diff options
| -rw-r--r-- | arch/x86/include/asm/uaccess.h | 98 | ||||
| -rw-r--r-- | arch/x86/include/asm/uaccess_32.h | 29 | ||||
| -rw-r--r-- | arch/x86/include/asm/uaccess_64.h | 28 | ||||
| -rw-r--r-- | arch/x86/lib/usercopy_32.c | 8 |
4 files changed, 101 insertions, 62 deletions
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 5838fa911aa0..8ec57c07b125 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -542,5 +542,103 @@ extern struct movsl_mask { # include <asm/uaccess_64.h> #endif +unsigned long __must_check _copy_from_user(void *to, const void __user *from, + unsigned n); +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() + +#else + +static inline void +__copy_from_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 +copy_from_user(void *to, const void __user *from, unsigned long n) +{ + int sz = __compiletime_object_size(to); + + might_fault(); + + /* + * 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)) + n = _copy_from_user(to, from, n); + else if(__builtin_constant_p(n)) + copy_from_user_overflow(); + else + __copy_from_user_overflow(sz, n); + + return n; +} + +static inline unsigned long __must_check +copy_to_user(void __user *to, const void *from, unsigned long n) +{ + int sz = __compiletime_object_size(from); + + might_fault(); + + /* See the comment in copy_from_user() above. */ + if (likely(sz < 0 || sz >= n)) + n = _copy_to_user(to, from, n); + else if(__builtin_constant_p(n)) + copy_to_user_overflow(); + else + __copy_to_user_overflow(sz, n); + + return n; +} + +#undef __copy_from_user_overflow +#undef __copy_to_user_overflow + #endif /* _ASM_X86_UACCESS_H */ diff --git a/arch/x86/include/asm/uaccess_32.h b/arch/x86/include/asm/uaccess_32.h index 7f760a9f1f61..3c03a5de64d3 100644 --- a/arch/x86/include/asm/uaccess_32.h +++ b/arch/x86/include/asm/uaccess_32.h @@ -184,33 +184,4 @@ __copy_from_user_inatomic_nocache(void *to, const void __user *from, return __copy_from_user_ll_nocache_nozero(to, from, n); } -unsigned long __must_check copy_to_user(void __user *to, - const void *from, unsigned long n); -unsigned long __must_check _copy_from_user(void *to, - const void __user *from, - unsigned long n); - - -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); - - if (likely(sz == -1 || sz >= n)) - n = _copy_from_user(to, from, n); - else - copy_from_user_overflow(); - - return n; -} - #endif /* _ASM_X86_UACCESS_32_H */ diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h index 4f7923dd0007..0acae710fa00 100644 --- a/arch/x86/include/asm/uaccess_64.h +++ b/arch/x86/include/asm/uaccess_64.h @@ -46,36 +46,8 @@ copy_user_generic(void *to, const void *from, unsigned len) } __must_check unsigned long -_copy_to_user(void __user *to, const void *from, unsigned len); -__must_check unsigned long -_copy_from_user(void *to, const void __user *from, unsigned len); -__must_check unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len); -static inline unsigned long __must_check copy_from_user(void *to, - const void __user *from, - unsigned long n) -{ - int sz = __compiletime_object_size(to); - - might_fault(); - if (likely(sz == -1 || sz >= n)) - n = _copy_from_user(to, from, n); -#ifdef CONFIG_DEBUG_VM - else - WARN(1, "Buffer overflow detected!\n"); -#endif - return n; -} - -static __always_inline __must_check -int copy_to_user(void __user *dst, const void *src, unsigned size) -{ - might_fault(); - - return _copy_to_user(dst, src, size); -} - static __always_inline __must_check int __copy_from_user(void *dst, const void __user *src, unsigned size) { diff --git a/arch/x86/lib/usercopy_32.c b/arch/x86/lib/usercopy_32.c index 3eb18acd0e40..e2f5e21c03b3 100644 --- a/arch/x86/lib/usercopy_32.c +++ b/arch/x86/lib/usercopy_32.c @@ -654,14 +654,13 @@ EXPORT_SYMBOL(__copy_from_user_ll_nocache_nozero); * Returns number of bytes that could not be copied. * On success, this will be zero. */ -unsigned long -copy_to_user(void __user *to, const void *from, unsigned long n) +unsigned long _copy_to_user(void __user *to, const void *from, unsigned n) { if (access_ok(VERIFY_WRITE, to, n)) n = __copy_to_user(to, from, n); return n; } -EXPORT_SYMBOL(copy_to_user); +EXPORT_SYMBOL(_copy_to_user); /** * copy_from_user: - Copy a block of data from user space. @@ -679,8 +678,7 @@ EXPORT_SYMBOL(copy_to_user); * If some data could not be copied, this function will pad the copied * data to the requested size using zero bytes. */ -unsigned long -_copy_from_user(void *to, const void __user *from, unsigned long n) +unsigned long _copy_from_user(void *to, const void __user *from, unsigned n) { if (access_ok(VERIFY_READ, from, n)) n = __copy_from_user(to, from, n); |
