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- // SPDX-License-Identifier: GPL-2.0
- #include <linux/sched/signal.h>
- #include <linux/errno.h>
- #include <linux/dcache.h>
- #include <linux/path.h>
- #include <linux/fdtable.h>
- #include <linux/namei.h>
- #include <linux/pid.h>
- #include <linux/ptrace.h>
- #include <linux/security.h>
- #include <linux/file.h>
- #include <linux/seq_file.h>
- #include <linux/fs.h>
- #include <linux/proc_fs.h>
- #ifdef CONFIG_KSU_SUSFS_SUS_MOUNT
- #include <linux/susfs_def.h>
- #endif
- #include "../mount.h"
- #include "internal.h"
- #include "fd.h"
- static int seq_show(struct seq_file *m, void *v)
- {
- struct files_struct *files = NULL;
- int f_flags = 0, ret = -ENOENT;
- struct file *file = NULL;
- struct task_struct *task;
- #ifdef CONFIG_KSU_SUSFS_SUS_MOUNT
- struct mount *mnt = NULL;
- #endif
- task = get_proc_task(m->private);
- if (!task)
- return -ENOENT;
- task_lock(task);
- files = task->files;
- if (files) {
- unsigned int fd = proc_fd(m->private);
- spin_lock(&files->file_lock);
- file = files_lookup_fd_locked(files, fd);
- if (file) {
- struct fdtable *fdt = files_fdtable(files);
- f_flags = file->f_flags;
- if (close_on_exec(fd, fdt))
- f_flags |= O_CLOEXEC;
- get_file(file);
- ret = 0;
- }
- spin_unlock(&files->file_lock);
- }
- task_unlock(task);
- put_task_struct(task);
- if (ret)
- return ret;
- #ifdef CONFIG_KSU_SUSFS_SUS_MOUNT
- mnt = real_mount(file->f_path.mnt);
- if (likely(current->susfs_task_state & TASK_STRUCT_NON_ROOT_USER_APP_PROC) &&
- mnt->mnt_id >= DEFAULT_SUS_MNT_ID) {
- struct path path;
- char *pathname = kmalloc(PAGE_SIZE, GFP_KERNEL);
- char *dpath;
- for (; mnt->mnt_id >= DEFAULT_SUS_MNT_ID; mnt = mnt->mnt_parent) { }
- if (!pathname) {
- goto out_seq_printf;
- }
- dpath = d_path(&file->f_path, pathname, PAGE_SIZE);
- if (!dpath) {
- goto out_free_pathname;
- }
- if (kern_path(dpath, 0, &path)) {
- goto out_free_pathname;
- }
- seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\nino:\t%lu\n",
- (long long)file->f_pos, f_flags,
- mnt->mnt_id,
- path.dentry->d_inode->i_ino);
- path_put(&path);
- kfree(pathname);
- goto bypass_orig_flow;
- out_free_pathname:
- kfree(pathname);
- }
- out_seq_printf:
- seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\nino:\t%lu\n",
- (long long)file->f_pos, f_flags,
- mnt->mnt_id,
- file_inode(file)->i_ino);
- bypass_orig_flow:
- #else
- seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\nino:\t%lu\n",
- (long long)file->f_pos, f_flags,
- real_mount(file->f_path.mnt)->mnt_id,
- file_inode(file)->i_ino);
- #endif
- /* show_fd_locks() never deferences files so a stale value is safe */
- show_fd_locks(m, file, files);
- if (seq_has_overflowed(m))
- goto out;
- if (file->f_op->show_fdinfo)
- file->f_op->show_fdinfo(m, file);
- out:
- fput(file);
- return 0;
- }
- static int proc_fdinfo_access_allowed(struct inode *inode)
- {
- bool allowed = false;
- struct task_struct *task = get_proc_task(inode);
- if (!task)
- return -ESRCH;
- allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
- put_task_struct(task);
- if (!allowed)
- return -EACCES;
- return 0;
- }
- static int seq_fdinfo_open(struct inode *inode, struct file *file)
- {
