From: Markus Burri Date: Fri, 9 May 2025 15:04:59 +0000 (+0200) Subject: gpio: virtuser: fix potential out-of-bound write X-Git-Tag: v6.14.10~18 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b96feaaa0fda1e3871b438143c3446954b32d3a7;p=thirdparty%2Fkernel%2Fstable.git gpio: virtuser: fix potential out-of-bound write [ Upstream commit 7118be7c6072f40391923543fdd1563b8d56377c ] If the caller wrote more characters, count is truncated to the max available space in "simple_write_to_buffer". Check that the input size does not exceed the buffer size. Write a zero termination afterwards. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202505091754.285hHbr2-lkp@intel.com/ Signed-off-by: Markus Burri Link: https://lore.kernel.org/r/20250509150459.115489-1-markus.burri@mt.com Signed-off-by: Bartosz Golaszewski Signed-off-by: Sasha Levin --- diff --git a/drivers/gpio/gpio-virtuser.c b/drivers/gpio/gpio-virtuser.c index e89f299f21400..dcecb7a259117 100644 --- a/drivers/gpio/gpio-virtuser.c +++ b/drivers/gpio/gpio-virtuser.c @@ -400,10 +400,15 @@ static ssize_t gpio_virtuser_direction_do_write(struct file *file, char buf[32], *trimmed; int ret, dir, val = 0; - ret = simple_write_to_buffer(buf, sizeof(buf), ppos, user_buf, count); + if (count >= sizeof(buf)) + return -EINVAL; + + ret = simple_write_to_buffer(buf, sizeof(buf) - 1, ppos, user_buf, count); if (ret < 0) return ret; + buf[ret] = '\0'; + trimmed = strim(buf); if (strcmp(trimmed, "input") == 0) { @@ -622,12 +627,15 @@ static ssize_t gpio_virtuser_consumer_write(struct file *file, char buf[GPIO_VIRTUSER_NAME_BUF_LEN + 2]; int ret; + if (count >= sizeof(buf)) + return -EINVAL; + ret = simple_write_to_buffer(buf, GPIO_VIRTUSER_NAME_BUF_LEN, ppos, user_buf, count); if (ret < 0) return ret; - buf[strlen(buf) - 1] = '\0'; + buf[ret] = '\0'; ret = gpiod_set_consumer_name(data->ad.desc, buf); if (ret)