1 // SPDX-License-Identifier: GPL-2.0-only 2 3 #include <linux/uaccess.h> 4 #include <linux/kernel.h> 5 6 #ifdef CONFIG_X86_64 7 static __always_inline u64 canonical_address(u64 vaddr, u8 vaddr_bits) 8 { 9 return ((s64)vaddr << (64 - vaddr_bits)) >> (64 - vaddr_bits); 10 } 11 12 static __always_inline bool invalid_probe_range(u64 vaddr) 13 { 14 /* 15 * Range covering the highest possible canonical userspace address 16 * as well as non-canonical address range. For the canonical range 17 * we also need to include the userspace guard page. 18 */ 19 return vaddr < TASK_SIZE_MAX + PAGE_SIZE || 20 canonical_address(vaddr, boot_cpu_data.x86_virt_bits) != vaddr; 21 } 22 #else 23 static __always_inline bool invalid_probe_range(u64 vaddr) 24 { 25 return vaddr < TASK_SIZE_MAX; 26 } 27 #endif 28 29 long probe_kernel_read_strict(void *dst, const void *src, size_t size) 30 { 31 if (unlikely(invalid_probe_range((unsigned long)src))) 32 return -EFAULT; 33 34 return __probe_kernel_read(dst, src, size); 35 } 36 37 long strncpy_from_unsafe_strict(char *dst, const void *unsafe_addr, long count) 38 { 39 if (unlikely(invalid_probe_range((unsigned long)unsafe_addr))) 40 return -EFAULT; 41 42 return __strncpy_from_unsafe(dst, unsafe_addr, count); 43 } 44