- int ret = proc_fdinfo_access_allowed(inode);
- if (ret)
- return ret;
- return single_open(file, seq_show, inode);
- }
- static const struct file_operations proc_fdinfo_file_operations = {
- .open = seq_fdinfo_open,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = single_release,
- };
- static bool tid_fd_mode(struct task_struct *task, unsigned fd, fmode_t *mode)
- {
- struct file *file;
- rcu_read_lock();
- file = task_lookup_fd_rcu(task, fd);
- if (file)
- *mode = file->f_mode;
- rcu_read_unlock();
- return !!file;
- }
- static void tid_fd_update_inode(struct task_struct *task, struct inode *inode,
- fmode_t f_mode)
- {
- task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
- if (S_ISLNK(inode->i_mode)) {
- unsigned i_mode = S_IFLNK;
- if (f_mode & FMODE_READ)
- i_mode |= S_IRUSR | S_IXUSR;
- if (f_mode & FMODE_WRITE)
- i_mode |= S_IWUSR | S_IXUSR;
- inode->i_mode = i_mode;
- }
- security_task_to_inode(task, inode);
- }
- static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
- {
- struct task_struct *task;
- struct inode *inode;
- unsigned int fd;
- if (flags & LOOKUP_RCU)
- return -ECHILD;
- inode = d_inode(dentry);
- task = get_proc_task(inode);
- fd = proc_fd(inode);
- if (task) {
- fmode_t f_mode;
- if (tid_fd_mode(task, fd, &f_mode)) {
- tid_fd_update_inode(task, inode, f_mode);
- put_task_struct(task);
- return 1;
- }
- put_task_struct(task);
- }
- return 0;
- }
- static const struct dentry_operations tid_fd_dentry_operations = {
- .d_revalidate = tid_fd_revalidate,
- .d_delete = pid_delete_dentry,
- };
- static int proc_fd_link(struct dentry *dentry, struct path *path)
- {
- struct task_struct *task;
- int ret = -ENOENT;
- task = get_proc_task(d_inode(dentry));
- if (task) {
- unsigned int fd = proc_fd(d_inode(dentry));
- struct file *fd_file;
- fd_file = fget_task(task, fd);
- if (fd_file) {
- *path = fd_file->f_path;
- path_get(&fd_file->f_path);
- ret = 0;
- fput(fd_file);
- }
- put_task_struct(task);
- }
- return ret;
- }
- struct fd_data {
- fmode_t mode;
- unsigned fd;
- };
- static struct dentry *proc_fd_instantiate(struct dentry *dentry,
- struct task_struct *task, const void *ptr)
- {
- const struct fd_data *data = ptr;
- struct proc_inode *ei;
- struct inode *inode;
- inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK);
- if (!inode)
- return ERR_PTR(-ENOENT);
- ei = PROC_I(inode);
- ei->fd = data->fd;
- inode->i_op = &proc_pid_link_inode_operations;
- inode->i_size = 64;
- ei->op.proc_get_link = proc_fd_link;
- tid_fd_update_inode(task, inode, data->mode);
- d_set_d_op(dentry, &tid_fd_dentry_operations);
- return d_splice_alias(inode, dentry);
- }
- static struct dentry *proc_lookupfd_common(struct inode *dir,
- struct dentry *dentry,
- instantiate_t instantiate)
- {
- struct task_struct *task = get_proc_task(dir);
- struct fd_data data = {.fd = name_to_int(&dentry->d_name)};
- struct dentry *result = ERR_PTR(-ENOENT);
- if (!task)
- goto out_no_task;
- if (data.fd == ~0U)
- goto out;
- if (!tid_fd_mode(task, data.fd, &data.mode))
- goto out;
- result = instantiate(dentry, task, &data);
- out:
- put_task_struct(task);
- out_no_task:
- return result;
- }
- static int proc_readfd_common(struct file *file, struct dir_context *ctx,
