[PATCH 5/6] powerpc: Use barrier_nospec in copy_from_user()
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2018-04-24 04:16:20
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
Based on the x86 commit doing the same.
See commit 304ec1b05031 ("x86/uaccess: Use __uaccess_begin_nospec()
and uaccess_try_nospec") and b3bbfb3fb5d2 ("x86: Introduce
__uaccess_begin_nospec() and uaccess_try_nospec") for more detail.
In all cases we are ordering the load from the potentially
user-controlled pointer vs a previous branch based on an access_ok()
check or similar.
Base on a patch from Michal Suchanek.
Signed-off-by: Michal Suchanek <redacted>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
arch/powerpc/include/asm/uaccess.h | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index a62ee663b2c8..6dc3d2eeea4a 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h@@ -252,6 +252,7 @@ do { \ __chk_user_ptr(ptr); \ if (!is_kernel_addr((unsigned long)__gu_addr)) \ might_fault(); \ + barrier_nospec(); \ __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \ (x) = (__typeof__(*(ptr)))__gu_val; \ __gu_err; \
@@ -263,8 +264,10 @@ do { \ unsigned long __gu_val = 0; \ const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \ might_fault(); \ - if (access_ok(VERIFY_READ, __gu_addr, (size))) \ + if (access_ok(VERIFY_READ, __gu_addr, (size))) { \ + barrier_nospec(); \ __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \ + } \ (x) = (__force __typeof__(*(ptr)))__gu_val; \ __gu_err; \ })
@@ -275,6 +278,7 @@ do { \ unsigned long __gu_val; \ const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \ __chk_user_ptr(ptr); \ + barrier_nospec(); \ __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \ (x) = (__force __typeof__(*(ptr)))__gu_val; \ __gu_err; \
@@ -302,15 +306,19 @@ static inline unsigned long raw_copy_from_user(void *to, switch (n) { case 1: + barrier_nospec(); __get_user_size(*(u8 *)to, from, 1, ret); break; case 2: + barrier_nospec(); __get_user_size(*(u16 *)to, from, 2, ret); break; case 4: + barrier_nospec(); __get_user_size(*(u32 *)to, from, 4, ret); break; case 8: + barrier_nospec(); __get_user_size(*(u64 *)to, from, 8, ret); break; }
@@ -318,6 +326,7 @@ static inline unsigned long raw_copy_from_user(void *to, return 0; } + barrier_nospec(); return __copy_tofrom_user((__force void __user *)to, from, n); }
--
2.14.1