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Subject[PATCH 6/9] powerpc/uaccess: Enable hardened usercopy
Date
Enables CONFIG_HARDENED_USERCOPY checks on powerpc.

Based on code from PaX and grsecurity.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/uaccess.h | 21 +++++++++++++++++++--
2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 01f7464d9fea..b7a18b2604be 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -164,6 +164,7 @@ config PPC
select ARCH_HAS_UBSAN_SANITIZE_ALL
select ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
select HAVE_LIVEPATCH if HAVE_DYNAMIC_FTRACE_WITH_REGS
+ select HAVE_ARCH_HARDENED_USERCOPY

config GENERIC_CSUM
def_bool CPU_LITTLE_ENDIAN
diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index b7c20f0b8fbe..c1dc6c14deb8 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -310,10 +310,15 @@ static inline unsigned long copy_from_user(void *to,
{
unsigned long over;

- if (access_ok(VERIFY_READ, from, n))
+ if (access_ok(VERIFY_READ, from, n)) {
+ if (!__builtin_constant_p(n))
+ check_object_size(to, n, false);
return __copy_tofrom_user((__force void __user *)to, from, n);
+ }
if ((unsigned long)from < TASK_SIZE) {
over = (unsigned long)from + n - TASK_SIZE;
+ if (!__builtin_constant_p(n - over))
+ check_object_size(to, n - over, false);
return __copy_tofrom_user((__force void __user *)to, from,
n - over) + over;
}
@@ -325,10 +330,15 @@ static inline unsigned long copy_to_user(void __user *to,
{
unsigned long over;

- if (access_ok(VERIFY_WRITE, to, n))
+ if (access_ok(VERIFY_WRITE, to, n)) {
+ if (!__builtin_constant_p(n))
+ check_object_size(from, n, true);
return __copy_tofrom_user(to, (__force void __user *)from, n);
+ }
if ((unsigned long)to < TASK_SIZE) {
over = (unsigned long)to + n - TASK_SIZE;
+ if (!__builtin_constant_p(n))
+ check_object_size(from, n - over, true);
return __copy_tofrom_user(to, (__force void __user *)from,
n - over) + over;
}
@@ -372,6 +382,10 @@ static inline unsigned long __copy_from_user_inatomic(void *to,
if (ret == 0)
return 0;
}
+
+ if (!__builtin_constant_p(n))
+ check_object_size(to, n, false);
+
return __copy_tofrom_user((__force void __user *)to, from, n);
}

@@ -398,6 +412,9 @@ static inline unsigned long __copy_to_user_inatomic(void __user *to,
if (ret == 0)
return 0;
}
+ if (!__builtin_constant_p(n))
+ check_object_size(from, n, true);
+
return __copy_tofrom_user(to, (__force const void __user *)from, n);
}

--
2.7.4
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