From: Michal Suchanek msuchanek@suse.de
[ Upstream commit 358fcf5ddbec4e6706405847d6a666f5933a6c25 ]
When the kernel is locked down the kernel allows reading only debugfs files with mode 444. Mode 400 is also valid but is not allowed.
Make the 444 into a mask.
Fixes: 5496197f9b08 ("debugfs: Restrict debugfs when the kernel is locked down") Signed-off-by: Michal Suchanek msuchanek@suse.de Link: https://lore.kernel.org/r/20220104170505.10248-1-msuchanek@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/debugfs/file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c index a32c5c7dcfd89..da87615ad69a7 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -146,7 +146,7 @@ static int debugfs_locked_down(struct inode *inode, struct file *filp, const struct file_operations *real_fops) { - if ((inode->i_mode & 07777) == 0444 && + if ((inode->i_mode & 07777 & ~0444) == 0 && !(filp->f_mode & FMODE_WRITE) && !real_fops->unlocked_ioctl && !real_fops->compat_ioctl &&