21:38 ` Sami Tolvanen 2021-03-18 17:11 ` [PATCH v2 06/17] kthread: " Sami Tolvanen 2021-03-18 17:11 ` Sami Tolvanen 2021-03-18 17:11 ` [PATCH v2 07/17] kallsyms: strip ThinLTO hashes from static functions Sami Tolvanen 2021-03-18 17:11 ` Sami Tolvanen 2021-03-18 19:00 ` Nick Desaulniers 2021-03-18 19:00 ` Nick Desaulniers 2021-03-18 21:41 ` Sami Tolvanen 2021-03-18 21:41 ` Sami Tolvanen 2021-03-18 17:11 ` [PATCH v2 08/17] bpf: disable CFI in dispatcher functions Sami Tolvanen 2021-03-18 17:11 ` Sami Tolvanen 2021-03-18 17:11 ` [PATCH v2 09/17] lib/list_sort: fix function type mismatches Sami Tolvanen 2021-03-18 17:11 ` Sami Tolvanen 2021-03-18 18:31 ` Nick Desaulniers 2021-03-18 18:31 ` Nick Desaulniers 2021-03-18 21:31 ` Sami Tolvanen 2021-03-18 21:31 ` Sami Tolvanen 2021-03-18 17:11 ` [PATCH v2 10/17] lkdtm: use __va_function Sami Tolvanen 2021-03-18 17:11 ` Sami Tolvanen 2021-03-18 18:43 ` Nick Desaulniers 2021-03-18 18:43 ` Nick Desaulniers 2021-03-18 18:45 ` Nick Desaulniers 2021-03-18 18:45 ` Nick Desaulniers 2021-03-18 17:11 ` [PATCH v2 11/17] psci: use __pa_function for cpu_resume Sami Tolvanen 2021-03-18 17:11 ` Sami Tolvanen 2021-03-18 17:11 ` [PATCH v2 12/17] arm64: implement __va_function Sami Tolvanen 2021-03-18 17:11 ` Sami Tolvanen 2021-03-18 17:11 ` [PATCH v2 13/17] arm64: use __pa_function Sami Tolvanen 2021-03-18 17:11 ` Sami Tolvanen 2021-03-18 17:11 ` [PATCH v2 14/17] arm64: add __nocfi to functions that jump to a physical address Sami Tolvanen 2021-03-18 17:11 ` Sami Tolvanen 2021-03-18 17:11 ` [PATCH v2 15/17] arm64: add __nocfi to __apply_alternatives Sami Tolvanen 2021-03-18 17:11 ` Sami Tolvanen 2021-03-18 17:11 ` [PATCH v2 16/17] KVM: arm64: Disable CFI for nVHE Sami Tolvanen 2021-03-18 17:11 ` Sami Tolvanen 2021-03-18 17:11 ` [PATCH v2 17/17] arm64: allow CONFIG_CFI_CLANG to be selected Sami Tolvanen 2021-03-18 17:11 ` Sami Tolvanen
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20210318171111.706303-3-samitolvanen@google.com \ --to=samitolvanen@google.com \ --cc=arnd@arndb.de \ --cc=bpf@vger.kernel.org \ --cc=hch@infradead.org \ --cc=jeyu@kernel.org \ --cc=keescook@chromium.org \ --cc=linux-arch@vger.kernel.org \ --cc=linux-arm-kernel@lists.infradead.org \ --cc=linux-hardening@vger.kernel.org \ --cc=linux-kbuild@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-pci@vger.kernel.org \ --cc=masahiroy@kernel.org \ --cc=nathan@kernel.org \ --cc=ndesaulniers@google.com \ --cc=paulmck@kernel.org \ --cc=tj@kernel.org \ --cc=will@kernel.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.