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    Subject[PATCH AUTOSEL 4.9 57/90] tools: gpio-hammer: Avoid potential overflow in main
    Date
    From: Gabriel Ravier <gabravier@gmail.com>

    [ Upstream commit d1ee7e1f5c9191afb69ce46cc7752e4257340a31 ]

    If '-o' was used more than 64 times in a single invocation of gpio-hammer,
    this could lead to an overflow of the 'lines' array. This commit fixes
    this by avoiding the overflow and giving a proper diagnostic back to the
    user

    Signed-off-by: Gabriel Ravier <gabravier@gmail.com>
    Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    tools/gpio/gpio-hammer.c | 17 ++++++++++++++++-
    1 file changed, 16 insertions(+), 1 deletion(-)

    diff --git a/tools/gpio/gpio-hammer.c b/tools/gpio/gpio-hammer.c
    index 37b3f141053df..85f45800f881f 100644
    --- a/tools/gpio/gpio-hammer.c
    +++ b/tools/gpio/gpio-hammer.c
    @@ -171,7 +171,14 @@ int main(int argc, char **argv)
    device_name = optarg;
    break;
    case 'o':
    - lines[i] = strtoul(optarg, NULL, 10);
    + /*
    + * Avoid overflow. Do not immediately error, we want to
    + * be able to accurately report on the amount of times
    + * '-o' was given to give an accurate error message
    + */
    + if (i < GPIOHANDLES_MAX)
    + lines[i] = strtoul(optarg, NULL, 10);
    +
    i++;
    break;
    case '?':
    @@ -179,6 +186,14 @@ int main(int argc, char **argv)
    return -1;
    }
    }
    +
    + if (i >= GPIOHANDLES_MAX) {
    + fprintf(stderr,
    + "Only %d occurences of '-o' are allowed, %d were found\n",
    + GPIOHANDLES_MAX, i + 1);
    + return -1;
    + }
    +
    nlines = i;

    if (!device_name || !nlines) {
    --
    2.25.1
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