On Thu, 8 May 2025 15:06:09 +0200
Markus Burri [off-list ref] wrote:
The buffer is set to 20 characters. If a caller write more characters,
count is truncated to the max available space in "simple_write_to_buffer".
To protect from OoB access, check that the input size fit into buffer and
add a zero terminator after copy to the end of the copied data.
Signed-off-by: Markus Burri <redacted>
I added
Fixes: 6d5dd486c715 ("iio: core: make use of simple_write_to_buffer()")
If it predates that we'll need a manual backport anyway. If you have time to
take a look at that Markus that would be great.
Jonathan
quoted hunk ↗ jump to hunk
---
drivers/iio/industrialio-core.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index b9f4113ae5fc..ebf17ea5a5f9 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -410,12 +410,15 @@ static ssize_t iio_debugfs_write_reg(struct file *file,
char buf[80];
int ret;
+ if (count >= sizeof(buf))
+ return -EINVAL;
+
ret = simple_write_to_buffer(buf, sizeof(buf) - 1, ppos, userbuf,
count);
if (ret < 0)
return ret;
- buf[count] = '\0';
+ buf[ret] = '\0';
ret = sscanf(buf, "%i %i", ®, &val);