Merge tag 'io_uring-5.18-2022-04-14' of git://git.kernel.dk/linux-block

Pull io_uring fixes from Jens Axboe:

 - Ensure we check and -EINVAL any use of reserved or struct padding.

   Although we generally always do that, it's missed in two spots for
   resource updates, one for the ring fd registration from this merge
   window, and one for the extended arg. Make sure we have all of them
   handled. (Dylan)

 - A few fixes for the deferred file assignment (me, Pavel)

 - Add a feature flag for the deferred file assignment so apps can tell
   we handle it correctly (me)

 - Fix a small perf regression with the current file position fix in
   this merge window (me)

* tag 'io_uring-5.18-2022-04-14' of git://git.kernel.dk/linux-block:
  io_uring: abort file assignment prior to assigning creds
  io_uring: fix poll error reporting
  io_uring: fix poll file assign deadlock
  io_uring: use right issue_flags for splice/tee
  io_uring: verify pad field is 0 in io_get_ext_arg
  io_uring: verify resv is 0 in ringfd register/unregister
  io_uring: verify that resv2 is 0 in io_uring_rsrc_update2
  io_uring: move io_uring_rsrc_update2 validation
  io_uring: fix assign file locking issue
  io_uring: stop using io_wq_work as an fd placeholder
  io_uring: move apoll->events cache
  io_uring: io_kiocb_update_pos() should not touch file for non -1 offset
  io_uring: flag the fact that linked file assignment is sane

3 files changed, 59 insertions, 41 deletions

diff --git a/fs/io-wq.h b/fs/io-wq.h
index 04d374e65e54..dbecd27656c7 100644
--- a/fs/io-wq.h
+++ b/fs/io-wq.h
@@ -155,7 +155,6 @@ struct io_wq_work_node *wq_stack_extract(struct io_wq_work_node *stack)
 struct io_wq_work {
 	struct io_wq_work_node list;
 	unsigned flags;
-	int fd;
 };
 
 static inline struct io_wq_work *wq_next_work(struct io_wq_work *work)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 659f8ecba5b7..4479013854d2 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -907,7 +907,11 @@ struct io_kiocb {
 
 	u64				user_data;
 	u32				result;
-	u32				cflags;
+	/* fd initially, then cflags for completion */
+	union {
+		u32			cflags;
+		int			fd;
+	};
 
 	struct io_ring_ctx		*ctx;
 	struct task_struct		*task;
@@ -916,8 +920,12 @@ struct io_kiocb {
 	/* store used ubuf, so we can prevent reloading */
 	struct io_mapped_ubuf		*imu;
 
-	/* used by request caches, completion batching and iopoll */
-	struct io_wq_work_node		comp_list;
+	union {
+		/* used by request caches, completion batching and iopoll */
+		struct io_wq_work_node	comp_list;
+		/* cache ->apoll->events */
+		int apoll_events;
+	};
 	atomic_t			refs;
 	atomic_t			poll_refs;
 	struct io_task_work		io_task_work;
@@ -3183,19 +3191,18 @@ static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
 static inline loff_t *io_kiocb_update_pos(struct io_kiocb *req)
 {
 	struct kiocb *kiocb = &req->rw.kiocb;
-	bool is_stream = req->file->f_mode & FMODE_STREAM;
 
-	if (kiocb->ki_pos == -1) {
-		if (!is_stream) {
-			req->flags |= REQ_F_CUR_POS;
-			kiocb->ki_pos = req->file->f_pos;
-			return &kiocb->ki_pos;
-		} else {
-			kiocb->ki_pos = 0;
-			return NULL;
-		}
+	if (kiocb->ki_pos != -1)
+		return &kiocb->ki_pos;
+
+	if (!(req->file->f_mode & FMODE_STREAM)) {
+		req->flags |= REQ_F_CUR_POS;
+		kiocb->ki_pos = req->file->f_pos;
+		return &kiocb->ki_pos;
 	}
-	return is_stream ? NULL : &kiocb->ki_pos;
+
+	kiocb->ki_pos = 0;
+	return NULL;
 }
 
 static void kiocb_done(struct io_kiocb *req, ssize_t ret,
@@ -4351,7 +4358,7 @@ static int io_tee(struct io_kiocb *req, unsigned int issue_flags)
 		return -EAGAIN;
 
