History

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

Linus Torvalds committed 12 years ago

Commit 77e40aa2 parents 96784de 344470c23 files · +537 −97Browse files

Showing the changes to include/linux (3 of 23 files). Show all

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3 files
  1. include/linux/mount.h +8 −1
  2. include/linux/nsproxy.h +6 −10
  3. include/linux/pid_namespace.h +1 −0
include/linux/mount.h+8−1
@@ -42,13 +42,20 @@ struct mnt_namespace; · 41 unmodified lines
42 * flag, consider how it interacts with shared mounts.42 * flag, consider how it interacts with shared mounts.
43 */43 */
44#define MNT_SHARED_MASK (MNT_UNBINDABLE)44#define MNT_SHARED_MASK (MNT_UNBINDABLE)
45#define MNT_PROPAGATION_MASK (MNT_SHARED | MNT_UNBINDABLE)45#define MNT_USER_SETTABLE_MASK (MNT_NOSUID | MNT_NODEV | MNT_NOEXEC \
46 | MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME \
47 | MNT_READONLY)
48#define MNT_ATIME_MASK (MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME )
46 49
47#define MNT_INTERNAL_FLAGS (MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL | \50#define MNT_INTERNAL_FLAGS (MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL | \
48 MNT_DOOMED | MNT_SYNC_UMOUNT | MNT_MARKED)51 MNT_DOOMED | MNT_SYNC_UMOUNT | MNT_MARKED)
49 52
50#define MNT_INTERNAL 0x400053#define MNT_INTERNAL 0x4000
51 54
55#define MNT_LOCK_ATIME 0x040000
56#define MNT_LOCK_NOEXEC 0x080000
57#define MNT_LOCK_NOSUID 0x100000
58#define MNT_LOCK_NODEV 0x200000
52#define MNT_LOCK_READONLY 0x40000059#define MNT_LOCK_READONLY 0x400000
53#define MNT_LOCKED 0x80000060#define MNT_LOCKED 0x800000
54#define MNT_DOOMED 0x100000061#define MNT_DOOMED 0x1000000
include/linux/nsproxy.h+6−10
@@ -40,32 +40,28 @@ extern struct nsproxy init_nsproxy; · 39 unmodified lines
40 * the namespaces access rules are:40 * the namespaces access rules are:
41 *41 *
42 * 1. only current task is allowed to change tsk->nsproxy pointer or42 * 1. only current task is allowed to change tsk->nsproxy pointer or
43 * any pointer on the nsproxy itself43 * any pointer on the nsproxy itself. Current must hold the task_lock
44 * when changing tsk->nsproxy.
44 *45 *
45 * 2. when accessing (i.e. reading) current task's namespaces - no46 * 2. when accessing (i.e. reading) current task's namespaces - no
46 * precautions should be taken - just dereference the pointers47 * precautions should be taken - just dereference the pointers
47 *48 *
48 * 3. the access to other task namespaces is performed like this49 * 3. the access to other task namespaces is performed like this
49 * rcu_read_lock();50 * task_lock(task);
50 * nsproxy = task_nsproxy(tsk);51 * nsproxy = task->nsproxy;
51 * if (nsproxy != NULL) {52 * if (nsproxy != NULL) {
52 * / *53 * / *
53 * * work with the namespaces here54 * * work with the namespaces here
54 * * e.g. get the reference on one of them55 * * e.g. get the reference on one of them
55 * * /56 * * /
56 * } / *57 * } / *
57 * * NULL task_nsproxy() means that this task is58 * * NULL task->nsproxy means that this task is
58 * * almost dead (zombie)59 * * almost dead (zombie)
59 * * /60 * * /
60 * rcu_read_unlock();61 * task_unlock(task);
61 *62 *
62 */63 */
63 64
64static inline struct nsproxy *task_nsproxy(struct task_struct *tsk)
65{
66 return rcu_dereference(tsk->nsproxy);
67}
68
69int copy_namespaces(unsigned long flags, struct task_struct *tsk);65int copy_namespaces(unsigned long flags, struct task_struct *tsk);
70void exit_task_namespaces(struct task_struct *tsk);66void exit_task_namespaces(struct task_struct *tsk);
71void switch_task_namespaces(struct task_struct *tsk, struct nsproxy *new);67void switch_task_namespaces(struct task_struct *tsk, struct nsproxy *new);
include/linux/pid_namespace.h+1−0
@@ -33,6 +33,7 @@ struct pid_namespace { · 32 unmodified lines
33#ifdef CONFIG_PROC_FS33#ifdef CONFIG_PROC_FS
34 struct vfsmount *proc_mnt;34 struct vfsmount *proc_mnt;
35 struct dentry *proc_self;35 struct dentry *proc_self;
36 struct dentry *proc_thread_self;
36#endif37#endif
37#ifdef CONFIG_BSD_PROCESS_ACCT38#ifdef CONFIG_BSD_PROCESS_ACCT
38 struct bsd_acct_struct *bacct;39 struct bsd_acct_struct *bacct;