[REVIEW][PATCH 6/6] fs: Allow CAP_SYS_ADMIN in s_user_ns to freeze and thaw filesystems

Eric W. Biederman
2018-05-23T23:27:25Z

From: Seth Forshee <seth.forshee@canonical.com>

The user in control of a super block should be allowed to freeze
and thaw it. Relax the restrictions on the FIFREEZE and FITHAW
ioctls to require CAP_SYS_ADMIN in s_user_ns.

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
fs/ioctl.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/ioctl.c b/fs/ioctl.c
index 4823431d1c9d..b445b13fc59b 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -549,7 +549,7 @@ static int ioctl_fsfreeze(struct file *filp)
{
struct super_block *sb = file_inode(filp)->i_sb;

- if (!capable(CAP_SYS_ADMIN))
+ if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN))
return -EPERM;

/* If filesystem doesn't support freeze feature, return. */
@@ -566,7 +566,7 @@ static int ioctl_fsthaw(struct file *filp)
{
struct super_block *sb = file_inode(filp)->i_sb;

- if (!capable(CAP_SYS_ADMIN))
+ if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN))
return -EPERM;

/* Thaw */
--
2.14.1