From 9e8084d3f761413b2d58b2625bc6e332eab2bfce Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 16 Aug 2017 14:05:09 -0700 Subject: [PATCH] arm64: Implement thread_struct whitelist for hardened usercopy While ARM64 carries FPU state in the thread structure that is saved and restored during signal handling, it doesn't need to declare a usercopy whitelist, since existing accessors are all either using a bounce buffer (for which whitelisting isn't checking the slab), are statically sized (which will bypass the hardened usercopy check), or both. Cc: Catalin Marinas Cc: Will Deacon Cc: Christian Borntraeger Cc: Ingo Molnar Cc: James Morse Cc: "Peter Zijlstra (Intel)" Cc: Dave Martin Cc: zijun_hu Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Kees Cook --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/processor.h | 10 ++++++++++ 2 files changed, 11 insertions(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index a93339f5178f..c84477e6a884 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -90,6 +90,7 @@ config ARM64 select HAVE_ARCH_MMAP_RND_BITS select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT select HAVE_ARCH_SECCOMP_FILTER + select HAVE_ARCH_THREAD_STRUCT_WHITELIST select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE select HAVE_ARCH_VMAP_STACK diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index 023cacb946c3..ba6c9ce6cc75 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -113,6 +113,16 @@ struct thread_struct { struct debug_info debug; /* debugging */ }; +/* + * Everything usercopied to/from thread_struct is statically-sized, so + * no hardened usercopy whitelist is needed. + */ +static inline void arch_thread_struct_whitelist(unsigned long *offset, + unsigned long *size) +{ + *offset = *size = 0; +} + #ifdef CONFIG_COMPAT #define task_user_tls(t) \ ({ \