On Thu, Sep 8, 2016 at 8:05 PM, Geert Uytterhoeven
<geert+renesas@xxxxxxxxx> wrote:
> Sometimes spidev_test crashes with:
>
> *** Error in `spidev_test': munmap_chunk(): invalid pointer: 0x00022020 ***
> Aborted
>
> or just
>
> Segmentation fault
>
> This is due to transfer_escaped_string() miscalculating the required
> size of the buffer by two bytes, causing a buffer overflow in unescape().
>
> Move the misplaced closing parenthesis to fix this.
After one more night of sleep, I realized it's an off-by-one, not off-by-two
bug (unescape() doesn't copy the zero-terminator of the source string).
Will send v2 in a moment...
> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> Fixes: 30061915be6e3a2c ("spi: spidev_test: Added input buffer from the terminal")
> Cc: <stable@xxxxxxxxxxxxxxx> # v4.5+
> ---
> The bug is present in all kernels since v4.1, but in v4.5 the code was
> changed, and the source file was moved.
>
> The fix for older kernels is straight-forward, there's only a single
> strlen() call in Documentation/spi/spidev_test.c:
>
> - size = strlen(input_tx+1);
> + size = strlen(input_tx)+1;
>
> If you want, I can send a patch against v4.4 (for v4.1..v4.4) later.
> ---
> tools/spi/spidev_test.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/spi/spidev_test.c b/tools/spi/spidev_test.c
> index 1eaa4de6605bd935..ffa9908f7eb6670e 100644
> --- a/tools/spi/spidev_test.c
> +++ b/tools/spi/spidev_test.c
> @@ -285,7 +285,7 @@ static void parse_opts(int argc, char *argv[])
>
> static void transfer_escaped_string(int fd, char *str)
> {
> - size_t size = strlen(str + 1);
> + size_t size = strlen(str) + 1;
> uint8_t *tx;
> uint8_t *rx;
>
> --
> 1.9.1
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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