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