From 2f40fdd6bc0e1beca522657d3c9242e7b25917a2 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 23 Jun 2016 15:59:42 -0700 Subject: [PATCH] BACKPORT: arm64/uaccess: Enable hardened usercopy Enables CONFIG_HARDENED_USERCOPY checks on arm64. As done by KASAN in -next, renames the low-level functions to __arch_copy_*_user() so a static inline can do additional work before the copy. Signed-off-by: Kees Cook Change-Id: I1286cae8e6ffcf12ea54ddd62f1a6d2ce742c8d0 (cherry picked from commit faf5b63e294151d6ac24ca6906d6f221bd3496cd) Signed-off-by: Sami Tolvanen --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/uaccess.h | 29 ++++++++++++++++++++++------- arch/arm64/kernel/arm64ksyms.c | 4 ++-- arch/arm64/lib/copy_from_user.S | 4 ++-- arch/arm64/lib/copy_to_user.S | 4 ++-- 5 files changed, 29 insertions(+), 13 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 579ab688312d..3ad9d9ea374b 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -48,6 +48,7 @@ config ARM64 select HAVE_ALIGNED_STRUCT_PAGE if SLUB select HAVE_ARCH_AUDITSYSCALL select HAVE_ARCH_BITREVERSE + select HAVE_ARCH_HARDENED_USERCOPY select HAVE_ARCH_JUMP_LABEL select HAVE_ARCH_KASAN if SPARSEMEM_VMEMMAP && !(ARM64_16K_PAGES && ARM64_VA_BITS_48) select HAVE_ARCH_KGDB diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index b2ede967fe7d..2a44b9795532 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -247,24 +247,39 @@ do { \ -EFAULT; \ }) -extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n); -extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n); +extern unsigned long __must_check __arch_copy_from_user(void *to, const void __user *from, unsigned long n); +extern unsigned long __must_check __arch_copy_to_user(void __user *to, const void *from, unsigned long n); extern unsigned long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n); extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n); +static inline unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n) +{ + check_object_size(to, n, false); + return __arch_copy_from_user(to, from, n); +} + +static inline unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n) +{ + check_object_size(from, n, true); + return __arch_copy_to_user(to, from, n); +} + static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n) { - if (access_ok(VERIFY_READ, from, n)) - n = __copy_from_user(to, from, n); - else /* security hole - plug it */ + if (access_ok(VERIFY_READ, from, n)) { + check_object_size(to, n, false); + n = __arch_copy_from_user(to, from, n); + } else /* security hole - plug it */ memset(to, 0, n); return n; } static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n) { - if (access_ok(VERIFY_WRITE, to, n)) - n = __copy_to_user(to, from, n); + if (access_ok(VERIFY_WRITE, to, n)) { + check_object_size(from, n, true); + n = __arch_copy_to_user(to, from, n); + } return n; } diff --git a/arch/arm64/kernel/arm64ksyms.c b/arch/arm64/kernel/arm64ksyms.c index 3b6d8cc9dfe0..c654df05b7d7 100644 --- a/arch/arm64/kernel/arm64ksyms.c +++ b/arch/arm64/kernel/arm64ksyms.c @@ -33,8 +33,8 @@ EXPORT_SYMBOL(copy_page); EXPORT_SYMBOL(clear_page); /* user mem (segment) */ -EXPORT_SYMBOL(__copy_from_user); -EXPORT_SYMBOL(__copy_to_user); +EXPORT_SYMBOL(__arch_copy_from_user); +EXPORT_SYMBOL(__arch_copy_to_user); EXPORT_SYMBOL(__clear_user); EXPORT_SYMBOL(__copy_in_user); diff --git a/arch/arm64/lib/copy_from_user.S b/arch/arm64/lib/copy_from_user.S index 4699cd74f87e..281e75db899a 100644 --- a/arch/arm64/lib/copy_from_user.S +++ b/arch/arm64/lib/copy_from_user.S @@ -66,7 +66,7 @@ .endm end .req x5 -ENTRY(__copy_from_user) +ENTRY(__arch_copy_from_user) ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(0)), ARM64_HAS_PAN, \ CONFIG_ARM64_PAN) add end, x0, x2 @@ -75,7 +75,7 @@ ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(1)), ARM64_HAS_PAN, \ CONFIG_ARM64_PAN) mov x0, #0 // Nothing to copy ret -ENDPROC(__copy_from_user) +ENDPROC(__arch_copy_from_user) .section .fixup,"ax" .align 2 diff --git a/arch/arm64/lib/copy_to_user.S b/arch/arm64/lib/copy_to_user.S index 7512bbbc07ac..db4d187de61f 100644 --- a/arch/arm64/lib/copy_to_user.S +++ b/arch/arm64/lib/copy_to_user.S @@ -65,7 +65,7 @@ .endm end .req x5 -ENTRY(__copy_to_user) +ENTRY(__arch_copy_to_user) ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(0)), ARM64_HAS_PAN, \ CONFIG_ARM64_PAN) add end, x0, x2 @@ -74,7 +74,7 @@ ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(1)), ARM64_HAS_PAN, \ CONFIG_ARM64_PAN) mov x0, #0 ret -ENDPROC(__copy_to_user) +ENDPROC(__arch_copy_to_user) .section .fixup,"ax" .align 2 -- 2.20.1