| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Code related to the io_uring_register() syscall |
| * |
| * Copyright (C) 2023 Jens Axboe |
| */ |
| #include <linux/kernel.h> |
| #include <linux/errno.h> |
| #include <linux/syscalls.h> |
| #include <linux/refcount.h> |
| #include <linux/bits.h> |
| #include <linux/fs.h> |
| #include <linux/file.h> |
| #include <linux/slab.h> |
| #include <linux/uaccess.h> |
| #include <linux/nospec.h> |
| #include <linux/compat.h> |
| #include <linux/io_uring.h> |
| #include <linux/io_uring_types.h> |
| |
| #include "io_uring.h" |
| #include "opdef.h" |
| #include "tctx.h" |
| #include "rsrc.h" |
| #include "sqpoll.h" |
| #include "register.h" |
| #include "cancel.h" |
| #include "kbuf.h" |
| #include "napi.h" |
| #include "eventfd.h" |
| |
| #define IORING_MAX_RESTRICTIONS (IORING_RESTRICTION_LAST + \ |
| IORING_REGISTER_LAST + IORING_OP_LAST) |
| |
| static __cold int io_probe(struct io_ring_ctx *ctx, void __user *arg, |
| unsigned nr_args) |
| { |
| struct io_uring_probe *p; |
| size_t size; |
| int i, ret; |
| |
| if (nr_args > IORING_OP_LAST) |
| nr_args = IORING_OP_LAST; |
| |
| size = struct_size(p, ops, nr_args); |
| p = kzalloc(size, GFP_KERNEL); |
| if (!p) |
| return -ENOMEM; |
| |
| ret = -EFAULT; |
| if (copy_from_user(p, arg, size)) |
| goto out; |
| ret = -EINVAL; |
| if (memchr_inv(p, 0, size)) |
| goto out; |
| |
| p->last_op = IORING_OP_LAST - 1; |
| |
| for (i = 0; i < nr_args; i++) { |
| p->ops[i].op = i; |
| if (io_uring_op_supported(i)) |
| p->ops[i].flags = IO_URING_OP_SUPPORTED; |
| } |
| p->ops_len = i; |
| |
| ret = 0; |
| if (copy_to_user(arg, p, size)) |
| ret = -EFAULT; |
| out: |
| kfree(p); |
| return ret; |
| } |
| |
| int io_unregister_personality(struct io_ring_ctx *ctx, unsigned id) |
| { |
| const struct cred *creds; |
| |
| creds = xa_erase(&ctx->personalities, id); |
| if (creds) { |
| put_cred(creds); |
| return 0; |
| } |
| |
| return -EINVAL; |
| } |
| |
| |
| static int io_register_personality(struct io_ring_ctx *ctx) |
| { |
| const struct cred *creds; |
| u32 id; |
| int ret; |
| |
| creds = get_current_cred(); |
| |
| ret = xa_alloc_cyclic(&ctx->personalities, &id, (void *)creds, |
| XA_LIMIT(0, USHRT_MAX), &ctx->pers_next, GFP_KERNEL); |
| if (ret < 0) { |
| put_cred(creds); |
| return ret; |
| } |
| return id; |
| } |
| |
| static __cold int io_register_restrictions(struct io_ring_ctx *ctx, |
| void __user *arg, unsigned int nr_args) |
| { |
| struct io_uring_restriction *res; |
| size_t size; |
| int i, ret; |
| |
| /* Restrictions allowed only if rings started disabled */ |
| if (!(ctx->flags & IORING_SETUP_R_DISABLED)) |
| return -EBADFD; |
| |
| /* We allow only a single restrictions registration */ |
| if (ctx->restrictions.registered) |
| return -EBUSY; |
| |
| if (!arg || nr_args > IORING_MAX_RESTRICTIONS) |
| return -EINVAL; |
| |
