Add CONFIG_DEBUG_STRICT_USER_COPY_CHECKS, copied from the x86
implementation. Tested with 32 and 64bit kernel.
Signed-off-by: Helge Deller <deller@xxxxxx>
diff --git a/arch/parisc/Kconfig.debug b/arch/parisc/Kconfig.debug
index bc989e5..7305ac8 100644
--- a/arch/parisc/Kconfig.debug
+++ b/arch/parisc/Kconfig.debug
@@ -12,4 +12,18 @@ config DEBUG_RODATA
portion of the kernel code won't be covered by a TLB anymore.
If in doubt, say "N".
+config DEBUG_STRICT_USER_COPY_CHECKS
+ bool "Strict copy size checks"
+ depends on DEBUG_KERNEL && !TRACE_BRANCH_PROFILING
+ ---help---
+ Enabling this option turns a certain set of sanity checks for user
+ copy operations into compile time failures.
+
+ The copy_from_user() etc checks are there to help test if there
+ are sufficient security checks on the length argument of
+ the copy operation, by having gcc prove that the argument is
+ within bounds.
+
+ If unsure, or if you run an older (pre 4.4) gcc, say N.
+
endmenu
diff --git a/arch/parisc/include/asm/uaccess.h b/arch/parisc/include/asm/uaccess.h
index 7cf799d..ff4cf9d 100644
--- a/arch/parisc/include/asm/uaccess.h
+++ b/arch/parisc/include/asm/uaccess.h
@@ -7,6 +7,7 @@
#include <asm/page.h>
#include <asm/system.h>
#include <asm/cache.h>
+#include <asm/errno.h>
#include <asm-generic/uaccess-unaligned.h>
#define VERIFY_READ 0
@@ -234,13 +235,35 @@ extern long lstrnlen_user(const char __user *,long);
unsigned long copy_to_user(void __user *dst, const void *src, unsigned long len);
#define __copy_to_user copy_to_user
-unsigned long copy_from_user(void *dst, const void __user *src, unsigned long len);
-#define __copy_from_user copy_from_user
+unsigned long __copy_from_user(void *dst, const void __user *src, unsigned long len);
unsigned long copy_in_user(void __user *dst, const void __user *src, unsigned long len);
#define __copy_in_user copy_in_user
#define __copy_to_user_inatomic __copy_to_user
#define __copy_from_user_inatomic __copy_from_user
+extern void copy_from_user_overflow(void)
+#ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
+ __compiletime_error("copy_from_user() buffer size is not provably correct")
+#else
+ __compiletime_warning("copy_from_user() buffer size is not provably correct")
+#endif
+;
+
+static inline unsigned long __must_check copy_from_user(void *to,
+ const void __user *from,
+ unsigned long n)
+{
+ int sz = __compiletime_object_size(to);
+ int ret = -EFAULT;
+
+ if (likely(sz == -1 || !__builtin_constant_p(n) || sz >= n))
+ ret = __copy_from_user(to, from, n);
+ else
+ copy_from_user_overflow();
+
+ return ret;
+}
+
struct pt_regs;
int fixup_exception(struct pt_regs *regs);
diff --git a/arch/parisc/lib/memcpy.c b/arch/parisc/lib/memcpy.c
index abf41f4..1dbca5c 100644
--- a/arch/parisc/lib/memcpy.c
+++ b/arch/parisc/lib/memcpy.c
@@ -475,7 +475,8 @@ unsigned long copy_to_user(void __user *dst, const void *src, unsigned long len)
return pa_memcpy((void __force *)dst, src, len);
}
-unsigned long copy_from_user(void *dst, const void __user *src, unsigned long len)
+EXPORT_SYMBOL(__copy_from_user);
+unsigned long __copy_from_user(void *dst, const void __user *src, unsigned long len)
{
mtsp(get_user_space(), 1);
mtsp(get_kernel_space(), 2);
--
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