long count);
long strnlen_user_nofault(const void __user *unsafe_addr, long count);
+#ifndef __get_kernel_nofault
+#define __get_kernel_nofault(dst, src, type, label) \
+do { \
+ type __user *p = (type __force __user *)(src); \
+ type data; \
+ if (__get_user(data, p)) \
+ goto label; \
+ *(type *)dst = data; \
+} while (0)
+
+#define __put_kernel_nofault(dst, src, type, label) \
+do { \
+ type __user *p = (type __force __user *)(dst); \
+ type data = *(type *)src; \
+ if (__put_user(data, p)) \
+ goto label; \
+} while (0)
+#endif
+
/**
* get_kernel_nofault(): safely attempt to read from a location
* @val: read into this variable
return true;
}
-#ifdef HAVE_GET_KERNEL_NOFAULT
-
#define copy_from_kernel_nofault_loop(dst, src, len, type, err_label) \
while (len >= sizeof(type)) { \
__get_kernel_nofault(dst, src, type, err_label); \
dst[-1] = '\0';
return -EFAULT;
}
-#else /* HAVE_GET_KERNEL_NOFAULT */
-/**
- * copy_from_kernel_nofault(): safely attempt to read from kernel-space
- * @dst: pointer to the buffer that shall take the data
- * @src: address to read from
- * @size: size of the data chunk
- *
- * Safely read from kernel address @src to the buffer at @dst. If a kernel
- * fault happens, handle that and return -EFAULT. If @src is not a valid kernel
- * address, return -ERANGE.
- *
- * We ensure that the copy_from_user is executed in atomic context so that
- * do_page_fault() doesn't attempt to take mmap_lock. This makes
- * copy_from_kernel_nofault() suitable for use within regions where the caller
- * already holds mmap_lock, or other locks which nest inside mmap_lock.
- */
-long copy_from_kernel_nofault(void *dst, const void *src, size_t size)
-{
- long ret;
- mm_segment_t old_fs = get_fs();
-
- if (!copy_from_kernel_nofault_allowed(src, size))
- return -ERANGE;
-
- set_fs(KERNEL_DS);
- pagefault_disable();
- ret = __copy_from_user_inatomic(dst, (__force const void __user *)src,
- size);
- pagefault_enable();
- set_fs(old_fs);
-
- if (ret)
- return -EFAULT;
- return 0;
-}
-EXPORT_SYMBOL_GPL(copy_from_kernel_nofault);
-
-/**
- * copy_to_kernel_nofault(): safely attempt to write to a location
- * @dst: address to write to
- * @src: pointer to the data that shall be written
- * @size: size of the data chunk
- *
- * Safely write to address @dst from the buffer at @src. If a kernel fault
- * happens, handle that and return -EFAULT.
- */
-long copy_to_kernel_nofault(void *dst, const void *src, size_t size)
-{
- long ret;
- mm_segment_t old_fs = get_fs();
-
- set_fs(KERNEL_DS);
- pagefault_disable();
- ret = __copy_to_user_inatomic((__force void __user *)dst, src, size);
- pagefault_enable();
- set_fs(old_fs);
-
- if (ret)
- return -EFAULT;
- return 0;
-}
-
-/**
- * strncpy_from_kernel_nofault: - Copy a NUL terminated string from unsafe
- * address.
- * @dst: Destination address, in kernel space. This buffer must be at
- * least @count bytes long.
- * @unsafe_addr: Unsafe address.
- * @count: Maximum number of bytes to copy, including the trailing NUL.
- *
- * Copies a NUL-terminated string from unsafe address to kernel buffer.
- *
- * On success, returns the length of the string INCLUDING the trailing NUL.
- *
- * If access fails, returns -EFAULT (some data may have been copied and the
- * trailing NUL added). If @unsafe_addr is not a valid kernel address, return
- * -ERANGE.
- *
- * If @count is smaller than the length of the string, copies @count-1 bytes,
- * sets the last byte of @dst buffer to NUL and returns @count.
- */
-long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, long count)
-{
- mm_segment_t old_fs = get_fs();
- const void *src = unsafe_addr;
- long ret;
-
- if (unlikely(count <= 0))
- return 0;
- if (!copy_from_kernel_nofault_allowed(unsafe_addr, count))
- return -ERANGE;
-
- set_fs(KERNEL_DS);
- pagefault_disable();
-
- do {
- ret = __get_user(*dst++, (const char __user __force *)src++);
- } while (dst[-1] && ret == 0 && src - unsafe_addr < count);
-
- dst[-1] = '\0';
- pagefault_enable();
- set_fs(old_fs);
-
- return ret ? -EFAULT : src - unsafe_addr;
-}
-#endif /* HAVE_GET_KERNEL_NOFAULT */
/**
* copy_from_user_nofault(): safely attempt to read from a user-space location
projects / linux.git / commitdiff