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author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-09 17:10:41 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-09 17:10:41 -0700 |
commit | 77e40aae766ccbbbb0324cb92ab22e6e998375d7 (patch) | |
tree | fb4e8e840aaeeaac62249d7585249c4634886baa /include/linux/nsproxy.h | |
parent | 96784de59fb35077c2bb33c39328992b836d87d3 (diff) | |
parent | 344470cac42e887e68cfb5bdfa6171baf27f1eb5 (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/linux/nsproxy.h')
-rw-r--r-- | include/linux/nsproxy.h | 16 |
1 files changed, 6 insertions, 10 deletions
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); |