[PATCH 15/23] maccess: remove strncpy_from_unsafe

Christoph Hellwig
2020-05-21T15:25:24Z

All users are gone now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
include/linux/uaccess.h | 1 -
mm/maccess.c | 39 +--------------------------------------
2 files changed, 1 insertion(+), 39 deletions(-)

diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index 65a37ae3b8871..d7d98ff345b3d 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -311,7 +311,6 @@ extern long probe_user_read(void *dst, const void __user *src, size_t size);
extern long notrace probe_kernel_write(void *dst, const void *src, size_t size);
extern long notrace probe_user_write(void __user *dst, const void *src, size_t size);

-extern long strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count);
long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr,
long count);

diff --git a/mm/maccess.c b/mm/maccess.c
index 6116742608217..df82fde34307f 100644
--- a/mm/maccess.c
+++ b/mm/maccess.c
@@ -8,8 +8,6 @@

static long __probe_kernel_read(void *dst, const void *src, size_t size,
bool strict);
-static long __strncpy_from_unsafe(char *dst, const void *unsafe_addr,
- long count, bool strict);

bool __weak probe_kernel_read_allowed(const void *unsafe_src, size_t size,
bool strict)
@@ -156,35 +154,6 @@ long probe_user_write(void __user *dst, const void *src, size_t size)
return 0;
}

-/**
- * strncpy_from_unsafe: - 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 @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.
- *
- * Same as strncpy_from_kernel_nofault() except that for architectures with
- * not fully separated user and kernel address spaces this function also works
- * for user address tanges.
- *
- * DO NOT USE THIS FUNCTION - it is broken on architectures with entirely
- * separate kernel and user address spaces, and also a bad idea otherwise.
- */
-long strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count)
-{
- return __strncpy_from_unsafe(dst, unsafe_addr, count, false);
-}
-
/**
* strncpy_from_kernel_nofault: - Copy a NUL terminated string from unsafe
* address.
@@ -204,12 +173,6 @@ long strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count)
* 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)
-{
- return __strncpy_from_unsafe(dst, unsafe_addr, count, true);
-}
-
-static long __strncpy_from_unsafe(char *dst, const void *unsafe_addr,
- long count, bool strict)
{
mm_segment_t old_fs = get_fs();
const void *src = unsafe_addr;
@@ -217,7 +180,7 @@ static long __strncpy_from_unsafe(char *dst, const void *unsafe_addr,

if (unlikely(count <= 0))
return 0;
- if (!probe_kernel_read_allowed(unsafe_addr, count, strict))
+ if (!probe_kernel_read_allowed(unsafe_addr, count, true))
return -EFAULT;

set_fs(KERNEL_DS);
--
2.26.2