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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
parent96784de59fb35077c2bb33c39328992b836d87d3 (diff)
parent344470cac42e887e68cfb5bdfa6171baf27f1eb5 (diff)
downloadleg-kernel-77e40aae766ccbbbb0324cb92ab22e6e998375d7.tar.gz
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
-rw-r--r--fs/namespace.c65
-rw-r--r--fs/nfs/client.c95
-rw-r--r--fs/nfs/inode.c3
-rw-r--r--fs/nfs/internal.h9
-rw-r--r--fs/nfs/netns.h3
-rw-r--r--fs/proc/Makefile1
-rw-r--r--fs/proc/base.c18
-rw-r--r--fs/proc/inode.c7
-rw-r--r--fs/proc/internal.h6
-rw-r--r--fs/proc/proc_net.c6
-rw-r--r--fs/proc/root.c5
-rw-r--r--fs/proc/thread_self.c85
-rw-r--r--fs/proc_namespace.c8
-rw-r--r--include/linux/mount.h9
-rw-r--r--include/linux/nsproxy.h16
-rw-r--r--include/linux/pid_namespace.h1
-rw-r--r--ipc/namespace.c6
-rw-r--r--kernel/nsproxy.c15
-rw-r--r--kernel/utsname.c6
-rw-r--r--net/core/net_namespace.c10
-rw-r--r--tools/testing/selftests/Makefile1
-rw-r--r--tools/testing/selftests/mount/Makefile17
-rw-r--r--tools/testing/selftests/mount/unprivileged-remount-test.c242
23 files changed, 537 insertions, 97 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index 2a1447c946e7..0acabea58319 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -890,8 +890,21 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
mnt->mnt.mnt_flags = old->mnt.mnt_flags & ~(MNT_WRITE_HOLD|MNT_MARKED);
/* Don't allow unprivileged users to change mount flags */
- if ((flag & CL_UNPRIVILEGED) && (mnt->mnt.mnt_flags & MNT_READONLY))
- mnt->mnt.mnt_flags |= MNT_LOCK_READONLY;
+ if (flag & CL_UNPRIVILEGED) {
+ mnt->mnt.mnt_flags |= MNT_LOCK_ATIME;
+
+ if (mnt->mnt.mnt_flags & MNT_READONLY)
+ mnt->mnt.mnt_flags |= MNT_LOCK_READONLY;
+
+ if (mnt->mnt.mnt_flags & MNT_NODEV)
+ mnt->mnt.mnt_flags |= MNT_LOCK_NODEV;
+
+ if (mnt->mnt.mnt_flags & MNT_NOSUID)
+ mnt->mnt.mnt_flags |= MNT_LOCK_NOSUID;
+
+ if (mnt->mnt.mnt_flags & MNT_NOEXEC)
+ mnt->mnt.mnt_flags |= MNT_LOCK_NOEXEC;
+ }
/* Don't allow unprivileged users to reveal what is under a mount */
if ((flag & CL_UNPRIVILEGED) && list_empty(&old->mnt_expire))
@@ -1896,9 +1909,6 @@ static int change_mount_flags(struct vfsmount *mnt, int ms_flags)
if (readonly_request == __mnt_is_readonly(mnt))
return 0;
- if (mnt->mnt_flags & MNT_LOCK_READONLY)
- return -EPERM;
-
if (readonly_request)
error = mnt_make_readonly(real_mount(mnt));
else
@@ -1924,6 +1934,33 @@ static int do_remount(struct path *path, int flags, int mnt_flags,
if (path->dentry != path->mnt->mnt_root)
return -EINVAL;
+ /* Don't allow changing of locked mnt flags.
+ *
+ * No locks need to be held here while testing the various
+ * MNT_LOCK flags because those flags can never be cleared
+ * once they are set.
