[PATCH] dmaengine: qcom: hidma: avoid world-writable channel sysfs files

[PATCH] dmaengine: qcom: hidma: avoid world-writable channel sysfs files

[Hungyu Lin]

hidma_mgmt_init_sys() creates the per-channel priority and weight
attributes with S_IRUGO | S_IWUGO, so any local user can write them.
A write stores the new value and calls hidma_mgmt_setup(), which
programs it into the channel's QoS register.

Attributes declared with __ATTR() are checked at build time by
VERIFY_OCTAL_PERMISSIONS(), which rejects world-writable modes. These
two are created at runtime with a mode passed to
create_sysfs_entry_channel(), so the check does not reach them.

Make them writable by the owner only, the 0644 that __ATTR_RW() uses.

Fixes: 7f8f209fd6e0 ("dmaengine: add Qualcomm Technologies HIDMA management driver")
Cc: stable@vger.kernel.org
Signed-off-by: Hungyu Lin <dennylin0707@gmail.com>
---
 drivers/dma/qcom/hidma_mgmt_sys.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/qcom/hidma_mgmt_sys.c b/drivers/dma/qcom/hidma_mgmt_sys.c
index 9672ef9ee8fc..53b991752e80 100644
--- a/drivers/dma/qcom/hidma_mgmt_sys.c
+++ b/drivers/dma/qcom/hidma_mgmt_sys.c
@@ -265,13 +265,13 @@ int hidma_mgmt_init_sys(struct hidma_mgmt_dev *mdev)
 	/* populate parameters that are per channel */
 	for (i = 0; i < mdev->dma_channels; i++) {
 		rc = create_sysfs_entry_channel(mdev, "priority",
-						(S_IRUGO | S_IWUGO), i,
+						0644, i,
 						mdev->chroots[i]);
 		if (rc)
 			return rc;
 
 		rc = create_sysfs_entry_channel(mdev, "weight",
-						(S_IRUGO | S_IWUGO), i,
+						0644, i,
 						mdev->chroots[i]);
 		if (rc)
 			return rc;
-- 
2.43.0