From 08626a6056aad824c43d34ce587ab2b01f49d1a4 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 16 Aug 2017 14:09:13 -0700 Subject: arm: Implement thread_struct whitelist for hardened usercopy While ARM32 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: Russell King Cc: Ingo Molnar Cc: Christian Borntraeger Cc: "Peter Zijlstra (Intel)" Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Kees Cook --- arch/arm/Kconfig | 1 + arch/arm/include/asm/processor.h | 10 ++++++++++ 2 files changed, 11 insertions(+) (limited to 'arch') diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 51c8df561077..3ea00d65f35d 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -50,6 +50,7 @@ config ARM select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU select HAVE_ARCH_MMAP_RND_BITS if MMU select HAVE_ARCH_SECCOMP_FILTER if (AEABI && !OABI_COMPAT) + select HAVE_ARCH_THREAD_STRUCT_WHITELIST select HAVE_ARCH_TRACEHOOK select HAVE_ARM_SMCCC if CPU_V7 select HAVE_EBPF_JIT if !CPU_ENDIAN_BE32 diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h index 338cbe0a18ef..1bf65b47808a 100644 --- a/arch/arm/include/asm/processor.h +++ b/arch/arm/include/asm/processor.h @@ -45,6 +45,16 @@ struct thread_struct { struct debug_info debug; }; +/* + * 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; +} + #define INIT_THREAD { } #define start_thread(regs,pc,sp) \ -- cgit