+ */
+ if ((mnt->mnt.mnt_flags & MNT_LOCK_READONLY) &&
+ !(mnt_flags & MNT_READONLY)) {
+ return -EPERM;
+ }
+ if ((mnt->mnt.mnt_flags & MNT_LOCK_NODEV) &&
+ !(mnt_flags & MNT_NODEV)) {
+ return -EPERM;
+ }
+ if ((mnt->mnt.mnt_flags & MNT_LOCK_NOSUID) &&
+ !(mnt_flags & MNT_NOSUID)) {
+ return -EPERM;
+ }
+ if ((mnt->mnt.mnt_flags & MNT_LOCK_NOEXEC) &&
+ !(mnt_flags & MNT_NOEXEC)) {
+ return -EPERM;
+ }
+ if ((mnt->mnt.mnt_flags & MNT_LOCK_ATIME) &&
+ ((mnt->mnt.mnt_flags & MNT_ATIME_MASK) != (mnt_flags & MNT_ATIME_MASK))) {
+ return -EPERM;
+ }
+
err = security_sb_remount(sb, data);
if (err)
return err;
@@ -1937,7 +1974,7 @@ static int do_remount(struct path *path, int flags, int mnt_flags,
err = do_remount_sb(sb, flags, data, 0);
if (!err) {
lock_mount_hash();
- mnt_flags |= mnt->mnt.mnt_flags & MNT_PROPAGATION_MASK;
+ mnt_flags |= mnt->mnt.mnt_flags & ~MNT_USER_SETTABLE_MASK;
mnt->mnt.mnt_flags = mnt_flags;
touch_mnt_namespace(mnt->mnt_ns);
unlock_mount_hash();
@@ -2122,7 +2159,7 @@ static int do_new_mount(struct path *path, const char *fstype, int flags,
*/
if (!(type->fs_flags & FS_USERNS_DEV_MOUNT)) {
flags |= MS_NODEV;
- mnt_flags |= MNT_NODEV;
+ mnt_flags |= MNT_NODEV | MNT_LOCK_NODEV;
}
}
@@ -2436,6 +2473,14 @@ long do_mount(const char *dev_name, const char *dir_name,
if (flags & MS_RDONLY)
mnt_flags |= MNT_READONLY;
+ /* The default atime for remount is preservation */
+ if ((flags & MS_REMOUNT) &&
+ ((flags & (MS_NOATIME | MS_NODIRATIME | MS_RELATIME |
+ MS_STRICTATIME)) == 0)) {
+ mnt_flags &= ~MNT_ATIME_MASK;
+ mnt_flags |= path.mnt->mnt_flags & MNT_ATIME_MASK;
+ }
+
flags &= ~(MS_NOSUID | MS_NOEXEC | MS_NODEV | MS_ACTIVE | MS_BORN |
MS_NOATIME | MS_NODIRATIME | MS_RELATIME| MS_KERNMOUNT |
MS_STRICTATIME);
@@ -2972,13 +3017,13 @@ static void *mntns_get(struct task_struct *task)
struct mnt_namespace *ns = NULL;
struct nsproxy *nsproxy;
- rcu_read_lock();
- nsproxy = task_nsproxy(task);
+ task_lock(task);
+ nsproxy = task->nsproxy;
if (nsproxy) {
ns = nsproxy->mnt_ns;
get_mnt_ns(ns);
}
- rcu_read_unlock();
+ task_unlock(task);
return ns;
}
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 1d09289c8f0e..180d1ec9c32e 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -1205,7 +1205,7 @@ static const struct file_operations nfs_server_list_fops = {
.open = nfs_server_list_open,
.read = seq_read,
.llseek = seq_lseek,
- .release = seq_release,
+ .release = seq_release_net,
.owner = THIS_MODULE,
};
@@ -1226,7 +1226,7 @@ static const struct file_operations nfs_volume_list_fops = {
.open = nfs_volume_list_open,
.read = seq_read,
.llseek = seq_lseek,
- .release = seq_release,
+ .release = seq_release_net,
.owner = THIS_MODULE,
};
@@ -1236,19 +1236,8 @@ static const struct file_operations nfs_volume_list_fops = {
*/
static int nfs_server_list_open(struct inode *inode, struct file *file)
{
- struct seq_file *m;
- int ret;
- struct pid_namespace *pid_ns = file->f_dentry->d_sb->s_fs_info;
- struct net *net = pid_ns->child_reaper->nsproxy->net_ns;
-
- ret = seq_open(file, &nfs_server_list_ops);
- if (ret < 0)
- return ret;
-
- m = file->private_data;
- m->private = net;
-
- return 0;
+ return seq_open_net(inode, file, &nfs_server_list_ops,
+ sizeof(struct seq_net_private));
}
/*
@@ -1256,7 +1245,7 @@ static int nfs_server_list_open(struct inode *inode, struct file *file)
*/
static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos)
{
- struct nfs_net *nn = net_generic(m->private, nfs_net_id);
+ struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
/* lock the list against modification */
spin_lock(&nn->nfs_client_lock);
@@ -1268,7 +1257,7 @@ static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos)
*/
static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos)
{
- struct nfs_net *nn = net_generic(p->private, nfs_net_id);
+ struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
return seq_list_next(v, &nn->nfs_client_list, pos);
}
@@ -1278,7 +1267,7 @@ static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos)
