diff options
| -rw-r--r-- | arch/parisc/Kconfig.debug | 14 | ||||
| -rw-r--r-- | arch/parisc/include/asm/uaccess.h | 27 | ||||
| -rw-r--r-- | arch/parisc/lib/memcpy.c | 3 |
3 files changed, 41 insertions, 3 deletions
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); |
