Revert "proc: fix races against execve() of /proc/PID/fd**"
This reverts commit aa6afca5bcaba8101f3ea09d5c3e4100b2b9f0e5.
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>
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 2db1bd3..851ba3d 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1652,46 +1652,12 @@
return error;
}
-static int proc_pid_fd_link_getattr(struct vfsmount *mnt, struct dentry *dentry,
- struct kstat *stat)
-{
- struct inode *inode = dentry->d_inode;
- struct task_struct *task = get_proc_task(inode);
- int rc;
-
- if (task == NULL)
- return -ESRCH;
-
- rc = -EACCES;
- if (lock_trace(task))
- goto out_task;
-
- generic_fillattr(inode, stat);
- unlock_trace(task);
- rc = 0;
-out_task:
- put_task_struct(task);
- return rc;
-}
-
static const struct inode_operations proc_pid_link_inode_operations = {
.readlink = proc_pid_readlink,
.follow_link = proc_pid_follow_link,
.setattr = proc_setattr,
};
-static const struct inode_operations proc_fdinfo_link_inode_operations = {
- .setattr = proc_setattr,
- .getattr = proc_pid_fd_link_getattr,
-};
-
-static const struct inode_operations proc_fd_link_inode_operations = {
- .readlink = proc_pid_readlink,
- .follow_link = proc_pid_follow_link,
- .setattr = proc_setattr,
- .getattr = proc_pid_fd_link_getattr,
-};
-
/* building an inode */
@@ -1923,61 +1889,49 @@
static int proc_fd_info(struct inode *inode, struct path *path, char *info)
{
- struct task_struct *task;
- struct files_struct *files;
+ struct task_struct *task = get_proc_task(inode);
+ struct files_struct *files = NULL;
struct file *file;
int fd = proc_fd(inode);
- int rc;
- task = get_proc_task(inode);
- if (!task)
- return -ENOENT;
+ if (task) {
+ files = get_files_struct(task);
+ put_task_struct(task);
+ }
+ if (files) {
+ /*
+ * We are not taking a ref to the file structure, so we must
+ * hold ->file_lock.
+ */
+ spin_lock(&files->file_lock);
+ file = fcheck_files(files, fd);
+ if (file) {
+ unsigned int f_flags;
+ struct fdtable *fdt;
- rc = -EACCES;
- if (lock_trace(task))
- goto out_task;
+ fdt = files_fdtable(files);
+ f_flags = file->f_flags & ~O_CLOEXEC;
+ if (FD_ISSET(fd, fdt->close_on_exec))
+ f_flags |= O_CLOEXEC;
- rc = -ENOENT;
- files = get_files_struct(task);
- if (files == NULL)
- goto out_unlock;
-
- /*
- * We are not taking a ref to the file structure, so we must
- * hold ->file_lock.
- */
- spin_lock(&files->file_lock);
- file = fcheck_files(files, fd);
- if (file) {
- unsigned int f_flags;
- struct fdtable *fdt;
-
- fdt = files_fdtable(files);
- f_flags = file->f_flags & ~O_CLOEXEC;
- if (FD_ISSET(fd, fdt->close_on_exec))
- f_flags |= O_CLOEXEC;
-
- if (path) {
- *path = file->f_path;
- path_get(&file->f_path);
+ if (path) {
+ *path = file->f_path;
+ path_get(&file->f_path);
+ }
+ if (info)
+ snprintf(info, PROC_FDINFO_MAX,
+ "pos:\t%lli\n"
+ "flags:\t0%o\n",
+ (long long) file->f_pos,
+ f_flags);
+ spin_unlock(&files->file_lock);
+ put_files_struct(files);
+ return 0;
}
- if (info)
- snprintf(info, PROC_FDINFO_MAX,
- "pos:\t%lli\n"
- "flags:\t0%o\n",
- (long long) file->f_pos,
- f_flags);
- rc = 0;
- } else
- rc = -ENOENT;
- spin_unlock(&files->file_lock);
- put_files_struct(files);
-
-out_unlock:
- unlock_trace(task);
-out_task:
- put_task_struct(task);
- return rc;
+ spin_unlock(&files->file_lock);
+ put_files_struct(files);
+ }
+ return -ENOENT;
}
static int proc_fd_link(struct inode *inode, struct path *path)
@@ -2072,7 +2026,7 @@
spin_unlock(&files->file_lock);
put_files_struct(files);
- inode->i_op = &proc_fd_link_inode_operations;
+ inode->i_op = &proc_pid_link_inode_operations;
inode->i_size = 64;
ei->op.proc_get_link = proc_fd_link;
d_set_d_op(dentry, &tid_fd_dentry_operations);
@@ -2104,12 +2058,7 @@
if (fd == ~0U)
goto out;
- result = ERR_PTR(-EACCES);
- if (lock_trace(task))
- goto out;
-
result = instantiate(dir, dentry, task, &fd);
- unlock_trace(task);
out:
put_task_struct(task);
out_no_task:
@@ -2129,28 +2078,23 @@
retval = -ENOENT;
if (!p)
goto out_no_task;
-
- retval = -EACCES;
- if (lock_trace(p))
- goto out;
-
retval = 0;
fd = filp->f_pos;
switch (fd) {
case 0:
if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
- goto out_unlock;
+ goto out;
filp->f_pos++;
case 1:
ino = parent_ino(dentry);
if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
- goto out_unlock;
+ goto out;
filp->f_pos++;
default:
files = get_files_struct(p);
if (!files)
- goto out_unlock;
+ goto out;
rcu_read_lock();
for (fd = filp->f_pos-2;
fd < files_fdtable(files)->max_fds;
@@ -2174,9 +2118,6 @@
rcu_read_unlock();
put_files_struct(files);
}
-
-out_unlock:
- unlock_trace(p);
out:
put_task_struct(p);
out_no_task:
@@ -2254,7 +2195,6 @@
ei->fd = fd;
inode->i_mode = S_IFREG | S_IRUSR;
inode->i_fop = &proc_fdinfo_file_operations;
- inode->i_op = &proc_fdinfo_link_inode_operations;
d_set_d_op(dentry, &tid_fd_dentry_operations);
d_add(dentry, inode);
/* Close the race of the process dying before we return the dentry */