*/
static void nfs_server_list_stop(struct seq_file *p, void *v)
{
- struct nfs_net *nn = net_generic(p->private, nfs_net_id);
+ struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
spin_unlock(&nn->nfs_client_lock);
}
@@ -1289,7 +1278,7 @@ static void nfs_server_list_stop(struct seq_file *p, void *v)
static int nfs_server_list_show(struct seq_file *m, void *v)
{
struct nfs_client *clp;
- struct nfs_net *nn = net_generic(m->private, nfs_net_id);
+ struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
/* display header on line 1 */
if (v == &nn->nfs_client_list) {
@@ -1321,19 +1310,8 @@ static int nfs_server_list_show(struct seq_file *m, void *v)
*/
static int nfs_volume_list_open(struct inode *inode, struct file *file)
{
- struct seq_file *m;
- int ret;
- struct pid_namespace *pid_ns = file->f_dentry->d_sb->s_fs_info;
- struct net *net = pid_ns->child_reaper->nsproxy->net_ns;
-
- ret = seq_open(file, &nfs_volume_list_ops);
- if (ret < 0)
- return ret;
-
- m = file->private_data;
- m->private = net;
-
- return 0;
+ return seq_open_net(inode, file, &nfs_server_list_ops,
+ sizeof(struct seq_net_private));
}
/*
@@ -1341,7 +1319,7 @@ static int nfs_volume_list_open(struct inode *inode, struct file *file)
*/
static void *nfs_volume_list_start(struct seq_file *m, loff_t *_pos)
{
- struct nfs_net *nn = net_generic(m->private, nfs_net_id);
+ struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
/* lock the list against modification */
spin_lock(&nn->nfs_client_lock);
@@ -1353,7 +1331,7 @@ static void *nfs_volume_list_start(struct seq_file *m, loff_t *_pos)
*/
static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos)
{
- struct nfs_net *nn = net_generic(p->private, nfs_net_id);
+ struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
return seq_list_next(v, &nn->nfs_volume_list, pos);
}
@@ -1363,7 +1341,7 @@ static void *nfs_volume_list_next(struct seq_file *p, void *v, loff_t *pos)
*/
static void nfs_volume_list_stop(struct seq_file *p, void *v)
{
- struct nfs_net *nn = net_generic(p->private, nfs_net_id);
+ struct nfs_net *nn = net_generic(seq_file_net(p), nfs_net_id);
spin_unlock(&nn->nfs_client_lock);
}
@@ -1376,7 +1354,7 @@ static int nfs_volume_list_show(struct seq_file *m, void *v)
struct nfs_server *server;
struct nfs_client *clp;
char dev[8], fsid[17];
- struct nfs_net *nn = net_generic(m->private, nfs_net_id);
+ struct nfs_net *nn = net_generic(seq_file_net(m), nfs_net_id);
/* display header on line 1 */
if (v == &nn->nfs_volume_list) {
@@ -1407,6 +1385,45 @@ static int nfs_volume_list_show(struct seq_file *m, void *v)
return 0;
}
+int nfs_fs_proc_net_init(struct net *net)
+{
+ struct nfs_net *nn = net_generic(net, nfs_net_id);
+ struct proc_dir_entry *p;
+
+ nn->proc_nfsfs = proc_net_mkdir(net, "nfsfs", net->proc_net);
+ if (!nn->proc_nfsfs)
+ goto error_0;
+
+ /* a file of servers with which we're dealing */
+ p = proc_create("servers", S_IFREG|S_IRUGO,
+ nn->proc_nfsfs, &nfs_server_list_fops);
+ if (!p)
+ goto error_1;
+
+ /* a file of volumes that we have mounted */
+ p = proc_create("volumes", S_IFREG|S_IRUGO,
+ nn->proc_nfsfs, &nfs_volume_list_fops);
+ if (!p)
+ goto error_2;
+ return 0;
+
+error_2:
+ remove_proc_entry("servers", nn->proc_nfsfs);
+error_1:
+ remove_proc_entry("fs/nfsfs", NULL);
+error_0:
+ return -ENOMEM;
+}
+
+void nfs_fs_proc_net_exit(struct net *net)
+{
+ struct nfs_net *nn = net_generic(net, nfs_net_id);
+
+ remove_proc_entry("volumes", nn->proc_nfsfs);
+ remove_proc_entry("servers", nn->proc_nfsfs);
+ remove_proc_entry("fs/nfsfs", NULL);
+}
+
/*
* initialise the /proc/fs/nfsfs/ directory
*/
@@ -1419,14 +1436,12 @@ int __init nfs_fs_proc_init(void)
goto error_0;
/* a file of servers with which we're dealing */
- p = proc_create("servers", S_IFREG|S_IRUGO,
- proc_fs_nfs, &nfs_server_list_fops);
+ p = proc_symlink("servers", proc_fs_nfs, "../../net/nfsfs/servers");
if (!p)
goto error_1;
/* a file of volumes that we have mounted */
