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authorLinus Torvalds <torvalds@linux-foundation.org>2014-08-09 17:10:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-08-09 17:10:41 -0700
commit77e40aae766ccbbbb0324cb92ab22e6e998375d7 (patch)
treefb4e8e840aaeeaac62249d7585249c4634886baa /include
parent96784de59fb35077c2bb33c39328992b836d87d3 (diff)
parent344470cac42e887e68cfb5bdfa6171baf27f1eb5 (diff)
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull namespace updates from Eric Biederman: "This is a bunch of small changes built against 3.16-rc6. The most significant change for users is the first patch which makes setns drmatically faster by removing unneded rcu handling. The next chunk of changes are so that "mount -o remount,.." will not allow the user namespace root to drop flags on a mount set by the system wide root. Aks this forces read-only mounts to stay read-only, no-dev mounts to stay no-dev, no-suid mounts to stay no-suid, no-exec mounts to stay no exec and it prevents unprivileged users from messing with a mounts atime settings. I have included my test case as the last patch in this series so people performing backports can verify this change works correctly. The next change fixes a bug in NFS that was discovered while auditing nsproxy users for the first optimization. Today you can oops the kernel by reading /proc/fs/nfsfs/{servers,volumes} if you are clever with pid namespaces. I rebased and fixed the build of the !CONFIG_NFS_FS case yesterday when a build bot caught my typo. Given that no one to my knowledge bases anything on my tree fixing the typo in place seems more responsible that requiring a typo-fix to be backported as well. The last change is a small semantic cleanup introducing /proc/thread-self and pointing /proc/mounts and /proc/net at it. This prevents several kinds of problemantic corner cases. It is a user-visible change so it has a minute chance of causing regressions so the change to /proc/mounts and /proc/net are individual one line commits that can be trivially reverted. Unfortunately I lost and could not find the email of the original reporter so he is not credited. From at least one perspective this change to /proc/net is a refgression fix to allow pthread /proc/net uses that were broken by the introduction of the network namespace" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: proc: Point /proc/mounts at /proc/thread-self/mounts instead of /proc/self/mounts proc: Point /proc/net at /proc/thread-self/net instead of /proc/self/net proc: Implement /proc/thread-self to point at the directory of the current thread proc: Have net show up under /proc/<tgid>/task/<tid> NFS: Fix /proc/fs/nfsfs/servers and /proc/fs/nfsfs/volumes mnt: Add tests for unprivileged remount cases that have found to be faulty mnt: Change the default remount atime from relatime to the existing value mnt: Correct permission checks in do_remount mnt: Move the test for MNT_LOCK_READONLY from change_mount_flags into do_remount mnt: Only change user settable mount flags in remount namespaces: Use task_lock and not rcu to protect nsproxy
Diffstat (limited to 'include')
-rw-r--r--include/linux/mount.h9
-rw-r--r--include/linux/nsproxy.h16
-rw-r--r--include/linux/pid_namespace.h1
3 files changed, 15 insertions, 11 deletions
diff --git a/include/linux/mount.h b/include/linux/mount.h
index 839bac270904..b0c1e6574e7f 100644
--- a/include/linux/mount.h
+++ b/include/linux/mount.h
@@ -42,13 +42,20 @@ struct mnt_namespace;
* flag, consider how it interacts with shared mounts.
*/
#define MNT_SHARED_MASK (MNT_UNBINDABLE)
-#define MNT_PROPAGATION_MASK (MNT_SHARED | MNT_UNBINDABLE)
+#define MNT_USER_SETTABLE_MASK (MNT_NOSUID | MNT_NODEV | MNT_NOEXEC \
+ | MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME \
+ | MNT_READONLY)
+#define MNT_ATIME_MASK (MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME )
#define MNT_INTERNAL_FLAGS (MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL | \
MNT_DOOMED | MNT_SYNC_UMOUNT | MNT_MARKED)
#define MNT_INTERNAL 0x4000
+#define MNT_LOCK_ATIME 0x040000
+#define MNT_LOCK_NOEXEC 0x080000
+#define MNT_LOCK_NOSUID 0x100000
+#define MNT_LOCK_NODEV 0x200000
#define MNT_LOCK_READONLY 0x400000
#define MNT_LOCKED 0x800000
#define MNT_DOOMED 0x1000000
diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
index b4ec59d159ac..35fa08fd7739 100644
--- a/include/linux/nsproxy.h
+++ b/include/linux/nsproxy.h
@@ -40,32 +40,28 @@ extern struct nsproxy init_nsproxy;
* the namespaces access rules are:
*
* 1. only current task is allowed to change tsk->nsproxy pointer or
- * any pointer on the nsproxy itself
+ * any pointer on the nsproxy itself. Current must hold the task_lock
+ * when changing tsk->nsproxy.
*
* 2. when accessing (i.e. reading) current task's namespaces - no
* precautions should be taken - just dereference the pointers
*
* 3. the access to other task namespaces is performed like this
- * rcu_read_lock();
- * nsproxy = task_nsproxy(tsk);
+ * task_lock(task);
+ * nsproxy = task->nsproxy;
* if (nsproxy != NULL) {
* / *
* * work with the namespaces here
* * e.g. get the reference on one of them
* * /
* } / *
- * * NULL task_nsproxy() means that this task is
+ * * NULL task->nsproxy means that this task is
* * almost dead (zombie)
* * /
- * rcu_read_unlock();
+ * task_unlock(task);
*
*/
-static inline struct nsproxy *task_nsproxy(struct task_struct *tsk)
-{
- return rcu_dereference(tsk->nsproxy);
-}
-
int copy_namespaces(unsigned long flags, struct task_struct *tsk);
void exit_task_namespaces(struct task_struct *tsk);
void switch_task_namespaces(struct task_struct *tsk, struct nsproxy *new);
diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index 7246ef3d4455..1997ffc295a7 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -33,6 +33,7 @@ struct pid_namespace {
#ifdef CONFIG_PROC_FS
struct vfsmount *proc_mnt;
struct dentry *proc_self;
+ struct dentry *proc_thread_self;
#endif
#ifdef CONFIG_BSD_PROCESS_ACCT
struct bsd_acct_struct *bacct;