Re: [PATCH][MIPS] add return value check to user_termio_to_kernel_termios()

[Ralf Baechle <ralf@linux-mips.org>]

On Sun, Jan 25, 2009 at 10:45:57PM +0900, Yoichi Yuasa wrote:

> diff -pruN -X /home/yuasa/Memo/dontdiff 
> linux-orig/arch/mips/include/asm/termios.h 
> linux/arch/mips/include/asm/termios.h
> --- linux-orig/arch/mips/include/asm/termios.h        2008-10-19 
> 22:33:14.114377349 +0900
> +++ linux/arch/mips/include/asm/termios.h     2008-10-19 22:41:25.322369698 
> +0900
> @@ -97,14 +97,14 @@ struct termio {
>  #define user_termio_to_kernel_termios(termios, termio) \
>  ({ \
>       unsigned short tmp; \
> -     get_user(tmp, &(termio)->c_iflag); \
> -     (termios)->c_iflag = (0xffff0000 & ((termios)->c_iflag)) | tmp; \
> -     get_user(tmp, &(termio)->c_oflag); \
> -     (termios)->c_oflag = (0xffff0000 & ((termios)->c_oflag)) | tmp; \
> -     get_user(tmp, &(termio)->c_cflag); \
> -     (termios)->c_cflag = (0xffff0000 & ((termios)->c_cflag)) | tmp; \
> -     get_user(tmp, &(termio)->c_lflag); \
> -     (termios)->c_lflag = (0xffff0000 & ((termios)->c_lflag)) | tmp; \
> +     if (!get_user(tmp, &(termio)->c_iflag)) \
> +             (termios)->c_iflag = (0xffff0000 & ((termios)->c_iflag)) | tmp; 
> \
> +     if (!get_user(tmp, &(termio)->c_oflag)) \
> +             (termios)->c_oflag = (0xffff0000 & ((termios)->c_oflag)) | tmp; 
> \
> +     if (!get_user(tmp, &(termio)->c_cflag)) \
> +             (termios)->c_cflag = (0xffff0000 & ((termios)->c_cflag)) | tmp; 
> \
> +     if (!get_user(tmp, &(termio)->c_lflag)) \
> +             (termios)->c_lflag = (0xffff0000 & ((termios)->c_lflag)) | tmp; 
> \
>       get_user((termios)->c_line, &(termio)->c_line); \
>       copy_from_user((termios)->c_cc, (termio)->c_cc, NCC); \

Duh...  That sort of trivial thing is not fatal but just shouldn't
happen.  And other architectures have the same bug even.  Your patch
leaves the last get_user and the copy_from_user return values unchecked.
I'll sort that out.

Thanks for reporting and patch!

  Ralf