- p = proc_create("volumes", S_IFREG|S_IRUGO,
- proc_fs_nfs, &nfs_volume_list_fops);
+ p = proc_symlink("volumes", proc_fs_nfs, "../../net/nfsfs/volumes");
if (!p)
goto error_2;
return 0;
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index abd37a380535..68921b01b792 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1840,11 +1840,12 @@ EXPORT_SYMBOL_GPL(nfs_net_id);
static int nfs_net_init(struct net *net)
{
nfs_clients_init(net);
- return 0;
+ return nfs_fs_proc_net_init(net);
}
static void nfs_net_exit(struct net *net)
{
+ nfs_fs_proc_net_exit(net);
nfs_cleanup_cb_ident_idr(net);
}
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 617f36611d4a..e2a45ae5014e 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -195,7 +195,16 @@ extern struct rpc_clnt *nfs4_find_or_create_ds_client(struct nfs_client *,
#ifdef CONFIG_PROC_FS
extern int __init nfs_fs_proc_init(void);
extern void nfs_fs_proc_exit(void);
+extern int nfs_fs_proc_net_init(struct net *net);
+extern void nfs_fs_proc_net_exit(struct net *net);
#else
+static inline int nfs_fs_proc_net_init(struct net *net)
+{
+ return 0;
+}
+static inline void nfs_fs_proc_net_exit(struct net *net)
+{
+}
static inline int nfs_fs_proc_init(void)
{
return 0;
diff --git a/fs/nfs/netns.h b/fs/nfs/netns.h
index 8ee1fab83268..ef221fb8a183 100644
--- a/fs/nfs/netns.h
+++ b/fs/nfs/netns.h
@@ -29,6 +29,9 @@ struct nfs_net {
#endif
spinlock_t nfs_client_lock;
struct timespec boot_time;
+#ifdef CONFIG_PROC_FS
+ struct proc_dir_entry *proc_nfsfs;
+#endif
};
extern int nfs_net_id;
diff --git a/fs/proc/Makefile b/fs/proc/Makefile
index 239493ec718e..7151ea428041 100644
--- a/fs/proc/Makefile
+++ b/fs/proc/Makefile
@@ -23,6 +23,7 @@ proc-y += version.o
proc-y += softirqs.o
proc-y += namespaces.o
proc-y += self.o
+proc-y += thread_self.o
proc-$(CONFIG_PROC_SYSCTL) += proc_sysctl.o
proc-$(CONFIG_NET) += proc_net.o
proc-$(CONFIG_PROC_KCORE) += kcore.o
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 043c83cb51f9..baf852b648ad 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2814,7 +2814,7 @@ retry:
return iter;
}
-#define TGID_OFFSET (FIRST_PROCESS_ENTRY + 1)
+#define TGID_OFFSET (FIRST_PROCESS_ENTRY + 2)
/* for the /proc/ directory itself, after non-process stuff has been done */
int proc_pid_readdir(struct file *file, struct dir_context *ctx)
@@ -2826,14 +2826,19 @@ int proc_pid_readdir(struct file *file, struct dir_context *ctx)
if (pos >= PID_MAX_LIMIT + TGID_OFFSET)
return 0;
- if (pos == TGID_OFFSET - 1) {
+ if (pos == TGID_OFFSET - 2) {
struct inode *inode = ns->proc_self->d_inode;
if (!dir_emit(ctx, "self", 4, inode->i_ino, DT_LNK))
return 0;
- iter.tgid = 0;
- } else {
- iter.tgid = pos - TGID_OFFSET;
+ ctx->pos = pos = pos + 1;
+ }
+ if (pos == TGID_OFFSET - 1) {
+ struct inode *inode = ns->proc_thread_self->d_inode;
+ if (!dir_emit(ctx, "thread-self", 11, inode->i_ino, DT_LNK))
+ return 0;
+ ctx->pos = pos = pos + 1;
}
+ iter.tgid = pos - TGID_OFFSET;
iter.task = NULL;
for (iter = next_tgid(ns, iter);
iter.task;
@@ -2862,6 +2867,9 @@ static const struct pid_entry tid_base_stuff[] = {
DIR("fd", S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
DIR("fdinfo", S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
DIR("ns", S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
+#ifdef CONFIG_NET
+ DIR("net", S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
+#endif
REG("environ", S_IRUSR, proc_environ_operations),
ONE("auxv", S_IRUSR, proc_pid_auxv),
ONE("status", S_IRUGO, proc_pid_status),
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 0adbc02d60e3..333080d7a671 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -442,6 +442,7 @@ struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
int proc_fill_super(struct super_block *s)
{
struct inode *root_inode;
+ int ret;
s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC;
s->s_blocksize = 1024;
@@ -463,5 +464,9 @@ int proc_fill_super(struct super_block *s)
return -ENOMEM;
}
- return proc_setup_self(s);