| size = array_size(nr_args, sizeof(*res)); |
| if (size == SIZE_MAX) |
| return -EOVERFLOW; |
| |
| res = memdup_user(arg, size); |
| if (IS_ERR(res)) |
| return PTR_ERR(res); |
| |
| ret = 0; |
| |
| for (i = 0; i < nr_args; i++) { |
| switch (res[i].opcode) { |
| case IORING_RESTRICTION_REGISTER_OP: |
| if (res[i].register_op >= IORING_REGISTER_LAST) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| __set_bit(res[i].register_op, |
| ctx->restrictions.register_op); |
| break; |
| case IORING_RESTRICTION_SQE_OP: |
| if (res[i].sqe_op >= IORING_OP_LAST) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| __set_bit(res[i].sqe_op, ctx->restrictions.sqe_op); |
| break; |
| case IORING_RESTRICTION_SQE_FLAGS_ALLOWED: |
| ctx->restrictions.sqe_flags_allowed = res[i].sqe_flags; |
| break; |
| case IORING_RESTRICTION_SQE_FLAGS_REQUIRED: |
| ctx->restrictions.sqe_flags_required = res[i].sqe_flags; |
| break; |
| default: |
| ret = -EINVAL; |
| goto out; |
| } |
| } |
| |
| out: |
| /* Reset all restrictions if an error happened */ |
| if (ret != 0) |
| memset(&ctx->restrictions, 0, sizeof(ctx->restrictions)); |
| else |
| ctx->restrictions.registered = true; |
| |
| kfree(res); |
| return ret; |
| } |
| |
| static int io_register_enable_rings(struct io_ring_ctx *ctx) |
| { |
| if (!(ctx->flags & IORING_SETUP_R_DISABLED)) |
| return -EBADFD; |
| |
| if (ctx->flags & IORING_SETUP_SINGLE_ISSUER && !ctx->submitter_task) { |
| WRITE_ONCE(ctx->submitter_task, get_task_struct(current)); |
| /* |
| * Lazy activation attempts would fail if it was polled before |
| * submitter_task is set. |
| */ |
| if (wq_has_sleeper(&ctx->poll_wq)) |
| io_activate_pollwq(ctx); |
| } |
| |
| if (ctx->restrictions.registered) |
| ctx->restricted = 1; |
| |
| ctx->flags &= ~IORING_SETUP_R_DISABLED; |
| if (ctx->sq_data && wq_has_sleeper(&ctx->sq_data->wait)) |
| wake_up(&ctx->sq_data->wait); |
| return 0; |
| } |
| |
| static __cold int __io_register_iowq_aff(struct io_ring_ctx *ctx, |
| cpumask_var_t new_mask) |
| { |
| int ret; |
| |
| if (!(ctx->flags & IORING_SETUP_SQPOLL)) { |
| ret = io_wq_cpu_affinity(current->io_uring, new_mask); |
| } else { |
| mutex_unlock(&ctx->uring_lock); |
| ret = io_sqpoll_wq_cpu_affinity(ctx, new_mask); |
| mutex_lock(&ctx->uring_lock); |
| } |
| |
| return ret; |
| } |
| |
| static __cold int io_register_iowq_aff(struct io_ring_ctx *ctx, |
| void __user *arg, unsigned len) |
| { |
| cpumask_var_t new_mask; |
| int ret; |
| |
| if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) |
| return -ENOMEM; |
| |
| cpumask_clear(new_mask); |
| if (len > cpumask_size()) |
| len = cpumask_size(); |
| |
| #ifdef CONFIG_COMPAT |
| if (in_compat_syscall()) |
| ret = compat_get_bitmap(cpumask_bits(new_mask), |
| (const compat_ulong_t __user *)arg, |
| len * 8 /* CHAR_BIT */); |
| else |
| #endif |
| ret = copy_from_user(new_mask, arg, len); |
| |
