[PATCH 5.8 10/70] io_uring: reference ->nsproxy for file table commands

Greg Kroah-Hartman
2020-10-31T11:40:20Z

From: Jens Axboe <axboe@kernel.dk>

commit 9b8284921513fc1ea57d87777283a59b05862f03 upstream.

If we don't get and assign the namespace for the async work, then certain
paths just don't work properly (like /dev/stdin, /proc/mounts, etc).
Anything that references the current namespace of the given task should
be assigned for async work on behalf of that task.

Cc: stable@vger.kernel.org # v5.5+
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/io-wq.c | 4 ++++
fs/io-wq.h | 1 +
fs/io_uring.c | 3 +++
3 files changed, 8 insertions(+)

--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -60,6 +60,7 @@ struct io_worker {
const struct cred *cur_creds;
const struct cred *saved_creds;
struct files_struct *restore_files;
+ struct nsproxy *restore_nsproxy;
struct fs_struct *restore_fs;
};

@@ -153,6 +154,7 @@ static bool __io_worker_unuse(struct io_

task_lock(current);
current->files = worker->restore_files;
+ current->nsproxy = worker->restore_nsproxy;
task_unlock(current);
}

@@ -318,6 +320,7 @@ static void io_worker_start(struct io_wq

worker->flags |= (IO_WORKER_F_UP | IO_WORKER_F_RUNNING);
worker->restore_files = current->files;
+ worker->restore_nsproxy = current->nsproxy;
worker->restore_fs = current->fs;
io_wqe_inc_running(wqe, worker);
}
@@ -454,6 +457,7 @@ static void io_impersonate_work(struct i
if (work->files && current->files != work->files) {
task_lock(current);
current->files = work->files;
+ current->nsproxy = work->nsproxy;
task_unlock(current);
}
if (work->fs && current->fs != work->fs)
--- a/fs/io-wq.h
+++ b/fs/io-wq.h
@@ -88,6 +88,7 @@ struct io_wq_work {
struct files_struct *files;
struct mm_struct *mm;
const struct cred *creds;
+ struct nsproxy *nsproxy;
struct fs_struct *fs;
unsigned flags;
};
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1456,6 +1456,7 @@ static void io_req_drop_files(struct io_
spin_unlock_irqrestore(&ctx->inflight_lock, flags);
req->flags &= ~REQ_F_INFLIGHT;
put_files_struct(req->work.files);
+ put_nsproxy(req->work.nsproxy);
req->work.files = NULL;
}

@@ -5685,6 +5686,8 @@ static int io_grab_files(struct io_kiocb
return 0;

req->work.files = get_files_struct(current);
+ get_nsproxy(current->nsproxy);
+ req->work.nsproxy = current->nsproxy;
req->flags |= REQ_F_INFLIGHT;

spin_lock_irq(&ctx->inflight_lock);