diff options
| -rw-r--r-- | arch/arm64/include/asm/uaccess.h | 23 |
1 files changed, 10 insertions, 13 deletions
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 28f665e0975a..1f21190d4db5 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -30,23 +30,20 @@ static inline int __access_ok(const void __user *ptr, unsigned long size); /* * Test whether a block of memory is a valid user space address. - * Returns 1 if the range is valid, 0 otherwise. * - * This is equivalent to the following test: - * (u65)addr + (u65)size <= (u65)TASK_SIZE_MAX + * We only care that the address cannot reach the kernel mapping, and + * that an invalid address will fault. */ -static inline int access_ok(const void __user *addr, unsigned long size) +static inline int access_ok(const void __user *p, unsigned long size) { - /* - * Asynchronous I/O running in a kernel thread does not have the - * TIF_TAGGED_ADDR flag of the process owning the mm, so always untag - * the user address before checking. - */ - if (IS_ENABLED(CONFIG_ARM64_TAGGED_ADDR_ABI) && - (current->flags & PF_KTHREAD || test_thread_flag(TIF_TAGGED_ADDR))) - addr = untagged_addr(addr); + unsigned long addr = (unsigned long)p; + + /* Only bit 55 of the address matters */ + addr |= addr+size; + addr = (addr >> 55) & 1; + size >>= 55; - return likely(__access_ok(addr, size)); + return !(addr | size); } #define access_ok access_ok |