| if (ret) { |
| free_cpumask_var(new_mask); |
| return -EFAULT; |
| } |
| |
| ret = __io_register_iowq_aff(ctx, new_mask); |
| free_cpumask_var(new_mask); |
| return ret; |
| } |
| |
| static __cold int io_unregister_iowq_aff(struct io_ring_ctx *ctx) |
| { |
| return __io_register_iowq_aff(ctx, NULL); |
| } |
| |
| static __cold int io_register_iowq_max_workers(struct io_ring_ctx *ctx, |
| void __user *arg) |
| __must_hold(&ctx->uring_lock) |
| { |
| struct io_tctx_node *node; |
| struct io_uring_task *tctx = NULL; |
| struct io_sq_data *sqd = NULL; |
| __u32 new_count[2]; |
| int i, ret; |
| |
| if (copy_from_user(new_count, arg, sizeof(new_count))) |
| return -EFAULT; |
| for (i = 0; i < ARRAY_SIZE(new_count); i++) |
| if (new_count[i] > INT_MAX) |
| return -EINVAL; |
| |
| if (ctx->flags & IORING_SETUP_SQPOLL) { |
| sqd = ctx->sq_data; |
| if (sqd) { |
| /* |
| * Observe the correct sqd->lock -> ctx->uring_lock |
| * ordering. Fine to drop uring_lock here, we hold |
| * a ref to the ctx. |
| */ |
| refcount_inc(&sqd->refs); |
| mutex_unlock(&ctx->uring_lock); |
| mutex_lock(&sqd->lock); |
| mutex_lock(&ctx->uring_lock); |
| if (sqd->thread) |
| tctx = sqd->thread->io_uring; |
| } |
| } else { |
| tctx = current->io_uring; |
| } |
| |
| BUILD_BUG_ON(sizeof(new_count) != sizeof(ctx->iowq_limits)); |
| |
| for (i = 0; i < ARRAY_SIZE(new_count); i++) |
| if (new_count[i]) |
| ctx->iowq_limits[i] = new_count[i]; |
| ctx->iowq_limits_set = true; |
| |
| if (tctx && tctx->io_wq) { |
| ret = io_wq_max_workers(tctx->io_wq, new_count); |
| if (ret) |
| goto err; |
| } else { |
| memset(new_count, 0, sizeof(new_count)); |
| } |
| |
| if (sqd) { |
| mutex_unlock(&ctx->uring_lock); |
| mutex_unlock(&sqd->lock); |
| io_put_sq_data(sqd); |
| mutex_lock(&ctx->uring_lock); |
| } |
| |
| if (copy_to_user(arg, new_count, sizeof(new_count))) |
| return -EFAULT; |
| |
| /* that's it for SQPOLL, only the SQPOLL task creates requests */ |
| if (sqd) |
| return 0; |
| |
| /* now propagate the restriction to all registered users */ |
| list_for_each_entry(node, &ctx->tctx_list, ctx_node) { |
| tctx = node->task->io_uring; |
| if (WARN_ON_ONCE(!tctx->io_wq)) |
| continue; |
| |
| for (i = 0; i < ARRAY_SIZE(new_count); i++) |
| new_count[i] = ctx->iowq_limits[i]; |
| /* ignore errors, it always returns zero anyway */ |
| (void)io_wq_max_workers(tctx->io_wq, new_count); |
| } |
| return 0; |
| err: |
| if (sqd) { |
| mutex_unlock(&ctx->uring_lock); |
| mutex_unlock(&sqd->lock); |
| io_put_sq_data(sqd); |
| mutex_lock(&ctx->uring_lock); |
| } |
| return ret; |
| } |
| |
| static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, |
| void __user *arg, unsigned nr_args) |
| __releases(ctx->uring_lock) |
| __acquires(ctx->uring_lock) |
| { |
| int ret; |
| |
| /* |
| * We don't quiesce the refs for register anymore and so it can't be |
| * dying as we're holding a file ref here. |
