Revert "proc: fix races against execve() of /proc/PID/fd**"
This reverts commit aa6afca5bc.
It escalates of some of the google-chrome SELinux problems with ptrace
("Check failed: pid_ > 0. Did not find zygote process"), and Andrew
says that it is also causing mystery lockdep reports.
Reported-by: Alex Villacís Lasso <a_villacis@palosanto.com>
Requested-by: James Morris <jmorris@namei.org>
Requested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds
parent
19e0bafc36
commit
5e442a493f
1 changed files with 41 additions and 101 deletions
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@ -1652,46 +1652,12 @@ out:
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return error;
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}
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static int proc_pid_fd_link_getattr(struct vfsmount *mnt, struct dentry *dentry,
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struct kstat *stat)
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{
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struct inode *inode = dentry->d_inode;
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struct task_struct *task = get_proc_task(inode);
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int rc;
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if (task == NULL)
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return -ESRCH;
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rc = -EACCES;
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if (lock_trace(task))
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goto out_task;
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generic_fillattr(inode, stat);
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unlock_trace(task);
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rc = 0;
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out_task:
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put_task_struct(task);
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return rc;
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}
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static const struct inode_operations proc_pid_link_inode_operations = {
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.readlink = proc_pid_readlink,
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.follow_link = proc_pid_follow_link,
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.setattr = proc_setattr,
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};
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static const struct inode_operations proc_fdinfo_link_inode_operations = {
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.setattr = proc_setattr,
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.getattr = proc_pid_fd_link_getattr,
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};
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static const struct inode_operations proc_fd_link_inode_operations = {
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.readlink = proc_pid_readlink,
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.follow_link = proc_pid_follow_link,
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.setattr = proc_setattr,
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.getattr = proc_pid_fd_link_getattr,
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};
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/* building an inode */
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@ -1923,25 +1889,16 @@ out:
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static int proc_fd_info(struct inode *inode, struct path *path, char *info)
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{
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struct task_struct *task;
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struct files_struct *files;
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struct task_struct *task = get_proc_task(inode);
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struct files_struct *files = NULL;
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struct file *file;
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int fd = proc_fd(inode);
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int rc;
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task = get_proc_task(inode);
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if (!task)
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return -ENOENT;
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rc = -EACCES;
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if (lock_trace(task))
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goto out_task;
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rc = -ENOENT;
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if (task) {
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files = get_files_struct(task);
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if (files == NULL)
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goto out_unlock;
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put_task_struct(task);
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}
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if (files) {
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/*
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* We are not taking a ref to the file structure, so we must
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* hold ->file_lock.
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@ -1967,17 +1924,14 @@ static int proc_fd_info(struct inode *inode, struct path *path, char *info)
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"flags:\t0%o\n",
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(long long) file->f_pos,
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f_flags);
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rc = 0;
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} else
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rc = -ENOENT;
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spin_unlock(&files->file_lock);
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put_files_struct(files);
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out_unlock:
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unlock_trace(task);
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out_task:
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put_task_struct(task);
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return rc;
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return 0;
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}
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spin_unlock(&files->file_lock);
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put_files_struct(files);
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}
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return -ENOENT;
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}
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static int proc_fd_link(struct inode *inode, struct path *path)
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@ -2072,7 +2026,7 @@ static struct dentry *proc_fd_instantiate(struct inode *dir,
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spin_unlock(&files->file_lock);
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put_files_struct(files);
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inode->i_op = &proc_fd_link_inode_operations;
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inode->i_op = &proc_pid_link_inode_operations;
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inode->i_size = 64;
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ei->op.proc_get_link = proc_fd_link;
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d_set_d_op(dentry, &tid_fd_dentry_operations);
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@ -2104,12 +2058,7 @@ static struct dentry *proc_lookupfd_common(struct inode *dir,
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if (fd == ~0U)
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goto out;
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result = ERR_PTR(-EACCES);
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if (lock_trace(task))
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goto out;
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result = instantiate(dir, dentry, task, &fd);
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unlock_trace(task);
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out:
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put_task_struct(task);
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out_no_task:
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@ -2129,28 +2078,23 @@ static int proc_readfd_common(struct file * filp, void * dirent,
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retval = -ENOENT;
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if (!p)
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goto out_no_task;
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retval = -EACCES;
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if (lock_trace(p))
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goto out;
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retval = 0;
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fd = filp->f_pos;
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switch (fd) {
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case 0:
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if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
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goto out_unlock;
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goto out;
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filp->f_pos++;
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case 1:
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ino = parent_ino(dentry);
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if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
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goto out_unlock;
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goto out;
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filp->f_pos++;
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default:
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files = get_files_struct(p);
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if (!files)
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goto out_unlock;
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goto out;
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rcu_read_lock();
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for (fd = filp->f_pos-2;
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fd < files_fdtable(files)->max_fds;
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@ -2174,9 +2118,6 @@ static int proc_readfd_common(struct file * filp, void * dirent,
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rcu_read_unlock();
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put_files_struct(files);
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}
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out_unlock:
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unlock_trace(p);
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out:
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put_task_struct(p);
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out_no_task:
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@ -2254,7 +2195,6 @@ static struct dentry *proc_fdinfo_instantiate(struct inode *dir,
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ei->fd = fd;
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inode->i_mode = S_IFREG | S_IRUSR;
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inode->i_fop = &proc_fdinfo_file_operations;
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inode->i_op = &proc_fdinfo_link_inode_operations;
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d_set_d_op(dentry, &tid_fd_dentry_operations);
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d_add(dentry, inode);
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/* Close the race of the process dying before we return the dentry */
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