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[0/9] serial: Fix out-of-bounds accesses through DT aliases

Message ID 1519119624-1268-1-git-send-email-geert+renesas@glider.be
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Series serial: Fix out-of-bounds accesses through DT aliases | expand

Message

Geert Uytterhoeven Feb. 20, 2018, 9:40 a.m. UTC 
Hi all,

Serial drivers used on DT platforms use the "serialN" alias in DT to
obtain the serial port index for a specific port.  Drivers typically use
a fixed-size array for keeping track of all available serial ports.
However, several drivers do not perform any validation on the index
obtained from DT, which may lead to out-of-bounds accesses of these
fixed-size arrays.

While the DTB passed to the kernel might be considered trusted, some of
these out-of-bounds accesses can be triggered by a legitimate DTB:
  - In some drivers the size of the array is defined by a Kconfig
    symbol, so a user who doesn't need all serial ports may lower this
    value rightfully,
  - Tomorrow's new SoC may have more serial ports than the fixed-size
    array in today's driver can accommodate, which the user may forget
    to enlarge.

Hence this series fixes that by adding checks for out-of-range aliases,
logging an error message when triggered.

Tested on r8a7791/koelsch (sh-sci), all other drivers were
compile-tested only.

Thanks for your comments!

Geert Uytterhoeven (9):
  serial: arc_uart: Fix out-of-bounds access through DT alias
  serial: fsl_lpuart: Fix out-of-bounds access through DT alias
  serial: imx: Fix out-of-bounds access through DT alias
  serial: mxs-auart: Fix out-of-bounds access through DT alias
  serial: pxa: Fix out-of-bounds access through DT alias
  serial: samsung: Fix out-of-bounds access through DT alias
  serial: sh-sci: Fix out-of-bounds access through DT alias
  serial: sirf: Fix out-of-bounds access through DT alias
  serial: xuartps: Fix out-of-bounds access through DT alias

 drivers/tty/serial/arc_uart.c      | 5 +++++
 drivers/tty/serial/fsl_lpuart.c    | 4 ++++
 drivers/tty/serial/imx.c           | 5 +++++
 drivers/tty/serial/mxs-auart.c     | 4 ++++
 drivers/tty/serial/pxa.c           | 4 ++++
 drivers/tty/serial/samsung.c       | 4 ++++
 drivers/tty/serial/sh-sci.c        | 4 ++++
 drivers/tty/serial/sirfsoc_uart.c  | 5 +++++
 drivers/tty/serial/xilinx_uartps.c | 2 +-
 9 files changed, 36 insertions(+), 1 deletion(-)