- instantiate_t instantiate)
- {
- struct task_struct *p = get_proc_task(file_inode(file));
- unsigned int fd;
- if (!p)
- return -ENOENT;
- if (!dir_emit_dots(file, ctx))
- goto out;
- rcu_read_lock();
- for (fd = ctx->pos - 2;; fd++) {
- struct file *f;
- struct fd_data data;
- char name[10 + 1];
- unsigned int len;
- f = task_lookup_next_fd_rcu(p, &fd);
- ctx->pos = fd + 2LL;
- if (!f)
- break;
- data.mode = f->f_mode;
- rcu_read_unlock();
- data.fd = fd;
- len = snprintf(name, sizeof(name), "%u", fd);
- if (!proc_fill_cache(file, ctx,
- name, len, instantiate, p,
- &data))
- goto out;
- cond_resched();
- rcu_read_lock();
- }
- rcu_read_unlock();
- out:
- put_task_struct(p);
- return 0;
- }
- static int proc_readfd(struct file *file, struct dir_context *ctx)
- {
- return proc_readfd_common(file, ctx, proc_fd_instantiate);
- }
- const struct file_operations proc_fd_operations = {
- .read = generic_read_dir,
- .iterate_shared = proc_readfd,
- .llseek = generic_file_llseek,
- };
- static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
- unsigned int flags)
- {
- return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
- }
- /*
- * /proc/pid/fd needs a special permission handler so that a process can still
- * access /proc/self/fd after it has executed a setuid().
- */
- int proc_fd_permission(struct user_namespace *mnt_userns,
- struct inode *inode, int mask)
- {
- struct task_struct *p;
- int rv;
- rv = generic_permission(&init_user_ns, inode, mask);
- if (rv == 0)
- return rv;
- rcu_read_lock();
- p = pid_task(proc_pid(inode), PIDTYPE_PID);
- if (p && same_thread_group(p, current))
- rv = 0;
- rcu_read_unlock();
- return rv;
- }
- const struct inode_operations proc_fd_inode_operations = {
- .lookup = proc_lookupfd,
- .permission = proc_fd_permission,
- .setattr = proc_setattr,
- };
- static struct dentry *proc_fdinfo_instantiate(struct dentry *dentry,
- struct task_struct *task, const void *ptr)
- {
- const struct fd_data *data = ptr;
- struct proc_inode *ei;
- struct inode *inode;
- inode = proc_pid_make_inode(dentry->d_sb, task, S_IFREG | S_IRUGO);
- if (!inode)
- return ERR_PTR(-ENOENT);
- ei = PROC_I(inode);
- ei->fd = data->fd;
- inode->i_fop = &proc_fdinfo_file_operations;
- tid_fd_update_inode(task, inode, 0);
- d_set_d_op(dentry, &tid_fd_dentry_operations);
- return d_splice_alias(inode, dentry);
- }
- static struct dentry *
- proc_lookupfdinfo(struct inode *dir, struct dentry *dentry, unsigned int flags)
- {
- return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
- }
- static int proc_readfdinfo(struct file *file, struct dir_context *ctx)
- {
- return proc_readfd_common(file, ctx,
- proc_fdinfo_instantiate);
- }
- static int proc_open_fdinfo(struct inode *inode, struct file *file)
- {
- int ret = proc_fdinfo_access_allowed(inode);
- if (ret)
- return ret;
- return 0;
- }
- const struct inode_operations proc_fdinfo_inode_operations = {
- .lookup = proc_lookupfdinfo,
- .setattr = proc_setattr,
- };
- const struct file_operations proc_fdinfo_operations = {
- .open = proc_open_fdinfo,
- .read = generic_read_dir,
- .iterate_shared = proc_readfdinfo,
- .llseek = generic_file_llseek,
- };
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