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io_uring: async workers should inherit the user creds

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If we don't inherit the original task creds, then we can confuse users
like fuse that pass creds in the request header. See link below on
identical aio issue.

Link: https://lore.kernel.org/linux-fsdevel/26f0d78e-99ca-2f1b-78b9-433088053a61@scylladb.com/T/#u
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2019-11-25 08:52:30 -07:00
parent 576a347b7a
commit 181e448d87
3 changed files with 19 additions and 0 deletions
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10
fs/io-wq.c
View File

@ -57,6 +57,7 @@ struct io_worker {
struct rcu_head rcu;
struct mm_struct *mm;
const struct cred *creds;
struct files_struct *restore_files;
};
@ -111,6 +112,7 @@ struct io_wq {
struct task_struct *manager;
struct user_struct *user;
struct cred *creds;
struct mm_struct *mm;
refcount_t refs;
struct completion done;
@ -136,6 +138,11 @@ static bool __io_worker_unuse(struct io_wqe *wqe, struct io_worker *worker)
{
bool dropped_lock = false;
if (worker->creds) {
revert_creds(worker->creds);
worker->creds = NULL;
}
if (current->files != worker->restore_files) {
__acquire(&wqe->lock);
spin_unlock_irq(&wqe->lock);
@ -442,6 +449,8 @@ next:
set_fs(USER_DS);
worker->mm = wq->mm;
}
if (!worker->creds)
worker->creds = override_creds(wq->creds);
if (test_bit(IO_WQ_BIT_CANCEL, &wq->state))
work->flags |= IO_WQ_WORK_CANCEL;
if (worker->mm)
@ -995,6 +1004,7 @@ struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
/* caller must already hold a reference to this */
wq->user = data->user;
wq->creds = data->creds;
i = 0;
for_each_online_node(node) {

1
fs/io-wq.h
View File

@ -45,6 +45,7 @@ typedef void (put_work_fn)(struct io_wq_work *);
struct io_wq_data {
struct mm_struct *mm;
struct user_struct *user;
struct cred *creds;
get_work_fn *get_work;
put_work_fn *put_work;

8
fs/io_uring.c
View File

@ -237,6 +237,8 @@ struct io_ring_ctx {
struct user_struct *user;
struct cred *creds;
/* 0 is for ctx quiesce/reinit/free, 1 is for sqo_thread started */
struct completion *completions;
@ -3267,6 +3269,7 @@ static int io_sq_thread(void *data)
{
struct io_ring_ctx *ctx = data;
struct mm_struct *cur_mm = NULL;
const struct cred *old_cred;
mm_segment_t old_fs;
DEFINE_WAIT(wait);
unsigned inflight;
@ -3277,6 +3280,7 @@ static int io_sq_thread(void *data)
old_fs = get_fs();
set_fs(USER_DS);
old_cred = override_creds(ctx->creds);
ret = timeout = inflight = 0;
while (!kthread_should_park()) {
@ -3383,6 +3387,7 @@ static int io_sq_thread(void *data)
unuse_mm(cur_mm);
mmput(cur_mm);
}
revert_creds(old_cred);
kthread_parkme();
@ -4009,6 +4014,7 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx,
data.mm = ctx->sqo_mm;
data.user = ctx->user;
data.creds = ctx->creds;
data.get_work = io_get_work;
data.put_work = io_put_work;
@ -4363,6 +4369,7 @@ static void io_ring_ctx_free(struct io_ring_ctx *ctx)
io_unaccount_mem(ctx->user,
ring_pages(ctx->sq_entries, ctx->cq_entries));
free_uid(ctx->user);
put_cred(ctx->creds);
kfree(ctx->completions);
kmem_cache_free(req_cachep, ctx->fallback_req);
kfree(ctx);
@ -4715,6 +4722,7 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p)
ctx->compat = in_compat_syscall();
ctx->account_mem = account_mem;
ctx->user = user;
ctx->creds = prepare_creds();
ret = io_allocate_scq_urings(ctx, p);
if (ret)