| */ |
| if (WARN_ON_ONCE(percpu_ref_is_dying(&ctx->refs))) |
| return -ENXIO; |
| |
| if (ctx->submitter_task && ctx->submitter_task != current) |
| return -EEXIST; |
| |
| if (ctx->restricted) { |
| opcode = array_index_nospec(opcode, IORING_REGISTER_LAST); |
| if (!test_bit(opcode, ctx->restrictions.register_op)) |
| return -EACCES; |
| } |
| |
| switch (opcode) { |
| case IORING_REGISTER_BUFFERS: |
| ret = -EFAULT; |
| if (!arg) |
| break; |
| ret = io_sqe_buffers_register(ctx, arg, nr_args, NULL); |
| break; |
| case IORING_UNREGISTER_BUFFERS: |
| ret = -EINVAL; |
| if (arg || nr_args) |
| break; |
| ret = io_sqe_buffers_unregister(ctx); |
| break; |
| case IORING_REGISTER_FILES: |
| ret = -EFAULT; |
| if (!arg) |
| break; |
| ret = io_sqe_files_register(ctx, arg, nr_args, NULL); |
| break; |
| case IORING_UNREGISTER_FILES: |
| ret = -EINVAL; |
| if (arg || nr_args) |
| break; |
| ret = io_sqe_files_unregister(ctx); |
| break; |
| case IORING_REGISTER_FILES_UPDATE: |
| ret = io_register_files_update(ctx, arg, nr_args); |
| break; |
| case IORING_REGISTER_EVENTFD: |
| ret = -EINVAL; |
| if (nr_args != 1) |
| break; |
| ret = io_eventfd_register(ctx, arg, 0); |
| break; |
| case IORING_REGISTER_EVENTFD_ASYNC: |
| ret = -EINVAL; |
| if (nr_args != 1) |
| break; |
| ret = io_eventfd_register(ctx, arg, 1); |
| break; |
| case IORING_UNREGISTER_EVENTFD: |
| ret = -EINVAL; |
| if (arg || nr_args) |
| break; |
| ret = io_eventfd_unregister(ctx); |
| break; |
| case IORING_REGISTER_PROBE: |
| ret = -EINVAL; |
| if (!arg || nr_args > 256) |
| break; |
| ret = io_probe(ctx, arg, nr_args); |
| break; |
| case IORING_REGISTER_PERSONALITY: |
| ret = -EINVAL; |
| if (arg || nr_args) |
| break; |
| ret = io_register_personality(ctx); |
| break; |
| case IORING_UNREGISTER_PERSONALITY: |
| ret = -EINVAL; |
| if (arg) |
| break; |
| ret = io_unregister_personality(ctx, nr_args); |
| break; |
| case IORING_REGISTER_ENABLE_RINGS: |
| ret = -EINVAL; |
| if (arg || nr_args) |
| break; |
| ret = io_register_enable_rings(ctx); |
| break; |
| case IORING_REGISTER_RESTRICTIONS: |
| ret = io_register_restrictions(ctx, arg, nr_args); |
| break; |
| case IORING_REGISTER_FILES2: |
| ret = io_register_rsrc(ctx, arg, nr_args, IORING_RSRC_FILE); |
| break; |
| case IORING_REGISTER_FILES_UPDATE2: |
| ret = io_register_rsrc_update(ctx, arg, nr_args, |
| IORING_RSRC_FILE); |
| break; |
| case IORING_REGISTER_BUFFERS2: |
| ret = io_register_rsrc(ctx, arg, nr_args, IORING_RSRC_BUFFER); |
| break; |
| case IORING_REGISTER_BUFFERS_UPDATE: |
| ret = io_register_rsrc_update(ctx, arg, nr_args, |
| IORING_RSRC_BUFFER); |
| break; |
| case IORING_REGISTER_IOWQ_AFF: |
| ret = -EINVAL; |
| if (!arg || !nr_args) |
| break; |
| ret = io_register_iowq_aff(ctx, arg, nr_args); |
| break; |
| case IORING_UNREGISTER_IOWQ_AFF: |
| ret = -EINVAL; |
| if (arg || nr_args) |
