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.
Changes compared to v1:
- Fix Fixes references,
- Use ARRAY_SIZE(),
- Fix off-by-one error in patch [5/9],
- Document where the non-DT case is also fixed by a patch.
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 serial port index
serial: mxs-auart: Fix out-of-bounds access through serial port index
serial: pxa: Fix out-of-bounds access through serial port index
serial: samsung: Fix out-of-bounds access through serial port index
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 | 6 ++++++
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, 37 insertions(+), 1 deletion(-)
--
2.7.4
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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