+ ret = proc_setup_self(s);
+ if (ret) {
+ return ret;
+ }
+ return proc_setup_thread_self(s);
}
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index a024cf7b260f..7da13e49128a 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -231,6 +231,12 @@ static inline int proc_net_init(void) { return 0; }
extern int proc_setup_self(struct super_block *);
/*
+ * proc_thread_self.c
+ */
+extern int proc_setup_thread_self(struct super_block *);
+extern void proc_thread_self_init(void);
+
+/*
* proc_sysctl.c
*/
#ifdef CONFIG_PROC_SYSCTL
diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c
index 4677bb7dc7c2..39481028ec08 100644
--- a/fs/proc/proc_net.c
+++ b/fs/proc/proc_net.c
@@ -113,9 +113,11 @@ static struct net *get_proc_task_net(struct inode *dir)
rcu_read_lock();
task = pid_task(proc_pid(dir), PIDTYPE_PID);
if (task != NULL) {
- ns = task_nsproxy(task);
+ task_lock(task);
+ ns = task->nsproxy;
if (ns != NULL)
net = get_net(ns->net_ns);
+ task_unlock(task);
}
rcu_read_unlock();
@@ -224,7 +226,7 @@ static struct pernet_operations __net_initdata proc_net_ns_ops = {
int __init proc_net_init(void)
{
- proc_symlink("net", NULL, "self/net");
+ proc_symlink("net", NULL, "thread-self/net");
return register_pernet_subsys(&proc_net_ns_ops);
}
diff --git a/fs/proc/root.c b/fs/proc/root.c
index 574bafc41f0b..6296c7626963 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -149,6 +149,8 @@ static void proc_kill_sb(struct super_block *sb)
ns = (struct pid_namespace *)sb->s_fs_info;
if (ns->proc_self)
dput(ns->proc_self);
+ if (ns->proc_thread_self)
+ dput(ns->proc_thread_self);
kill_anon_super(sb);
put_pid_ns(ns);
}
@@ -170,7 +172,8 @@ void __init proc_root_init(void)
return;
proc_self_init();
- proc_symlink("mounts", NULL, "self/mounts");
+ proc_thread_self_init();
+ proc_symlink("mounts", NULL, "thread-self/mounts");
proc_net_init();
diff --git a/fs/proc/thread_self.c b/fs/proc/thread_self.c
new file mode 100644
index 000000000000..59075b509df3
--- /dev/null
+++ b/fs/proc/thread_self.c
@@ -0,0 +1,85 @@
+#include <linux/sched.h>
+#include <linux/namei.h>
+#include <linux/slab.h>
+#include <linux/pid_namespace.h>
+#include "internal.h"
+
+/*
+ * /proc/thread_self:
+ */
+static int proc_thread_self_readlink(struct dentry *dentry, char __user *buffer,
+ int buflen)
+{
+ struct pid_namespace *ns = dentry->d_sb->s_fs_info;
+ pid_t tgid = task_tgid_nr_ns(current, ns);
+ pid_t pid = task_pid_nr_ns(current, ns);
+ char tmp[PROC_NUMBUF + 6 + PROC_NUMBUF];
+ if (!pid)
+ return -ENOENT;
+ sprintf(tmp, "%d/task/%d", tgid, pid);
+ return readlink_copy(buffer, buflen, tmp);
+}
+
+static void *proc_thread_self_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+ struct pid_namespace *ns = dentry->d_sb->s_fs_info;
+ pid_t tgid = task_tgid_nr_ns(current, ns);
+ pid_t pid = task_pid_nr_ns(current, ns);
+ char *name = ERR_PTR(-ENOENT);
+ if (pid) {
+ name = kmalloc(PROC_NUMBUF + 6 + PROC_NUMBUF, GFP_KERNEL);
+ if (!name)
+ name = ERR_PTR(-ENOMEM);
+ else
+ sprintf(name, "%d/task/%d", tgid, pid);
+ }
+ nd_set_link(nd, name);
+ return NULL;
+}
+
+static const struct inode_operations proc_thread_self_inode_operations = {
+ .readlink = proc_thread_self_readlink,
+ .follow_link = proc_thread_self_follow_link,
+ .put_link = kfree_put_link,
+};
+
+static unsigned thread_self_inum;
+
+int proc_setup_thread_self(struct super_block *s)
+{
+ struct inode *root_inode = s->s_root->d_inode;
+ struct pid_namespace *ns = s->s_fs_info;
+ struct dentry *thread_self;
+
+ mutex_lock(&root_inode->i_mutex);
+ thread_self = d_alloc_name(s->s_root, "thread-self");
+ if (thread_self) {
+ struct inode *inode = new_inode_pseudo(s);
+ if (inode) {
+ inode->i_ino = thread_self_inum;
+ inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
+ inode->i_mode = S_IFLNK | S_IRWXUGO;
+ inode->i_uid = GLOBAL_ROOT_UID;
+ inode->i_gid = GLOBAL_ROOT_GID;
+ inode->i_op = &proc_thread_self_inode_operations;
+ d_add(thread_self, inode);
+ } else {
+ dput(thread_self);