 	if (sp->flags & SPLICE_F_FD_IN_FIXED)
-		in = io_file_get_fixed(req, sp->splice_fd_in, IO_URING_F_UNLOCKED);
+		in = io_file_get_fixed(req, sp->splice_fd_in, issue_flags);
 	else
 		in = io_file_get_normal(req, sp->splice_fd_in);
 	if (!in) {
@@ -4393,7 +4400,7 @@ static int io_splice(struct io_kiocb *req, unsigned int issue_flags)
 		return -EAGAIN;
 
 	if (sp->flags & SPLICE_F_FD_IN_FIXED)
-		in = io_file_get_fixed(req, sp->splice_fd_in, IO_URING_F_UNLOCKED);
+		in = io_file_get_fixed(req, sp->splice_fd_in, issue_flags);
 	else
 		in = io_file_get_normal(req, sp->splice_fd_in);
 	if (!in) {
@@ -5834,7 +5841,6 @@ static void io_poll_remove_entries(struct io_kiocb *req)
 static int io_poll_check_events(struct io_kiocb *req, bool locked)
 {
 	struct io_ring_ctx *ctx = req->ctx;
-	struct io_poll_iocb *poll = io_poll_get_single(req);
 	int v;
 
 	/* req->task == current here, checking PF_EXITING is safe */
@@ -5851,17 +5857,17 @@ static int io_poll_check_events(struct io_kiocb *req, bool locked)
 			return -ECANCELED;
 
 		if (!req->result) {
-			struct poll_table_struct pt = { ._key = req->cflags };
+			struct poll_table_struct pt = { ._key = req->apoll_events };
+			unsigned flags = locked ? 0 : IO_URING_F_UNLOCKED;
 
-			if (unlikely(!io_assign_file(req, IO_URING_F_UNLOCKED)))
-				req->result = -EBADF;
-			else
-				req->result = vfs_poll(req->file, &pt) & req->cflags;
+			if (unlikely(!io_assign_file(req, flags)))
+				return -EBADF;
+			req->result = vfs_poll(req->file, &pt) & req->apoll_events;
 		}
 
 		/* multishot, just fill an CQE and proceed */
-		if (req->result && !(req->cflags & EPOLLONESHOT)) {
-			__poll_t mask = mangle_poll(req->result & poll->events);
+		if (req->result && !(req->apoll_events & EPOLLONESHOT)) {
+			__poll_t mask = mangle_poll(req->result & req->apoll_events);
 			bool filled;
 
 			spin_lock(&ctx->completion_lock);
@@ -5939,7 +5945,7 @@ static void __io_poll_execute(struct io_kiocb *req, int mask, int events)
 	 * CPU. We want to avoid pulling in req->apoll->events for that
 	 * case.
 	 */
-	req->cflags = events;
+	req->apoll_events = events;
 	if (req->opcode == IORING_OP_POLL_ADD)
 		req->io_task_work.func = io_poll_task_func;
 	else
@@ -6331,7 +6337,7 @@ static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe
 		return -EINVAL;
 
 	io_req_set_refcount(req);
-	req->cflags = poll->events = io_poll_parse_events(sqe, flags);
+	req->apoll_events = poll->events = io_poll_parse_events(sqe, flags);
 	return 0;
 }
 
@@ -6833,6 +6839,7 @@ static int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
 	up.nr = 0;
 	up.tags = 0;
 	up.resv = 0;
+	up.resv2 = 0;
 
 	io_ring_submit_lock(ctx, needs_lock);
 	ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE,
@@ -7088,9 +7095,9 @@ static bool io_assign_file(struct io_kiocb *req, unsigned int issue_flags)
 		return true;
 
 	if (req->flags & REQ_F_FIXED_FILE)
-		req->file = io_file_get_fixed(req, req->work.fd, issue_flags);
+		req->file = io_file_get_fixed(req, req->fd, issue_flags);
 	else
-		req->file = io_file_get_normal(req, req->work.fd);
+		req->file = io_file_get_normal(req, req->fd);
 	if (req->file)
 		return true;
 
@@ -7104,13 +7111,14 @@ static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
 	const struct cred *creds = NULL;
 	int ret;
 
+	if (unlikely(!io_assign_file(req, issue_flags)))
+		return -EBADF;
+
 	if (unlikely((req->flags & REQ_F_CREDS) && req->creds != current_cred()))
 		creds = override_creds(req->creds);
 
 	if (!io_op_defs[req->opcode].audit_skip)
 		audit_uring_entry(req->opcode);
-	if (unlikely(!io_assign_file(req, issue_flags)))
-		return -EBADF;
 
 	switch (req->opcode) {
 	case IORING_OP_NOP:
@@ -7271,16 +7279,18 @@ static void io_wq_submit_work(struct io_wq_work *work)
 	if (timeout)
 		io_queue_linked_timeout(timeout);
 
