1// SPDX-License-Identifier: GPL-2.0
2#include <linux/kernel.h>
3#include <linux/errno.h>
4#include <linux/file.h>
5#include <linux/mm.h>
6#include <linux/slab.h>
7#include <linux/nospec.h>
8#include <linux/io_uring.h>
9
10#include <uapi/linux/io_uring.h>
11
12#include "io_uring.h"
13#include "rsrc.h"
14#include "filetable.h"
15
16static int io_file_bitmap_get(struct io_ring_ctx *ctx)
17{
18 struct io_file_table *table = &ctx->file_table;
19 unsigned long nr = ctx->file_alloc_end;
20 int ret;
21
22 if (!table->bitmap)
23 return -ENFILE;
24
25 do {
26 ret = find_next_zero_bit(addr: table->bitmap, size: nr, offset: table->alloc_hint);
27 if (ret != nr)
28 return ret;
29
30 if (table->alloc_hint == ctx->file_alloc_start)
31 break;
32 nr = table->alloc_hint;
33 table->alloc_hint = ctx->file_alloc_start;
34 } while (1);
35
36 return -ENFILE;
37}
38
39bool io_alloc_file_tables(struct io_ring_ctx *ctx, struct io_file_table *table,
40 unsigned nr_files)
41{
42 if (io_rsrc_data_alloc(data: &table->data, nr: nr_files))
43 return false;
44 table->bitmap = bitmap_zalloc(nbits: nr_files, GFP_KERNEL_ACCOUNT);
45 if (table->bitmap)
46 return true;
47 io_rsrc_data_free(ctx, data: &table->data);
48 return false;
49}
50
51void io_free_file_tables(struct io_ring_ctx *ctx, struct io_file_table *table)
52{
53 io_rsrc_data_free(ctx, data: &table->data);
54 bitmap_free(bitmap: table->bitmap);
55 table->bitmap = NULL;
56}
57
58static int io_install_fixed_file(struct io_ring_ctx *ctx, struct file *file,
59 u32 slot_index)
60 __must_hold(&req->ctx->uring_lock)
61{
62 struct io_rsrc_node *node;
63
64 if (io_is_uring_fops(file))
65 return -EBADF;
66 if (!ctx->file_table.data.nr)
67 return -ENXIO;
68 if (slot_index >= ctx->file_table.data.nr)
69 return -EINVAL;
70
71 node = io_rsrc_node_alloc(ctx, type: IORING_RSRC_FILE);
72 if (!node)
73 return -ENOMEM;
74
75 if (!io_reset_rsrc_node(ctx, data: &ctx->file_table.data, index: slot_index))
76 io_file_bitmap_set(table: &ctx->file_table, bit: slot_index);
77
78 ctx->file_table.data.nodes[slot_index] = node;
79 io_fixed_file_set(node, file);
80 return 0;
81}
82
83int __io_fixed_fd_install(struct io_ring_ctx *ctx, struct file *file,
84 unsigned int file_slot)
85{
86 bool alloc_slot = file_slot == IORING_FILE_INDEX_ALLOC;
87 int ret;
88
89 if (alloc_slot) {
90 ret = io_file_bitmap_get(ctx);
91 if (unlikely(ret < 0))
92 return ret;
93 file_slot = ret;
94 } else {
95 file_slot--;
96 }
97
98 ret = io_install_fixed_file(ctx, file, slot_index: file_slot);
99 if (!ret && alloc_slot)
100 ret = file_slot;
101 return ret;
102}
103/*
104 * Note when io_fixed_fd_install() returns error value, it will ensure
105 * fput() is called correspondingly.
106 */
107int io_fixed_fd_install(struct io_kiocb *req, unsigned int issue_flags,
108 struct file *file, unsigned int file_slot)
109{
110 struct io_ring_ctx *ctx = req->ctx;
111 int ret;
112
113 io_ring_submit_lock(ctx, issue_flags);
114 ret = __io_fixed_fd_install(ctx, file, file_slot);
115 io_ring_submit_unlock(ctx, issue_flags);
116
117 if (unlikely(ret < 0))
118 fput(file);
119 return ret;
120}
121
122int io_fixed_fd_remove(struct io_ring_ctx *ctx, unsigned int offset)
123{
124 struct io_rsrc_node *node;
125
126 if (unlikely(!ctx->file_table.data.nr))
127 return -ENXIO;
128 if (offset >= ctx->file_table.data.nr)
129 return -EINVAL;
130
131 node = io_rsrc_node_lookup(data: &ctx->file_table.data, index: offset);
132 if (!node)
133 return -EBADF;
134 io_reset_rsrc_node(ctx, data: &ctx->file_table.data, index: offset);
135 io_file_bitmap_clear(table: &ctx->file_table, bit: offset);
136 return 0;
137}
138
139int io_register_file_alloc_range(struct io_ring_ctx *ctx,
140 struct io_uring_file_index_range __user *arg)
141{
142 struct io_uring_file_index_range range;
143 u32 end;
144
145 if (copy_from_user(to: &range, from: arg, n: sizeof(range)))
146 return -EFAULT;
147 if (check_add_overflow(range.off, range.len, &end))
148 return -EOVERFLOW;
149 if (range.resv || end > ctx->file_table.data.nr)
150 return -EINVAL;
151
152 io_file_table_set_alloc_range(ctx, off: range.off, len: range.len);
153 return 0;
154}
155