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Message-Id: <20250508130612.82270-5-markus.burri@mt.com>
Date: Thu, 8 May 2025 15:06:10 +0200
From: Markus Burri <markus.burri@...com>
To: linux-kernel@...r.kernel.org
Cc: Markus Burri <markus.burri@...com>,
Mahesh J Salgaonkar <mahesh@...ux.ibm.com>,
"Oliver O'Halloran" <oohall@...il.com>,
Madhavan Srinivasan <maddy@...ux.ibm.com>,
Michael Ellerman <mpe@...erman.id.au>,
Nicholas Piggin <npiggin@...il.com>,
Christophe Leroy <christophe.leroy@...roup.eu>,
Naveen N Rao <naveen@...nel.org>,
Jacek Lawrynowicz <jacek.lawrynowicz@...ux.intel.com>,
Maciej Falkowski <maciej.falkowski@...ux.intel.com>,
Oded Gabbay <ogabbay@...nel.org>,
Linus Walleij <linus.walleij@...aro.org>,
Bartosz Golaszewski <brgl@...ev.pl>,
Nuno Sa <nuno.sa@...log.com>,
Olivier Moysan <olivier.moysan@...s.st.com>,
Jonathan Cameron <jic23@...nel.org>,
Lars-Peter Clausen <lars@...afoo.de>,
linuxppc-dev@...ts.ozlabs.org,
dri-devel@...ts.freedesktop.org,
linux-gpio@...r.kernel.org,
linux-iio@...r.kernel.org,
Markus Burri <markus.burri@....ch>
Subject: [PATCH v4 4/6] gpio: fix potential out-of-bound write
Check that the input size does not exceed the buffer size.
If a caller write more characters, count is truncated to the max available
space in "simple_write_to_buffer".
Write a zero termination afterwards.
Signed-off-by: Markus Burri <markus.burri@...com>
---
drivers/gpio/gpio-virtuser.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/gpio/gpio-virtuser.c b/drivers/gpio/gpio-virtuser.c
index 13407fd4f0eb..9f3c491f5af1 100644
--- a/drivers/gpio/gpio-virtuser.c
+++ b/drivers/gpio/gpio-virtuser.c
@@ -401,10 +401,15 @@ 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 (size >= 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) {
@@ -623,12 +628,15 @@ 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)
--
2.39.5
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