+ thread_self = ERR_PTR(-ENOMEM);
+ }
+ } else {
+ thread_self = ERR_PTR(-ENOMEM);
+ }
+ mutex_unlock(&root_inode->i_mutex);
+ if (IS_ERR(thread_self)) {
+ pr_err("proc_fill_super: can't allocate /proc/thread_self\n");
+ return PTR_ERR(thread_self);
+ }
+ ns->proc_thread_self = thread_self;
+ return 0;
+}
+
+void __init proc_thread_self_init(void)
+{
+ proc_alloc_inum(&thread_self_inum);
+}
diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c
index 1a81373947f3..73ca1740d839 100644
--- a/fs/proc_namespace.c
+++ b/fs/proc_namespace.c
@@ -232,17 +232,15 @@ static int mounts_open_common(struct inode *inode, struct file *file,
if (!task)
goto err;
- rcu_read_lock();
- nsp = task_nsproxy(task);
+ task_lock(task);
+ nsp = task->nsproxy;
if (!nsp || !nsp->mnt_ns) {
- rcu_read_unlock();
+ task_unlock(task);
put_task_struct(task);
goto err;
}
ns = nsp->mnt_ns;
get_mnt_ns(ns);
- rcu_read_unlock();
- task_lock(task);
if (!task->fs) {
task_unlock(task);
put_task_struct(task);
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;
diff --git a/ipc/namespace.c b/ipc/namespace.c
index 59451c1e214d..b54468e48e32 100644
--- a/ipc/namespace.c
+++ b/ipc/namespace.c
@@ -154,11 +154,11 @@ static void *ipcns_get(struct task_struct *task)
struct ipc_namespace *ns = NULL;
struct nsproxy *nsproxy;
- rcu_read_lock();
- nsproxy = task_nsproxy(task);
+ task_lock(task);
+ nsproxy = task->nsproxy;
if (nsproxy)
ns = get_ipc_ns(nsproxy->ipc_ns);
- rcu_read_unlock();
+ task_unlock(task);
return ns;
}
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index 8e7811086b82..ef42d0ab3115 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -204,20 +204,13 @@ void switch_task_namespaces(struct task_struct *p, struct nsproxy *new)
might_sleep();
+ task_lock(p);
ns = p->nsproxy;
+ p->nsproxy = new;
+ task_unlock(p);
- rcu_assign_pointer(p->nsproxy, new);
-
- if (ns && atomic_dec_and_test(&ns->count)) {
- /*
- * wait for others to get what they want from this nsproxy.
- *
- * cannot release this nsproxy via the call_rcu() since
- * put_mnt_ns() will want to sleep
- */
- synchronize_rcu();
+ if (ns && atomic_dec_and_test(&ns->count))
free_nsproxy(ns);
- }
}
void exit_task_namespaces(struct task_struct *p)
diff --git a/kernel/utsname.c b/kernel/utsname.c
index fd393124e507..883aaaa7de8a 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -93,13 +93,13 @@ static void *utsns_get(struct task_struct *task)
struct uts_namespace *ns = NULL;
struct nsproxy *nsproxy;
- rcu_read_lock();
- nsproxy = task_nsproxy(task);
+ task_lock(task);
+ nsproxy = task->nsproxy;
if (nsproxy) {
ns = nsproxy->uts_ns;
get_uts_ns(ns);
}
- rcu_read_unlock();
+ task_unlock(task);
return ns;
}
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 85b62691f4f2..7c6b51a58968 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -373,9 +373,11 @@ struct net *get_net_ns_by_pid(pid_t pid)
tsk = find_task_by_vpid(pid);
if (tsk) {
struct nsproxy *nsproxy;
- nsproxy = task_nsproxy(tsk);
+ task_lock(tsk);
+ nsproxy = tsk->nsproxy;
if (nsproxy)
net = get_net(nsproxy->net_ns);
+ task_unlock(tsk);
}
rcu_read_unlock();
return net;
@@ -632,11 +634,11 @@ static void *netns_get(struct task_struct *task)
struct net *net = NULL;
struct nsproxy *nsproxy;
- rcu_read_lock();
- nsproxy = task_nsproxy(task);
+ task_lock(task);
+ nsproxy = task->nsproxy;
if (nsproxy)
net = get_net(nsproxy->net_ns);
- rcu_read_unlock();
+ task_unlock(task);
return net;
}
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 6fd2a4402069..36ff2e4c7b6f 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -5,6 +5,7 @@ TARGETS += kcmp
TARGETS += memfd
TARGETS += memory-hotplug
TARGETS += mqueue
+TARGETS += mount
TARGETS += net
TARGETS += ptrace
TARGETS += timers
diff --git a/tools/testing/selftests/mount/Makefile b/tools/testing/selftests/mount/Makefile
new file mode 100644
index 000000000000..337d853c2b72
--- /dev/null
+++ b/tools/testing/selftests/mount/Makefile
@@ -0,0 +1,17 @@
+# Makefile for mount selftests.
