diff options
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/Kconfig | 1 | ||||
| -rw-r--r-- | arch/x86/include/asm/uaccess.h | 1 | ||||
| -rw-r--r-- | arch/x86/lib/usercopy.c | 97 |
3 files changed, 2 insertions, 97 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 81c3e8be789a..3220d44e24d0 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -93,6 +93,7 @@ config X86 select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) select GENERIC_TIME_VSYSCALL if X86_64 select KTIME_SCALAR if X86_32 + select GENERIC_STRNCPY_FROM_USER config INSTRUCTION_DECODER def_bool (KPROBES || PERF_EVENTS || UPROBES) diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 851fe0dc13bc..1354facd8f63 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -32,6 +32,7 @@ #define segment_eq(a, b) ((a).seg == (b).seg) +#define user_addr_max() (current_thread_info()->addr_limit.seg) #define __addr_ok(addr) \ ((unsigned long __force)(addr) < \ (current_thread_info()->addr_limit.seg)) diff --git a/arch/x86/lib/usercopy.c b/arch/x86/lib/usercopy.c index 2e4e4b02c37a..f61ee67ec00f 100644 --- a/arch/x86/lib/usercopy.c +++ b/arch/x86/lib/usercopy.c @@ -43,100 +43,3 @@ copy_from_user_nmi(void *to, const void __user *from, unsigned long n) return len; } EXPORT_SYMBOL_GPL(copy_from_user_nmi); - -/* - * Do a strncpy, return length of string without final '\0'. - * 'count' is the user-supplied count (return 'count' if we - * hit it), 'max' is the address space maximum (and we return - * -EFAULT if we hit it). - */ -static inline long do_strncpy_from_user(char *dst, const char __user *src, long count, unsigned long max) -{ - long res = 0; - - /* - * Truncate 'max' to the user-specified limit, so that - * we only have one limit we need to check in the loop - */ - if (max > count) - max = count; - - while (max >= sizeof(unsigned long)) { - unsigned long c, mask; - - /* Fall back to byte-at-a-time if we get a page fault */ - if (unlikely(__get_user(c,(unsigned long __user *)(src+res)))) - break; - mask = has_zero(c); - if (mask) { - mask = (mask - 1) & ~mask; - mask >>= 7; - *(unsigned long *)(dst+res) = c & mask; - return res + count_masked_bytes(mask); - } - *(unsigned long *)(dst+res) = c; - res += sizeof(unsigned long); - max -= sizeof(unsigned long); - } - - while (max) { - char c; - - if (unlikely(__get_user(c,src+res))) - return -EFAULT; - dst[res] = c; - if (!c) - return res; - res++; - max--; - } - - /* - * Uhhuh. We hit 'max'. But was that the user-specified maximum - * too? If so, that's ok - we got as much as the user asked for. - */ - if (res >= count) - return res; - - /* - * Nope: we hit the address space limit, and we still had more - * characters the caller would have wanted. That's an EFAULT. - */ - return -EFAULT; -} - -/** - * strncpy_from_user: - Copy a NUL terminated string from userspace. - * @dst: Destination address, in kernel space. This buffer must be at - * least @count bytes long. - * @src: Source address, in user space. - * @count: Maximum number of bytes to copy, including the trailing NUL. - * - * Copies a NUL-terminated string from userspace to kernel space. - * - * On success, returns the length of the string (not including the trailing - * NUL). - * - * If access to userspace fails, returns -EFAULT (some data may have been - * copied). - * - * If @count is smaller than the length of the string, copies @count bytes - * and returns @count. - */ -long -strncpy_from_user(char *dst, const char __user *src, long count) -{ - unsigned long max_addr, src_addr; - - if (unlikely(count <= 0)) - return 0; - - max_addr = current_thread_info()->addr_limit.seg; - src_addr = (unsigned long)src; - if (likely(src_addr < max_addr)) { - unsigned long max = max_addr - src_addr; - return do_strncpy_from_user(dst, src, count, max); - } - return -EFAULT; -} -EXPORT_SYMBOL(strncpy_from_user); |