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 struct io_fixed_file *file_slot; 68 int ret; 69 70 if (io_is_uring_fops(file)) 71 return -EBADF; 72 if (!ctx->file_data) 73 return -ENXIO; 74 if (slot_index >= ctx->nr_user_files) 75 return -EINVAL; 76 77 slot_index = array_index_nospec(slot_index, ctx->nr_user_files); 78 file_slot = io_fixed_file_slot(&ctx->file_table, slot_index); 79 80 if (file_slot->file_ptr) { 81 struct file *old_file; 82 83 old_file = (struct file *)(file_slot->file_ptr & FFS_MASK); 84 ret = io_queue_rsrc_removal(ctx->file_data, slot_index, old_file); 85 if (ret) 86 return ret; 87 88 file_slot->file_ptr = 0; 89 io_file_bitmap_clear(&ctx->file_table, slot_index); 90 } 91 92 ret = io_scm_file_account(ctx, file); 93 if (!ret) { 94 *io_get_tag_slot(ctx->file_data, slot_index) = 0; 95 io_fixed_file_set(file_slot, file); 96 io_file_bitmap_set(&ctx->file_table, slot_index); 97 } 98 return ret; 99 } 100 101 int __io_fixed_fd_install(struct io_ring_ctx *ctx, struct file *file, 102 unsigned int file_slot) 103 { 104 bool alloc_slot = file_slot == IORING_FILE_INDEX_ALLOC; 105 int ret; 106 107 if (alloc_slot) { 108 ret = io_file_bitmap_get(ctx); 109 if (unlikely(ret < 0)) 110 return ret; 111 file_slot = ret; 112 } else { 113 file_slot--; 114 } 115 116 ret = io_install_fixed_file(ctx, file, file_slot); 117 if (!ret && alloc_slot) 118 ret = file_slot; 119 return ret; 120 } 121 /* 122 * Note when io_fixed_fd_install() returns error value, it will ensure 123 * fput() is called correspondingly. 124 */ 125 int io_fixed_fd_install(struct io_kiocb *req, unsigned int issue_flags, 126 struct file *file, unsigned int file_slot) 127 { 128 struct io_ring_ctx *ctx = req->ctx; 129 int ret; 130 131 io_ring_submit_lock(ctx, issue_flags); 132 ret = __io_fixed_fd_install(ctx, file, file_slot); 133 io_ring_submit_unlock(ctx, issue_flags); 134 135 if (unlikely(ret < 0)) 136 fput(file); 137 return ret; 138 } 139 140 int io_fixed_fd_remove(struct io_ring_ctx *ctx, unsigned int offset) 141 { 142 struct io_fixed_file *file_slot; 143 struct file *file; 144 int ret; 145 146 if (unlikely(!ctx->file_data)) 147 return -ENXIO; 148 if (offset >= ctx->nr_user_files) 149 return -EINVAL; 150 151 offset = array_index_nospec(offset, ctx->nr_user_files); 152 file_slot = io_fixed_file_slot(&ctx->file_table, offset); 153 if (!file_slot->file_ptr) 154 return -EBADF; 155 156 file = (struct file *)(file_slot->file_ptr & FFS_MASK); 157 ret = io_queue_rsrc_removal(ctx->file_data, offset, file); 158 if (ret) 159 return ret; 160 161 file_slot->file_ptr = 0; 162 io_file_bitmap_clear(&ctx->file_table, offset); 163 return 0; 164 } 165 166 int io_register_file_alloc_range(struct io_ring_ctx *ctx, 167 struct io_uring_file_index_range __user *arg) 168 { 169 struct io_uring_file_index_range range; 170 u32 end; 171 172 if (copy_from_user(&range, arg, sizeof(range))) 173 return -EFAULT; 174 if (check_add_overflow(range.off, range.len, &end)) 175 return -EOVERFLOW; 176 if (range.resv || end > ctx->nr_user_files) 177 return -EINVAL; 178 179 io_file_table_set_alloc_range(ctx, range.off, range.len); 180 return 0; 181 } 182