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 16 static 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(table->bitmap, nr, 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 39 bool io_alloc_file_tables(struct io_file_table *table, unsigned nr_files) 40 { 41 table->files = kvcalloc(nr_files, sizeof(table->files[0]), 42 GFP_KERNEL_ACCOUNT); 43 if (unlikely(!table->files)) 44 return false; 45 46 table->bitmap = bitmap_zalloc(nr_files, GFP_KERNEL_ACCOUNT); 47 if (unlikely(!table->bitmap)) { 48 kvfree(table->files); 49 return false; 50 } 51 52 return true; 53 } 54 55 void io_free_file_tables(struct io_file_table *table) 56 { 57 kvfree(table->files); 58 bitmap_free(table->bitmap); 59 table->files = NULL; 60 table->bitmap = NULL; 61 } 62 63 static int io_install_fixed_file(struct io_ring_ctx *ctx, struct file *file, 64 u32 slot_index) 65 __must_hold(&req->ctx->uring_lock) 66 { 67 bool needs_switch = false; 68 struct io_fixed_file *file_slot; 69 int ret; 70 71 if (io_is_uring_fops(file)) 72 return -EBADF; 73 if (!ctx->file_data) 74 return -ENXIO; 75 if (slot_index >= ctx->nr_user_files) 76 return -EINVAL; 77 78 slot_index = array_index_nospec(slot_index, ctx->nr_user_files); 79 file_slot = io_fixed_file_slot(&ctx->file_table, slot_index); 80 81 if (file_slot->file_ptr) { 82 struct file *old_file; 83 84 ret = io_rsrc_node_switch_start(ctx); 85 if (ret) 86 goto err; 87 88 old_file = (struct file *)(file_slot->file_ptr & FFS_MASK); 89 ret = io_queue_rsrc_removal(ctx->file_data, slot_index, 90 ctx->rsrc_node, old_file); 91 if (ret) 92 goto err; 93 file_slot->file_ptr = 0; 94 io_file_bitmap_clear(&ctx->file_table, slot_index); 95 needs_switch = true; 96 } 97 98 ret = io_scm_file_account(ctx, file); 99 if (!ret) { 100 *io_get_tag_slot(ctx->file_data, slot_index) = 0; 101 io_fixed_file_set(file_slot, file); 102 io_file_bitmap_set(&ctx->file_table, slot_index); 103 } 104 err: 105 if (needs_switch) 106 io_rsrc_node_switch(ctx, ctx->file_data); 107 return ret; 108 } 109 110 int __io_fixed_fd_install(struct io_ring_ctx *ctx, struct file *file, 111 unsigned int file_slot) 112 { 113 bool alloc_slot = file_slot == IORING_FILE_INDEX_ALLOC; 114 int ret; 115 116 if (alloc_slot) { 117 ret = io_file_bitmap_get(ctx); 118 if (unlikely(ret < 0)) 119 return ret; 120 file_slot = ret; 121 } else { 122 file_slot--; 123 } 124 125 ret = io_install_fixed_file(ctx, file, file_slot); 126 if (!ret && alloc_slot) 127 ret = file_slot; 128 return ret; 129 } 130 /* 131 * Note when io_fixed_fd_install() returns error value, it will ensure 132 * fput() is called correspondingly. 133 */ 134 int io_fixed_fd_install(struct io_kiocb *req, unsigned int issue_flags, 135 struct file *file, unsigned int file_slot) 136 { 137 struct io_ring_ctx *ctx = req->ctx; 138 int ret; 139 140 io_ring_submit_lock(ctx, issue_flags); 141 ret = __io_fixed_fd_install(ctx, file, file_slot); 142 io_ring_submit_unlock(ctx, issue_flags); 143 144 if (unlikely(ret < 0)) 145 fput(file); 146 return ret; 147 } 148 149 int io_fixed_fd_remove(struct io_ring_ctx *ctx, unsigned int offset) 150 { 151 struct io_fixed_file *file_slot; 152 struct file *file; 153 int ret; 154 155 if (unlikely(!ctx->file_data)) 156 return -ENXIO; 157 if (offset >= ctx->nr_user_files) 158 return -EINVAL; 159 ret = io_rsrc_node_switch_start(ctx); 160 if (ret) 161 return ret; 162 163 offset = array_index_nospec(offset, ctx->nr_user_files); 164 file_slot = io_fixed_file_slot(&ctx->file_table, offset); 165 if (!file_slot->file_ptr) 166 return -EBADF; 167 168 file = (struct file *)(file_slot->file_ptr & FFS_MASK); 169 ret = io_queue_rsrc_removal(ctx->file_data, offset, ctx->rsrc_node, file); 170 if (ret) 171 return ret; 172 173 file_slot->file_ptr = 0; 174 io_file_bitmap_clear(&ctx->file_table, offset); 175 io_rsrc_node_switch(ctx, ctx->file_data); 176 return 0; 177 } 178 179 int io_register_file_alloc_range(struct io_ring_ctx *ctx, 180 struct io_uring_file_index_range __user *arg) 181 { 182 struct io_uring_file_index_range range; 183 u32 end; 184 185 if (copy_from_user(&range, arg, sizeof(range))) 186 return -EFAULT; 187 if (check_add_overflow(range.off, range.len, &end)) 188 return -EOVERFLOW; 189 if (range.resv || end > ctx->nr_user_files) 190 return -EINVAL; 191 192 io_file_table_set_alloc_range(ctx, range.off, range.len); 193 return 0; 194 } 195