diff options
Diffstat (limited to 'arch/arm/include/asm/uaccess.h')
| -rw-r--r-- | arch/arm/include/asm/uaccess.h | 49 |
1 files changed, 43 insertions, 6 deletions
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h index 7b17460127fd..0f6c6b873bc5 100644 --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -99,6 +99,14 @@ extern int __put_user_bad(void); static inline void set_fs(mm_segment_t fs) { current_thread_info()->addr_limit = fs; + + /* + * Prevent a mispredicted conditional call to set_fs from forwarding + * the wrong address limit to access_ok under speculation. + */ + dsb(nsh); + isb(); + modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER); } @@ -122,6 +130,32 @@ static inline void set_fs(mm_segment_t fs) __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL)) /* + * Sanitise a uaccess pointer such that it becomes NULL if addr+size + * is above the current addr_limit. + */ +#define uaccess_mask_range_ptr(ptr, size) \ + ((__typeof__(ptr))__uaccess_mask_range_ptr(ptr, size)) +static inline void __user *__uaccess_mask_range_ptr(const void __user *ptr, + size_t size) +{ + void __user *safe_ptr = (void __user *)ptr; + unsigned long tmp; + + asm volatile( + " sub %1, %3, #1\n" + " subs %1, %1, %0\n" + " addhs %1, %1, #1\n" + " subhss %1, %1, %2\n" + " movlo %0, #0\n" + : "+r" (safe_ptr), "=&r" (tmp) + : "r" (size), "r" (current_thread_info()->addr_limit) + : "cc"); + + csdb(); + return safe_ptr; +} + +/* * Single-value transfer routines. They automatically use the right * size if we just have the right pointer type. Note that the functions * which read from user space (*get_*) need to take care not to leak @@ -392,6 +426,14 @@ do { \ __pu_err; \ }) +#ifdef CONFIG_CPU_SPECTRE +/* + * When mitigating Spectre variant 1.1, all accessors need to include + * verification of the address space. + */ +#define __put_user(x, ptr) put_user(x, ptr) + +#else #define __put_user(x, ptr) \ ({ \ long __pu_err = 0; \ @@ -399,12 +441,6 @@ do { \ __pu_err; \ }) -#define __put_user_error(x, ptr, err) \ -({ \ - __put_user_switch((x), (ptr), (err), __put_user_nocheck); \ - (void) 0; \ -}) - #define __put_user_nocheck(x, __pu_ptr, __err, __size) \ do { \ unsigned long __pu_addr = (unsigned long)__pu_ptr; \ @@ -484,6 +520,7 @@ do { \ : "r" (x), "i" (-EFAULT) \ : "cc") +#endif /* !CONFIG_CPU_SPECTRE */ #ifdef CONFIG_MMU extern unsigned long __must_check |