One-element arrays are being deprecated[1]. Replace the one-element arrays with simple value types 'char reserved_char' and 'compat_int_t reserved'[2], once it seems these are just placeholders for alignment.
Also, while there, use the preferred form for passing a size of a struct. The alternative form where struct name is spelled out hurts readability and introduces an opportunity for a bug when the variable type is changed but the corresponding sizeof that is passed as argument is not. Lastly, fix the checkpatch.pl warnings below: ERROR: code indent should use tabs where possible + char reserved_char;$ WARNING: please, no spaces at the start of a line + char reserved_char;$ ERROR: code indent should use tabs where possible + compat_int_t reserved;$ WARNING: please, no spaces at the start of a line + compat_int_t reserved;$ [1] https://github.com/KSPP/linux/issues/79 [2] https://github.com/KSPP/linux/issues/86 Tested-by: kernel test robot <[email protected]> Link: https://github.com/GustavoARSilva/linux-hardening/blob/master/cii/0-day/tty-20200716.md Acked-by: Jiri Slaby <[email protected]> Signed-off-by: Gustavo A. R. Silva <[email protected]> --- Changes in v2: - Fix indentation issues in struct serial_struct32. - Add Jiri's Acked-by. drivers/tty/tty_io.c | 42 +++++++++++++++++++++--------------------- 1 file changed, 21 insertions(+), 21 deletions(-) diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 5a6f36b391d9..bb74c2ffcced 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -2673,25 +2673,25 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg) #ifdef CONFIG_COMPAT struct serial_struct32 { - compat_int_t type; - compat_int_t line; - compat_uint_t port; - compat_int_t irq; - compat_int_t flags; - compat_int_t xmit_fifo_size; - compat_int_t custom_divisor; - compat_int_t baud_base; - unsigned short close_delay; - char io_type; - char reserved_char[1]; - compat_int_t hub6; - unsigned short closing_wait; /* time to wait before closing */ - unsigned short closing_wait2; /* no longer used... */ - compat_uint_t iomem_base; - unsigned short iomem_reg_shift; - unsigned int port_high; - /* compat_ulong_t iomap_base FIXME */ - compat_int_t reserved[1]; + compat_int_t type; + compat_int_t line; + compat_uint_t port; + compat_int_t irq; + compat_int_t flags; + compat_int_t xmit_fifo_size; + compat_int_t custom_divisor; + compat_int_t baud_base; + unsigned short close_delay; + char io_type; + char reserved_char; + compat_int_t hub6; + unsigned short closing_wait; /* time to wait before closing */ + unsigned short closing_wait2; /* no longer used... */ + compat_uint_t iomem_base; + unsigned short iomem_reg_shift; + unsigned int port_high; + /* compat_ulong_t iomap_base FIXME */ + compat_int_t reserved; }; static int compat_tty_tiocsserial(struct tty_struct *tty, @@ -2705,7 +2705,7 @@ static int compat_tty_tiocsserial(struct tty_struct *tty, struct serial_struct v; int flags; - if (copy_from_user(&v32, ss, sizeof(struct serial_struct32))) + if (copy_from_user(&v32, ss, sizeof(*ss))) return -EFAULT; memcpy(&v, &v32, offsetof(struct serial_struct32, iomem_base)); @@ -2743,7 +2743,7 @@ static int compat_tty_tiocgserial(struct tty_struct *tty, 0xfffffff : ptr_to_compat(v.iomem_base); v32.iomem_reg_shift = v.iomem_reg_shift; v32.port_high = v.port_high; - if (copy_to_user(ss, &v32, sizeof(struct serial_struct32))) + if (copy_to_user(ss, &v32, sizeof(v32))) err = -EFAULT; } return err; -- 2.27.0
