From a1599d819d3dd1a50d1c11bc9cb8e5d751086f64 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 18 Aug 2016 19:34:00 -0400 Subject: [PATCH] cris: buggered copy_from_user/copy_to_user/clear_user commit eb47e0293baaa3044022059f1fa9ff474bfe35cb upstream. * copy_from_user() on access_ok() failure ought to zero the destination * none of those primitives should skip the access_ok() check in case of small constant size. Acked-by: Jesper Nilsson Signed-off-by: Al Viro [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- arch/cris/include/asm/uaccess.h | 71 +++++++++++++++------------------ 1 file changed, 32 insertions(+), 39 deletions(-) diff --git a/arch/cris/include/asm/uaccess.h b/arch/cris/include/asm/uaccess.h index 914540801c5e..93bfa8acc38b 100644 --- a/arch/cris/include/asm/uaccess.h +++ b/arch/cris/include/asm/uaccess.h @@ -176,30 +176,6 @@ extern unsigned long __copy_user(void __user *to, const void *from, unsigned lon extern unsigned long __copy_user_zeroing(void *to, const void __user *from, unsigned long n); extern unsigned long __do_clear_user(void __user *to, unsigned long n); -static inline unsigned long -__generic_copy_to_user(void __user *to, const void *from, unsigned long n) -{ - if (access_ok(VERIFY_WRITE, to, n)) - return __copy_user(to,from,n); - return n; -} - -static inline unsigned long -__generic_copy_from_user(void *to, const void __user *from, unsigned long n) -{ - if (access_ok(VERIFY_READ, from, n)) - return __copy_user_zeroing(to,from,n); - return n; -} - -static inline unsigned long -__generic_clear_user(void __user *to, unsigned long n) -{ - if (access_ok(VERIFY_WRITE, to, n)) - return __do_clear_user(to,n); - return n; -} - static inline long __strncpy_from_user(char *dst, const char __user *src, long count) { @@ -262,7 +238,7 @@ __constant_copy_from_user(void *to, const void __user *from, unsigned long n) else if (n == 24) __asm_copy_from_user_24(to, from, ret); else - ret = __generic_copy_from_user(to, from, n); + ret = __copy_user_zeroing(to, from, n); return ret; } @@ -312,7 +288,7 @@ __constant_copy_to_user(void __user *to, const void *from, unsigned long n) else if (n == 24) __asm_copy_to_user_24(to, from, ret); else - ret = __generic_copy_to_user(to, from, n); + ret = __copy_user(to, from, n); return ret; } @@ -344,26 +320,43 @@ __constant_clear_user(void __user *to, unsigned long n) else if (n == 24) __asm_clear_24(to, ret); else - ret = __generic_clear_user(to, n); + ret = __do_clear_user(to, n); return ret; } -#define clear_user(to, n) \ -(__builtin_constant_p(n) ? \ - __constant_clear_user(to, n) : \ - __generic_clear_user(to, n)) +static inline size_t clear_user(void __user *to, size_t n) +{ + if (unlikely(!access_ok(VERIFY_WRITE, to, n))) + return n; + if (__builtin_constant_p(n)) + return __constant_clear_user(to, n); + else + return __do_clear_user(to, n); +} -#define copy_from_user(to, from, n) \ -(__builtin_constant_p(n) ? \ - __constant_copy_from_user(to, from, n) : \ - __generic_copy_from_user(to, from, n)) +static inline size_t copy_from_user(void *to, const void __user *from, size_t n) +{ + if (unlikely(!access_ok(VERIFY_READ, from, n))) { + memset(to, 0, n); + return n; + } + if (__builtin_constant_p(n)) + return __constant_copy_from_user(to, from, n); + else + return __copy_user_zeroing(to, from, n); +} -#define copy_to_user(to, from, n) \ -(__builtin_constant_p(n) ? \ - __constant_copy_to_user(to, from, n) : \ - __generic_copy_to_user(to, from, n)) +static inline size_t copy_to_user(void __user *to, const void *from, size_t n) +{ + if (unlikely(!access_ok(VERIFY_WRITE, to, n))) + return n; + if (__builtin_constant_p(n)) + return __constant_copy_to_user(to, from, n); + else + return __copy_user(to, from, n); +} /* We let the __ versions of copy_from/to_user inline, because they're often * used in fast paths and have only a small space overhead. -- 2.39.2