From: Christoph Hellwig <hch@xxxxxx> Subject: maccess: remove strncpy_from_unsafe All users are gone now. Link: http://lkml.kernel.org/r/20200521152301.2587579-16-hch@xxxxxx Signed-off-by: Christoph Hellwig <hch@xxxxxx> Cc: Alexei Starovoitov <ast@xxxxxxxxxx> Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxx> Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/uaccess.h | 1 mm/maccess.c | 39 -------------------------------------- 2 files changed, 1 insertion(+), 39 deletions(-) --- a/include/linux/uaccess.h~maccess-remove-strncpy_from_unsafe +++ a/include/linux/uaccess.h @@ -311,7 +311,6 @@ extern long probe_user_read(void *dst, c 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); --- a/mm/maccess.c~maccess-remove-strncpy_from_unsafe +++ a/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) @@ -158,35 +156,6 @@ long probe_user_write(void __user *dst, EXPORT_SYMBOL_GPL(probe_user_write); /** - * 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. * @dst: Destination address, in kernel space. This buffer must be at @@ -206,19 +175,13 @@ long strncpy_from_unsafe(char *dst, cons */ 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; long ret; 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); _
