diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-09 17:10:41 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-09 17:10:41 -0700 |
commit | 77e40aae766ccbbbb0324cb92ab22e6e998375d7 (patch) | |
tree | fb4e8e840aaeeaac62249d7585249c4634886baa /fs/proc | |
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 'fs/proc')
-rw-r--r-- | fs/proc/Makefile | 1 | ||||
-rw-r--r-- | fs/proc/base.c | 18 | ||||
-rw-r--r-- | fs/proc/inode.c | 7 | ||||
-rw-r--r-- | fs/proc/internal.h | 6 | ||||
-rw-r--r-- | fs/proc/proc_net.c | 6 | ||||
-rw-r--r-- | fs/proc/root.c | 5 | ||||
-rw-r--r-- | fs/proc/thread_self.c | 85 |
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); +} |