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authorEric W. Biederman <ebiederm@xmission.com>2013-03-22 04:08:05 -0700
committerEric W. Biederman <ebiederm@xmission.com>2013-03-27 07:50:05 -0700
commit132c94e31b8bca8ea921f9f96a57d684fa4ae0a9 (patch)
tree52db12073a31f62301367416b2a3afec185975ef /fs/pnode.h
parent90563b198e4c6674c63672fae1923da467215f45 (diff)
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vfs: Carefully propogate mounts across user namespaces
As a matter of policy MNT_READONLY should not be changable if the original mounter had more privileges than creator of the mount namespace. Add the flag CL_UNPRIVILEGED to note when we are copying a mount from a mount namespace that requires more privileges to a mount namespace that requires fewer privileges. When the CL_UNPRIVILEGED flag is set cause clone_mnt to set MNT_NO_REMOUNT if any of the mnt flags that should never be changed are set. This protects both mount propagation and the initial creation of a less privileged mount namespace. Cc: stable@vger.kernel.org Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Reported-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'fs/pnode.h')
-rw-r--r--fs/pnode.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/pnode.h b/fs/pnode.h
index 19b853a3445c..a0493d5ebfbf 100644
--- a/fs/pnode.h
+++ b/fs/pnode.h
@@ -23,6 +23,7 @@
#define CL_MAKE_SHARED 0x08
#define CL_PRIVATE 0x10
#define CL_SHARED_TO_SLAVE 0x20
+#define CL_UNPRIVILEGED 0x40
static inline void set_mnt_shared(struct mount *mnt)
{