+
+all: unprivileged-remount-test
+
+unprivileged-remount-test: unprivileged-remount-test.c
+ gcc -Wall -O2 unprivileged-remount-test.c -o unprivileged-remount-test
+
+# Allow specific tests to be selected.
+test_unprivileged_remount: unprivileged-remount-test
+ @if [ -f /proc/self/uid_map ] ; then ./unprivileged-remount-test ; fi
+
+run_tests: all test_unprivileged_remount
+
+clean:
+ rm -f unprivileged-remount-test
+
+.PHONY: all test_unprivileged_remount
diff --git a/tools/testing/selftests/mount/unprivileged-remount-test.c b/tools/testing/selftests/mount/unprivileged-remount-test.c
new file mode 100644
index 000000000000..1b3ff2fda4d0
--- /dev/null
+++ b/tools/testing/selftests/mount/unprivileged-remount-test.c
@@ -0,0 +1,242 @@
+#define _GNU_SOURCE
+#include <sched.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/mount.h>
+#include <sys/wait.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <grp.h>
+#include <stdbool.h>
+#include <stdarg.h>
+
+#ifndef CLONE_NEWNS
+# define CLONE_NEWNS 0x00020000
+#endif
+#ifndef CLONE_NEWUTS
+# define CLONE_NEWUTS 0x04000000
+#endif
+#ifndef CLONE_NEWIPC
+# define CLONE_NEWIPC 0x08000000
+#endif
+#ifndef CLONE_NEWNET
+# define CLONE_NEWNET 0x40000000
+#endif
+#ifndef CLONE_NEWUSER
+# define CLONE_NEWUSER 0x10000000
+#endif
+#ifndef CLONE_NEWPID
+# define CLONE_NEWPID 0x20000000
+#endif
+
+#ifndef MS_RELATIME
+#define MS_RELATIME (1 << 21)
+#endif
+#ifndef MS_STRICTATIME
+#define MS_STRICTATIME (1 << 24)
+#endif
+
+static void die(char *fmt, ...)
+{
+ va_list ap;
+ va_start(ap, fmt);
+ vfprintf(stderr, fmt, ap);
+ va_end(ap);
+ exit(EXIT_FAILURE);
+}
+
+static void write_file(char *filename, char *fmt, ...)
+{
+ char buf[4096];
+ int fd;
+ ssize_t written;
+ int buf_len;
+ va_list ap;
+
+ va_start(ap, fmt);
+ buf_len = vsnprintf(buf, sizeof(buf), fmt, ap);
+ va_end(ap);
+ if (buf_len < 0) {
+ die("vsnprintf failed: %s\n",
+ strerror(errno));
+ }
+ if (buf_len >= sizeof(buf)) {
+ die("vsnprintf output truncated\n");
+ }
+
+ fd = open(filename, O_WRONLY);
+ if (fd < 0) {
+ die("open of %s failed: %s\n",
+ filename, strerror(errno));
+ }
+ written = write(fd, buf, buf_len);
+ if (written != buf_len) {
+ if (written >= 0) {
+ die("short write to %s\n", filename);
+ } else {
+ die("write to %s failed: %s\n",
+ filename, strerror(errno));
+ }
+ }
+ if (close(fd) != 0) {
+ die("close of %s failed: %s\n",
+ filename, strerror(errno));
+ }
+}
+
+static void create_and_enter_userns(void)
+{
+ uid_t uid;
+ gid_t gid;
+
+ uid = getuid();
+ gid = getgid();
+
+ if (unshare(CLONE_NEWUSER) !=0) {
+ die("unshare(CLONE_NEWUSER) failed: %s\n",
+ strerror(errno));
+ }
+
+ write_file("/proc/self/uid_map", "0 %d 1", uid);
+ write_file("/proc/self/gid_map", "0 %d 1", gid);
+
+ if (setgroups(0, NULL) != 0) {
+ die("setgroups failed: %s\n",
+ strerror(errno));
+ }
+ if (setgid(0) != 0) {
+ die ("setgid(0) failed %s\n",
+ strerror(errno));
+ }
+ if (setuid(0) != 0) {
+ die("setuid(0) failed %s\n",
+ strerror(errno));
+ }
+}
+
+static