| break; |
| ret = io_unregister_iowq_aff(ctx); |
| break; |
| case IORING_REGISTER_IOWQ_MAX_WORKERS: |
| ret = -EINVAL; |
| if (!arg || nr_args != 2) |
| break; |
| ret = io_register_iowq_max_workers(ctx, arg); |
| break; |
| case IORING_REGISTER_RING_FDS: |
| ret = io_ringfd_register(ctx, arg, nr_args); |
| break; |
| case IORING_UNREGISTER_RING_FDS: |
| ret = io_ringfd_unregister(ctx, arg, nr_args); |
| break; |
| case IORING_REGISTER_PBUF_RING: |
| ret = -EINVAL; |
| if (!arg || nr_args != 1) |
| break; |
| ret = io_register_pbuf_ring(ctx, arg); |
| break; |
| case IORING_UNREGISTER_PBUF_RING: |
| ret = -EINVAL; |
| if (!arg || nr_args != 1) |
| break; |
| ret = io_unregister_pbuf_ring(ctx, arg); |
| break; |
| case IORING_REGISTER_SYNC_CANCEL: |
| ret = -EINVAL; |
| if (!arg || nr_args != 1) |
| break; |
| ret = io_sync_cancel(ctx, arg); |
| break; |
| case IORING_REGISTER_FILE_ALLOC_RANGE: |
| ret = -EINVAL; |
| if (!arg || nr_args) |
| break; |
| ret = io_register_file_alloc_range(ctx, arg); |
| break; |
| case IORING_REGISTER_PBUF_STATUS: |
| ret = -EINVAL; |
| if (!arg || nr_args != 1) |
| break; |
| ret = io_register_pbuf_status(ctx, arg); |
| break; |
| case IORING_REGISTER_NAPI: |
| ret = -EINVAL; |
| if (!arg || nr_args != 1) |
| break; |
| ret = io_register_napi(ctx, arg); |
| break; |
| case IORING_UNREGISTER_NAPI: |
| ret = -EINVAL; |
| if (nr_args != 1) |
| break; |
| ret = io_unregister_napi(ctx, arg); |
| break; |
| default: |
| ret = -EINVAL; |
| break; |
| } |
| |
| return ret; |
| } |
| |
| SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode, |
| void __user *, arg, unsigned int, nr_args) |
| { |
| struct io_ring_ctx *ctx; |
| long ret = -EBADF; |
| struct file *file; |
| bool use_registered_ring; |
| |
| use_registered_ring = !!(opcode & IORING_REGISTER_USE_REGISTERED_RING); |
| opcode &= ~IORING_REGISTER_USE_REGISTERED_RING; |
| |
| if (opcode >= IORING_REGISTER_LAST) |
| return -EINVAL; |
| |
| if (use_registered_ring) { |
| /* |
| * Ring fd has been registered via IORING_REGISTER_RING_FDS, we |
| * need only dereference our task private array to find it. |
| */ |
| struct io_uring_task *tctx = current->io_uring; |
| |
| if (unlikely(!tctx || fd >= IO_RINGFD_REG_MAX)) |
| return -EINVAL; |
| fd = array_index_nospec(fd, IO_RINGFD_REG_MAX); |
| file = tctx->registered_rings[fd]; |
| if (unlikely(!file)) |
| return -EBADF; |
| } else { |
| file = fget(fd); |
| if (unlikely(!file)) |
| return -EBADF; |
| ret = -EOPNOTSUPP; |
| if (!io_is_uring_fops(file)) |
| goto out_fput; |
| } |
| |
| ctx = file->private_data; |
| |
| mutex_lock(&ctx->uring_lock); |
| ret = __io_uring_register(ctx, opcode, arg, nr_args); |
| mutex_unlock(&ctx->uring_lock); |
| trace_io_uring_register(ctx, opcode, ctx->nr_user_files, ctx->nr_user_bufs, ret); |
| out_fput: |
| if (!use_registered_ring) |
| fput(file); |
| return ret; |
| } |