-	if (!io_assign_file(req, issue_flags)) {
-		err = -EBADF;
-		work->flags |= IO_WQ_WORK_CANCEL;
-	}
 
 	/* either cancelled or io-wq is dying, so don't touch tctx->iowq */
 	if (work->flags & IO_WQ_WORK_CANCEL) {
+fail:
 		io_req_task_queue_fail(req, err);
 		return;
 	}
+	if (!io_assign_file(req, issue_flags)) {
+		err = -EBADF;
+		work->flags |= IO_WQ_WORK_CANCEL;
+		goto fail;
+	}
 
 	if (req->flags & REQ_F_FORCE_ASYNC) {
 		bool opcode_poll = def->pollin || def->pollout;
@@ -7628,7 +7638,7 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
 	if (io_op_defs[opcode].needs_file) {
 		struct io_submit_state *state = &ctx->submit_state;
 
-		req->work.fd = READ_ONCE(sqe->fd);
+		req->fd = READ_ONCE(sqe->fd);
 
 		/*
 		 * Plug now if we have more than 2 IO left after this, and the
@@ -10524,6 +10534,11 @@ static int io_ringfd_register(struct io_ring_ctx *ctx, void __user *__arg,
 			break;
 		}
 
+		if (reg.resv) {
+			ret = -EINVAL;
+			break;
+		}
+
 		if (reg.offset == -1U) {
 			start = 0;
 			end = IO_RINGFD_REG_MAX;
@@ -10570,7 +10585,7 @@ static int io_ringfd_unregister(struct io_ring_ctx *ctx, void __user *__arg,
 			ret = -EFAULT;
 			break;
 		}
-		if (reg.offset >= IO_RINGFD_REG_MAX) {
+		if (reg.resv || reg.offset >= IO_RINGFD_REG_MAX) {
 			ret = -EINVAL;
 			break;
 		}
@@ -10697,6 +10712,8 @@ static int io_get_ext_arg(unsigned flags, const void __user *argp, size_t *argsz
 		return -EINVAL;
 	if (copy_from_user(&arg, argp, sizeof(arg)))
 		return -EFAULT;
+	if (arg.pad)
+		return -EINVAL;
 	*sig = u64_to_user_ptr(arg.sigmask);
 	*argsz = arg.sigmask_sz;
 	*ts = u64_to_user_ptr(arg.ts);
@@ -11178,7 +11195,8 @@ static __cold int io_uring_create(unsigned entries, struct io_uring_params *p,
 			IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL |
 			IORING_FEAT_POLL_32BITS | IORING_FEAT_SQPOLL_NONFIXED |
 			IORING_FEAT_EXT_ARG | IORING_FEAT_NATIVE_WORKERS |
-			IORING_FEAT_RSRC_TAGS | IORING_FEAT_CQE_SKIP;
+			IORING_FEAT_RSRC_TAGS | IORING_FEAT_CQE_SKIP |
+			IORING_FEAT_LINKED_FILE;
 
 	if (copy_to_user(params, p, sizeof(*p))) {
 		ret = -EFAULT;
@@ -11389,8 +11407,6 @@ static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
 	__u32 tmp;
 	int err;
 
-	if (up->resv)
-		return -EINVAL;
 	if (check_add_overflow(up->offset, nr_args, &tmp))
 		return -EOVERFLOW;
 	err = io_rsrc_node_switch_start(ctx);
@@ -11416,6 +11432,8 @@ static int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg,
 	memset(&up, 0, sizeof(up));
 	if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update)))
 		return -EFAULT;
+	if (up.resv || up.resv2)
+		return -EINVAL;
 	return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args);
 }
 
@@ -11428,7 +11446,7 @@ static int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg,
 		return -EINVAL;
 	if (copy_from_user(&up, arg, sizeof(up)))
 		return -EFAULT;
-	if (!up.nr || up.resv)
+	if (!up.nr || up.resv || up.resv2)
 		return -EINVAL;
 	return __io_register_rsrc_update(ctx, type, &up, up.nr);
 }
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 784adc6f6ed2..1845cf7c80ba 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -296,6 +296,7 @@ struct io_uring_params {
 #define IORING_FEAT_NATIVE_WORKERS	(1U << 9)
 #define IORING_FEAT_RSRC_TAGS		(1U << 10)
 #define IORING_FEAT_CQE_SKIP		(1U << 11)
+#define IORING_FEAT_LINKED_FILE		(1U << 12)
 
 /*
  * io_uring_register(2) opcodes and arguments