[PATCH 5.14 190/849] iio: buffer: check return value of kstrdup_const()

Greg Kroah-Hartman
2021-11-16T01:42:43Z

From: Yang Yingliang <yangyingliang@huawei.com>

commit 2c0ad3f0cc04dec489552a21b80cd6d708bea96d upstream.

Check return value of kstrdup_const() in iio_buffer_wrap_attr(),
or it will cause null-ptr-deref in kernfs_name_hash() when calling
device_add() as follows:

BUG: kernel NULL pointer dereference, address: 0000000000000000
RIP: 0010:strlen+0x0/0x20
Call Trace:
kernfs_name_hash+0x22/0x110
kernfs_find_ns+0x11d/0x390
kernfs_remove_by_name_ns+0x3b/0xb0
remove_files.isra.1+0x7b/0x190
internal_create_group+0x7f1/0xbb0
internal_create_groups+0xa3/0x150
device_add+0x8f0/0x2020
cdev_device_add+0xc3/0x160
__iio_device_register+0x1427/0x1b40 [industrialio]
__devm_iio_device_register+0x22/0x80 [industrialio]
adjd_s311_probe+0x195/0x200 [adjd_s311]
i2c_device_probe+0xa07/0xbb0

Reported-by: Hulk Robot <hulkci@huawei.com>
Fixes: 15097c7a1adc ("iio: buffer: wrap all buffer attributes into iio_dev_attr")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20211013040438.1689277-1-yangyingliang@huawei.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/iio/industrialio-buffer.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -1311,6 +1311,11 @@ static struct attribute *iio_buffer_wrap
iio_attr->buffer = buffer;
memcpy(&iio_attr->dev_attr, dattr, sizeof(iio_attr->dev_attr));
iio_attr->dev_attr.attr.name = kstrdup_const(attr->name, GFP_KERNEL);
+ if (!iio_attr->dev_attr.attr.name) {
+ kfree(iio_attr);
+ return NULL;
+ }
+
sysfs_attr_init(&iio_attr->dev_attr.attr);

list_add(&iio_attr->l, &buffer->buffer_attr_list);