+bool test_unpriv_remount(int mount_flags, int remount_flags, int invalid_flags)
+{
+ pid_t child;
+
+ child = fork();
+ if (child == -1) {
+ die("fork failed: %s\n",
+ strerror(errno));
+ }
+ if (child != 0) { /* parent */
+ pid_t pid;
+ int status;
+ pid = waitpid(child, &status, 0);
+ if (pid == -1) {
+ die("waitpid failed: %s\n",
+ strerror(errno));
+ }
+ if (pid != child) {
+ die("waited for %d got %d\n",
+ child, pid);
+ }
+ if (!WIFEXITED(status)) {
+ die("child did not terminate cleanly\n");
+ }
+ return WEXITSTATUS(status) == EXIT_SUCCESS ? true : false;
+ }
+
+ create_and_enter_userns();
+ if (unshare(CLONE_NEWNS) != 0) {
+ die("unshare(CLONE_NEWNS) failed: %s\n",
+ strerror(errno));
+ }
+
+ if (mount("testing", "/tmp", "ramfs", mount_flags, NULL) != 0) {
+ die("mount of /tmp failed: %s\n",
+ strerror(errno));
+ }
+
+ create_and_enter_userns();
+
+ if (unshare(CLONE_NEWNS) != 0) {
+ die("unshare(CLONE_NEWNS) failed: %s\n",
+ strerror(errno));
+ }
+
+ if (mount("/tmp", "/tmp", "none",
+ MS_REMOUNT | MS_BIND | remount_flags, NULL) != 0) {
+ /* system("cat /proc/self/mounts"); */
+ die("remount of /tmp failed: %s\n",
+ strerror(errno));
+ }
+
+ if (mount("/tmp", "/tmp", "none",
+ MS_REMOUNT | MS_BIND | invalid_flags, NULL) == 0) {
+ /* system("cat /proc/self/mounts"); */
+ die("remount of /tmp with invalid flags "
+ "succeeded unexpectedly\n");
+ }
+ exit(EXIT_SUCCESS);
+}
+
+static bool test_unpriv_remount_simple(int mount_flags)
+{
+ return test_unpriv_remount(mount_flags, mount_flags, 0);
+}
+
+static bool test_unpriv_remount_atime(int mount_flags, int invalid_flags)
+{
+ return test_unpriv_remount(mount_flags, mount_flags, invalid_flags);
+}
+
+int main(int argc, char **argv)
+{
+ if (!test_unpriv_remount_simple(MS_RDONLY|MS_NODEV)) {
+ die("MS_RDONLY malfunctions\n");
+ }
+ if (!test_unpriv_remount_simple(MS_NODEV)) {
+ die("MS_NODEV malfunctions\n");
+ }
+ if (!test_unpriv_remount_simple(MS_NOSUID|MS_NODEV)) {
+ die("MS_NOSUID malfunctions\n");
+ }
+ if (!test_unpriv_remount_simple(MS_NOEXEC|MS_NODEV)) {
+ die("MS_NOEXEC malfunctions\n");
+ }
+ if (!test_unpriv_remount_atime(MS_RELATIME|MS_NODEV,
+ MS_NOATIME|MS_NODEV))
+ {
+ die("MS_RELATIME malfunctions\n");
+ }
+ if (!test_unpriv_remount_atime(MS_STRICTATIME|MS_NODEV,
+ MS_NOATIME|MS_NODEV))
+ {
+ die("MS_STRICTATIME malfunctions\n");
+ }
+ if (!test_unpriv_remount_atime(MS_NOATIME|MS_NODEV,
+ MS_STRICTATIME|MS_NODEV))
+ {
+ die("MS_RELATIME malfunctions\n");
+ }
+ if (!test_unpriv_remount_atime(MS_RELATIME|MS_NODIRATIME|MS_NODEV,
+ MS_NOATIME|MS_NODEV))
+ {
+ die("MS_RELATIME malfunctions\n");
+ }
+ if (!test_unpriv_remount_atime(MS_STRICTATIME|MS_NODIRATIME|MS_NODEV,
+ MS_NOATIME|MS_NODEV))
+ {
+ die("MS_RELATIME malfunctions\n");
+ }
+ if (!test_unpriv_remount_atime(MS_NOATIME|MS_NODIRATIME|MS_NODEV,
+ MS_STRICTATIME|MS_NODEV))
+ {
+ die("MS_RELATIME malfunctions\n");
+ }
+ if (!test_unpriv_remount(MS_STRICTATIME|MS_NODEV, MS_NODEV,
+ MS_NOATIME|MS_NODEV))
+ {
+ die("Default atime malfunctions\n");
+ }
+ return EXIT_SUCCESS;
+}