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Message-Id: <20250501063240.25295-1-markus.burri@mt.com>
Date: Thu, 1 May 2025 08:32:40 +0200
From: Markus Burri <markus.burri@...com>
To: linux-kernel@...r.kernel.org
Cc: Markus Burri <markus.burri@...com>,
Nuno Sa <nuno.sa@...log.com>,
Olivier Moysan <olivier.moysan@...s.st.com>,
Jonathan Cameron <jic23@...nel.org>,
Lars-Peter Clausen <lars@...afoo.de>,
linux-iio@...r.kernel.org,
Markus Burri <markus.burri@....ch>
Subject: [PATCH v1] iio: backend: fix out-of-bound write
The buffer is set to 80 character. If a caller write more characters,
count is truncated to the max available space in "simple_write_to_buffer".
But afterwards a string terminator is written to the buffer at offset count
without boundary check. The zero termination is written OUT-OF-BOUND.
Add a check that the given buffer is smaller then the buffer to prevent.
Fixes: 035b4989211d ("iio: backend: make sure to NULL terminate stack buffer")
Signed-off-by: Markus Burri <markus.burri@...com>
---
drivers/iio/industrialio-backend.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/iio/industrialio-backend.c b/drivers/iio/industrialio-backend.c
index a43c8d1bb3d0..3878bd698c98 100644
--- a/drivers/iio/industrialio-backend.c
+++ b/drivers/iio/industrialio-backend.c
@@ -155,6 +155,9 @@ static ssize_t iio_backend_debugfs_write_reg(struct file *file,
ssize_t rc;
int ret;
+ if (count >= sizeof(buf))
+ return -ENOSPC;
+
rc = simple_write_to_buffer(buf, sizeof(buf) - 1, ppos, userbuf, count);
if (rc < 0)
return rc;
base-commit: b4432656b36e5cc1d50a1f2dc15357543add530e
--
2.39.5
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