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-rw-r--r--arch/x86/include/asm/uaccess.h79
1 files changed, 16 insertions, 63 deletions
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index a0ae610b9280..2131c4ce7d8a 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -433,7 +433,11 @@ do { \
#define __get_user_asm_ex(x, addr, itype, rtype, ltype) \
asm volatile("1: mov"itype" %1,%"rtype"0\n" \
"2:\n" \
- _ASM_EXTABLE_EX(1b, 2b) \
+ ".section .fixup,\"ax\"\n" \
+ "3:xor"itype" %"rtype"0,%"rtype"0\n" \
+ " jmp 2b\n" \
+ ".previous\n" \
+ _ASM_EXTABLE_EX(1b, 3b) \
: ltype(x) : "m" (__m(addr)))
#define __put_user_nocheck(x, ptr, size) \
@@ -697,44 +701,15 @@ unsigned long __must_check _copy_from_user(void *to, const void __user *from,
unsigned long __must_check _copy_to_user(void __user *to, const void *from,
unsigned n);
-#ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
-# define copy_user_diag __compiletime_error
-#else
-# define copy_user_diag __compiletime_warning
-#endif
-
-extern void copy_user_diag("copy_from_user() buffer size is too small")
-copy_from_user_overflow(void);
-extern void copy_user_diag("copy_to_user() buffer size is too small")
-copy_to_user_overflow(void) __asm__("copy_from_user_overflow");
-
-#undef copy_user_diag
-
-#ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
-
-extern void
-__compiletime_warning("copy_from_user() buffer size is not provably correct")
-__copy_from_user_overflow(void) __asm__("copy_from_user_overflow");
-#define __copy_from_user_overflow(size, count) __copy_from_user_overflow()
-
-extern void
-__compiletime_warning("copy_to_user() buffer size is not provably correct")
-__copy_to_user_overflow(void) __asm__("copy_from_user_overflow");
-#define __copy_to_user_overflow(size, count) __copy_to_user_overflow()
+extern void __compiletime_error("usercopy buffer size is too small")
+__bad_copy_user(void);
-#else
-
-static inline void
-__copy_from_user_overflow(int size, unsigned long count)
+static inline void copy_user_overflow(int size, unsigned long count)
{
WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
}
-#define __copy_to_user_overflow __copy_from_user_overflow
-
-#endif
-
-static inline unsigned long __must_check
+static __always_inline unsigned long __must_check
copy_from_user(void *to, const void __user *from, unsigned long n)
{
int sz = __compiletime_object_size(to);
@@ -743,36 +718,18 @@ copy_from_user(void *to, const void __user *from, unsigned long n)
kasan_check_write(to, n);
- /*
- * While we would like to have the compiler do the checking for us
- * even in the non-constant size case, any false positives there are
- * a problem (especially when DEBUG_STRICT_USER_COPY_CHECKS, but even
- * without - the [hopefully] dangerous looking nature of the warning
- * would make people go look at the respecitive call sites over and
- * over again just to find that there's no problem).
- *
- * And there are cases where it's just not realistic for the compiler
- * to prove the count to be in range. For example when multiple call
- * sites of a helper function - perhaps in different source files -
- * all doing proper range checking, yet the helper function not doing
- * so again.
- *
- * Therefore limit the compile time checking to the constant size
- * case, and do only runtime checking for non-constant sizes.
- */
-
if (likely(sz < 0 || sz >= n)) {
check_object_size(to, n, false);
n = _copy_from_user(to, from, n);
- } else if (__builtin_constant_p(n))
- copy_from_user_overflow();
+ } else if (!__builtin_constant_p(n))
+ copy_user_overflow(sz, n);
else
- __copy_from_user_overflow(sz, n);
+ __bad_copy_user();
return n;
}
-static inline unsigned long __must_check
+static __always_inline unsigned long __must_check
copy_to_user(void __user *to, const void *from, unsigned long n)
{
int sz = __compiletime_object_size(from);
@@ -781,21 +738,17 @@ copy_to_user(void __user *to, const void *from, unsigned long n)
might_fault();
- /* See the comment in copy_from_user() above. */
if (likely(sz < 0 || sz >= n)) {
check_object_size(from, n, true);
n = _copy_to_user(to, from, n);
- } else if (__builtin_constant_p(n))
- copy_to_user_overflow();
+ } else if (!__builtin_constant_p(n))
+ copy_user_overflow(sz, n);
else
- __copy_to_user_overflow(sz, n);
+ __bad_copy_user();
return n;
}
-#undef __copy_from_user_overflow
-#undef __copy_to_user_overflow
-
/*
* We rely on the nested NMI work to allow atomic faults from the NMI path; the
* nested NMI paths are careful to preserve CR2.
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