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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 /fs/proc
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 'fs/proc')
-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
7 files changed, 119 insertions, 9 deletions
diff --git a/fs/proc/Makefile b/fs/proc/Makefile
index 239493ec718..7151ea42804 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 043c83cb51f..baf852b648a 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 0adbc02d60e..333080d7a67 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 a024cf7b260..7da13e49128 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 4677bb7dc7c..39481028ec0 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 574bafc41f0..6296c762696 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 00000000000..59075b509df
--- /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);
+}