Re: [PATCH -next] iio: buffer: Check the return value of kstrdup_const()
From: Jonathan Cameron <jic23@kernel.org>
Date: 2021-10-17 13:44:54
Also in:
lkml
On Mon, 11 Oct 2021 12:58:46 +0000 Wang Wensheng [off-list ref] wrote:
We should check the duplication of attr.name properly in
iio_buffer_wrap_attr() or a null-pointer-dereference would
occur on destroying the related sysfs file.
This issue is found by fault-injection.
BUG: kernel NULL pointer dereference, address: 0000000000000000
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI
RIP: 0010:strlen+0x0/0x20
Call Trace:
kernfs_name_hash+0x1c/0xb0
kernfs_find_ns+0xc6/0x160
kernfs_remove_by_name_ns+0x5c/0xb0
remove_files.isra.1+0x42/0x90
internal_create_group+0x42f/0x460
internal_create_groups+0x49/0xc0
device_add+0xb5b/0xbe0
? kobject_get+0x90/0xa0
cdev_device_add+0x2b/0x90
__iio_device_register+0xa56/0xb40
Fixes: 15097c7a1adc ("iio: buffer: wrap all buffer attributes into iio_dev_attr")
Reported-by: Hulk Robot<redacted>
Signed-off-by: Wang Wensheng <redacted>This version seems to be a duplicate with the version Yang Yingliang sent a few days later, but that version has the free of the iio_attr which is missing here. Thanks, Jonathan
quoted hunk ↗ jump to hunk
--- drivers/iio/industrialio-buffer.c | 2 ++ 1 file changed, 2 insertions(+)diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c index c648e9553edd..f4011c477bac 100644 --- a/drivers/iio/industrialio-buffer.c +++ b/drivers/iio/industrialio-buffer.c@@ -1312,6 +1312,8 @@ static struct attribute *iio_buffer_wrap_attr(struct iio_buffer *buffer, 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) + return NULL; sysfs_attr_init(&iio_attr->dev_attr.attr); list_add(&iio_attr->l, &buffer->buffer_attr_list);