diff options
Diffstat (limited to 'fs/proc/namespaces.c')
| -rw-r--r-- | fs/proc/namespaces.c | 185 |
1 files changed, 164 insertions, 21 deletions
diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c index b178ed733c3..b7a47196c8c 100644 --- a/fs/proc/namespaces.c +++ b/fs/proc/namespaces.c @@ -11,6 +11,7 @@ #include <net/net_namespace.h> #include <linux/ipc_namespace.h> #include <linux/pid_namespace.h> +#include <linux/user_namespace.h> #include "internal.h" @@ -24,12 +25,168 @@ static const struct proc_ns_operations *ns_entries[] = { #ifdef CONFIG_IPC_NS &ipcns_operations, #endif +#ifdef CONFIG_PID_NS + &pidns_operations, +#endif +#ifdef CONFIG_USER_NS + &userns_operations, +#endif + &mntns_operations, }; static const struct file_operations ns_file_operations = { .llseek = no_llseek, }; +static const struct inode_operations ns_inode_operations = { + .setattr = proc_setattr, +}; + +static int ns_delete_dentry(const struct dentry *dentry) +{ + /* Don't cache namespace inodes when not in use */ + return 1; +} + +static char *ns_dname(struct dentry *dentry, char *buffer, int buflen) +{ + struct inode *inode = dentry->d_inode; + const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops; + + return dynamic_dname(dentry, buffer, buflen, "%s:[%lu]", + ns_ops->name, inode->i_ino); +} + +const struct dentry_operations ns_dentry_operations = +{ + .d_delete = ns_delete_dentry, + .d_dname = ns_dname, +}; + +static struct dentry *proc_ns_get_dentry(struct super_block *sb, + struct task_struct *task, const struct proc_ns_operations *ns_ops) +{ + struct dentry *dentry, *result; + struct inode *inode; + struct proc_inode *ei; + struct qstr qname = { .name = "", }; + void *ns; + + ns = ns_ops->get(task); + if (!ns) + return ERR_PTR(-ENOENT); + + dentry = d_alloc_pseudo(sb, &qname); + if (!dentry) { + ns_ops->put(ns); + return ERR_PTR(-ENOMEM); + } + + inode = iget_locked(sb, ns_ops->inum(ns)); + if (!inode) { + dput(dentry); + ns_ops->put(ns); + return ERR_PTR(-ENOMEM); + } + + ei = PROC_I(inode); + if (inode->i_state & I_NEW) { + inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; + inode->i_op = &ns_inode_operations; + inode->i_mode = S_IFREG | S_IRUGO; + inode->i_fop = &ns_file_operations; + ei->ns_ops = ns_ops; + ei->ns = ns; + unlock_new_inode(inode); + } else { + ns_ops->put(ns); + } + + d_set_d_op(dentry, &ns_dentry_operations); + result = d_instantiate_unique(dentry, inode); + if (result) { + dput(dentry); + dentry = result; + } + + return dentry; +} + +static void *proc_ns_follow_link(struct dentry *dentry, struct nameidata *nd) +{ + struct inode *inode = dentry->d_inode; + struct super_block *sb = inode->i_sb; + struct proc_inode *ei = PROC_I(inode); + struct task_struct *task; + struct dentry *ns_dentry; + void *error = ERR_PTR(-EACCES); + + task = get_proc_task(inode); + if (!task) + goto out; + + if (!ptrace_may_access(task, PTRACE_MODE_READ)) + goto out_put_task; + + ns_dentry = proc_ns_get_dentry(sb, task, ei->ns_ops); + if (IS_ERR(ns_dentry)) { + error = ERR_CAST(ns_dentry); + goto out_put_task; + } + + dput(nd->path.dentry); + nd->path.dentry = ns_dentry; + error = NULL; + +out_put_task: + put_task_struct(task); +out: + return error; +} + +static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflen) +{ + struct inode *inode = dentry->d_inode; + struct proc_inode *ei = PROC_I(inode); + const struct proc_ns_operations *ns_ops = ei->ns_ops; + struct task_struct *task; + void *ns; + char name[50]; + int len = -EACCES; + + task = get_proc_task(inode); + if (!task) + goto out; + + if (!ptrace_may_access(task, PTRACE_MODE_READ)) + goto out_put_task; + + len = -ENOENT; + ns = ns_ops->get(task); + if (!ns) + goto out_put_task; + + snprintf(name, sizeof(name), "%s:[%u]", ns_ops->name, ns_ops->inum(ns)); + len = strlen(name); + + if (len > buflen) + len = buflen; + if (copy_to_user(buffer, name, len)) + len = -EFAULT; + + ns_ops->put(ns); +out_put_task: + put_task_struct(task); +out: + return len; +} + +static const struct inode_operations proc_ns_link_inode_operations = { + .readlink = proc_ns_readlink, + .follow_link = proc_ns_follow_link, + .setattr = proc_setattr, +}; + static struct dentry *proc_ns_instantiate(struct inode *dir, struct dentry *dentry, struct task_struct *task, const void *ptr) { @@ -37,21 +194,15 @@ static struct dentry *proc_ns_instantiate(struct inode *dir, struct inode *inode; struct proc_inode *ei; struct dentry *error = ERR_PTR(-ENOENT); - void *ns; inode = proc_pid_make_inode(dir->i_sb, task); if (!inode) goto out; - ns = ns_ops->get(task); - if (!ns) - goto out_iput; - ei = PROC_I(inode); - inode->i_mode = S_IFREG|S_IRUSR; - inode->i_fop = &ns_file_operations; - ei->ns_ops = ns_ops; - ei->ns = ns; + inode->i_mode = S_IFLNK|S_IRWXUGO; + inode->i_op = &proc_ns_link_inode_operations; + ei->ns_ops = ns_ops; d_set_d_op(dentry, &pid_dentry_operations); d_add(dentry, inode); @@ -60,9 +211,6 @@ static struct dentry *proc_ns_instantiate(struct inode *dir, error = NULL; out: return error; -out_iput: - iput(inode); - goto out; } static int proc_ns_fill_cache(struct file *filp, void *dirent, @@ -89,10 +237,6 @@ static int proc_ns_dir_readdir(struct file *filp, void *dirent, if (!task) goto out_no_task; - ret = -EPERM; - if (!ptrace_may_access(task, PTRACE_MODE_READ)) - goto out; - ret = 0; i = filp->f_pos; switch (i) { @@ -152,10 +296,6 @@ static struct dentry *proc_ns_dir_lookup(struct inode *dir, if (!task) goto out_no_task; - error = ERR_PTR(-EPERM); - if (!ptrace_may_access(task, PTRACE_MODE_READ)) - goto out; - last = &ns_entries[ARRAY_SIZE(ns_entries)]; for (entry = ns_entries; entry < last; entry++) { if (strlen((*entry)->name) != len) @@ -163,7 +303,6 @@ static struct dentry *proc_ns_dir_lookup(struct inode *dir, if (!memcmp(dentry->d_name.name, (*entry)->name, len)) break; } - error = ERR_PTR(-ENOENT); if (entry == last) goto out; @@ -198,3 +337,7 @@ out_invalid: return ERR_PTR(-EINVAL); } +bool proc_ns_inode(struct inode *inode) +{ + return inode->i_fop == &ns_file_operations; +} |