1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/kernel.h> 3 #include <linux/errno.h> 4 #include <linux/fs.h> 5 #include <linux/file.h> 6 #include <linux/mm.h> 7 #include <linux/slab.h> 8 #include <linux/namei.h> 9 #include <linux/nospec.h> 10 #include <linux/io_uring.h> 11 12 #include <uapi/linux/io_uring.h> 13 14 #include "io_uring.h" 15 #include "tctx.h" 16 #include "poll.h" 17 #include "timeout.h" 18 #include "waitid.h" 19 #include "futex.h" 20 #include "cancel.h" 21 22 struct io_cancel { 23 struct file *file; 24 u64 addr; 25 u32 flags; 26 s32 fd; 27 u8 opcode; 28 }; 29 30 #define CANCEL_FLAGS (IORING_ASYNC_CANCEL_ALL | IORING_ASYNC_CANCEL_FD | \ 31 IORING_ASYNC_CANCEL_ANY | IORING_ASYNC_CANCEL_FD_FIXED | \ 32 IORING_ASYNC_CANCEL_USERDATA | IORING_ASYNC_CANCEL_OP) 33 34 /* 35 * Returns true if the request matches the criteria outlined by 'cd'. 36 */ 37 bool io_cancel_req_match(struct io_kiocb *req, struct io_cancel_data *cd) 38 { 39 bool match_user_data = cd->flags & IORING_ASYNC_CANCEL_USERDATA; 40 41 if (req->ctx != cd->ctx) 42 return false; 43 44 if (!(cd->flags & (IORING_ASYNC_CANCEL_FD | IORING_ASYNC_CANCEL_OP))) 45 match_user_data = true; 46 47 if (cd->flags & IORING_ASYNC_CANCEL_ANY) 48 goto check_seq; 49 if (cd->flags & IORING_ASYNC_CANCEL_FD) { 50 if (req->file != cd->file) 51 return false; 52 } 53 if (cd->flags & IORING_ASYNC_CANCEL_OP) { 54 if (req->opcode != cd->opcode) 55 return false; 56 } 57 if (match_user_data && req->cqe.user_data != cd->data) 58 return false; 59 if (cd->flags & IORING_ASYNC_CANCEL_ALL) { 60 check_seq: 61 if (cd->seq == req->work.cancel_seq) 62 return false; 63 req->work.cancel_seq = cd->seq; 64 } 65 66 return true; 67 } 68 69 static bool io_cancel_cb(struct io_wq_work *work, void *data) 70 { 71 struct io_kiocb *req = container_of(work, struct io_kiocb, work); 72 struct io_cancel_data *cd = data; 73 74 return io_cancel_req_match(req, cd); 75 } 76 77 static int io_async_cancel_one(struct io_uring_task *tctx, 78 struct io_cancel_data *cd) 79 { 80 enum io_wq_cancel cancel_ret; 81 int ret = 0; 82 bool all; 83 84 if (!tctx || !tctx->io_wq) 85 return -ENOENT; 86 87 all = cd->flags & (IORING_ASYNC_CANCEL_ALL|IORING_ASYNC_CANCEL_ANY); 88 cancel_ret = io_wq_cancel_cb(tctx->io_wq, io_cancel_cb, cd, all); 89 switch (cancel_ret) { 90 case IO_WQ_CANCEL_OK: 91 ret = 0; 92 break; 93 case IO_WQ_CANCEL_RUNNING: 94 ret = -EALREADY; 95 break; 96 case IO_WQ_CANCEL_NOTFOUND: 97 ret = -ENOENT; 98 break; 99 } 100 101 return ret; 102 } 103 104 int io_try_cancel(struct io_uring_task *tctx, struct io_cancel_data *cd, 105 unsigned issue_flags) 106 { 107 struct io_ring_ctx *ctx = cd->ctx; 108 int ret; 109 110 WARN_ON_ONCE(!io_wq_current_is_worker() && tctx != current->io_uring); 111 112 ret = io_async_cancel_one(tctx, cd); 113 /* 114 * Fall-through even for -EALREADY, as we may have poll armed 115 * that need unarming. 116 */ 117 if (!ret) 118 return 0; 119 120 ret = io_poll_cancel(ctx, cd, issue_flags); 121 if (ret != -ENOENT) 122 return ret; 123 124 ret = io_waitid_cancel(ctx, cd, issue_flags); 125 if (ret != -ENOENT) 126 return ret; 127 128 ret = io_futex_cancel(ctx, cd, issue_flags); 129 if (ret != -ENOENT) 130 return ret; 131 132 spin_lock(&ctx->completion_lock); 133 if (!(cd->flags & IORING_ASYNC_CANCEL_FD)) 134 ret = io_timeout_cancel(ctx, cd); 135 spin_unlock(&ctx->completion_lock); 136 return ret; 137 } 138 139 int io_async_cancel_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) 140 { 141 struct io_cancel *cancel = io_kiocb_to_cmd(req, struct io_cancel); 142 143 if (unlikely(req->flags & REQ_F_BUFFER_SELECT)) 144 return -EINVAL; 145 if (sqe->off || sqe->splice_fd_in) 146 return -EINVAL; 147 148 cancel->addr = READ_ONCE(sqe->addr); 149 cancel->flags = READ_ONCE(sqe->cancel_flags); 150 if (cancel->flags & ~CANCEL_FLAGS) 151 return -EINVAL; 152 if (cancel->flags & IORING_ASYNC_CANCEL_FD) { 153 if (cancel->flags & IORING_ASYNC_CANCEL_ANY) 154 return -EINVAL; 155 cancel->fd = READ_ONCE(sqe->fd); 156 } 157 if (cancel->flags & IORING_ASYNC_CANCEL_OP) { 158 if (cancel->flags & IORING_ASYNC_CANCEL_ANY) 159 return -EINVAL; 160 cancel->opcode = READ_ONCE(sqe->len); 161 } 162 163 return 0; 164 } 165 166 static int __io_async_cancel(struct io_cancel_data *cd, 167 struct io_uring_task *tctx, 168 unsigned int issue_flags) 169 { 170 bool all = cd->flags & (IORING_ASYNC_CANCEL_ALL|IORING_ASYNC_CANCEL_ANY); 171 struct io_ring_ctx *ctx = cd->ctx; 172 struct io_tctx_node *node; 173 int ret, nr = 0; 174 175 do { 176 ret = io_try_cancel(tctx, cd, issue_flags); 177 if (ret == -ENOENT) 178 break; 179 if (!all) 180 return ret; 181 nr++; 182 } while (1); 183 184 /* slow path, try all io-wq's */ 185 io_ring_submit_lock(ctx, issue_flags); 186 ret = -ENOENT; 187 list_for_each_entry(node, &ctx->tctx_list, ctx_node) { 188 struct io_uring_task *tctx = node->task->io_uring; 189 190 ret = io_async_cancel_one(tctx, cd); 191 if (ret != -ENOENT) { 192 if (!all) 193 break; 194 nr++; 195 } 196 } 197 io_ring_submit_unlock(ctx, issue_flags); 198 return all ? nr : ret; 199 } 200 201 int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags) 202 { 203 struct io_cancel *cancel = io_kiocb_to_cmd(req, struct io_cancel); 204 struct io_cancel_data cd = { 205 .ctx = req->ctx, 206 .data = cancel->addr, 207 .flags = cancel->flags, 208 .opcode = cancel->opcode, 209 .seq = atomic_inc_return(&req->ctx->cancel_seq), 210 }; 211 struct io_uring_task *tctx = req->task->io_uring; 212 int ret; 213 214 if (cd.flags & IORING_ASYNC_CANCEL_FD) { 215 if (req->flags & REQ_F_FIXED_FILE || 216 cd.flags & IORING_ASYNC_CANCEL_FD_FIXED) { 217 req->flags |= REQ_F_FIXED_FILE; 218 req->file = io_file_get_fixed(req, cancel->fd, 219 issue_flags); 220 } else { 221 req->file = io_file_get_normal(req, cancel->fd); 222 } 223 if (!req->file) { 224 ret = -EBADF; 225 goto done; 226 } 227 cd.file = req->file; 228 } 229 230 ret = __io_async_cancel(&cd, tctx, issue_flags); 231 done: 232 if (ret < 0) 233 req_set_fail(req); 234 io_req_set_res(req, ret, 0); 235 return IOU_OK; 236 } 237 238 void init_hash_table(struct io_hash_table *table, unsigned size) 239 { 240 unsigned int i; 241 242 for (i = 0; i < size; i++) { 243 spin_lock_init(&table->hbs[i].lock); 244 INIT_HLIST_HEAD(&table->hbs[i].list); 245 } 246 } 247 248 static int __io_sync_cancel(struct io_uring_task *tctx, 249 struct io_cancel_data *cd, int fd) 250 { 251 struct io_ring_ctx *ctx = cd->ctx; 252 253 /* fixed must be grabbed every time since we drop the uring_lock */ 254 if ((cd->flags & IORING_ASYNC_CANCEL_FD) && 255 (cd->flags & IORING_ASYNC_CANCEL_FD_FIXED)) { 256 if (unlikely(fd >= ctx->nr_user_files)) 257 return -EBADF; 258 fd = array_index_nospec(fd, ctx->nr_user_files); 259 cd->file = io_file_from_index(&ctx->file_table, fd); 260 if (!cd->file) 261 return -EBADF; 262 } 263 264 return __io_async_cancel(cd, tctx, 0); 265 } 266 267 int io_sync_cancel(struct io_ring_ctx *ctx, void __user *arg) 268 __must_hold(&ctx->uring_lock) 269 { 270 struct io_cancel_data cd = { 271 .ctx = ctx, 272 .seq = atomic_inc_return(&ctx->cancel_seq), 273 }; 274 ktime_t timeout = KTIME_MAX; 275 struct io_uring_sync_cancel_reg sc; 276 struct file *file = NULL; 277 DEFINE_WAIT(wait); 278 int ret, i; 279 280 if (copy_from_user(&sc, arg, sizeof(sc))) 281 return -EFAULT; 282 if (sc.flags & ~CANCEL_FLAGS) 283 return -EINVAL; 284 for (i = 0; i < ARRAY_SIZE(sc.pad); i++) 285 if (sc.pad[i]) 286 return -EINVAL; 287 for (i = 0; i < ARRAY_SIZE(sc.pad2); i++) 288 if (sc.pad2[i]) 289 return -EINVAL; 290 291 cd.data = sc.addr; 292 cd.flags = sc.flags; 293 cd.opcode = sc.opcode; 294 295 /* we can grab a normal file descriptor upfront */ 296 if ((cd.flags & IORING_ASYNC_CANCEL_FD) && 297 !(cd.flags & IORING_ASYNC_CANCEL_FD_FIXED)) { 298 file = fget(sc.fd); 299 if (!file) 300 return -EBADF; 301 cd.file = file; 302 } 303 304 ret = __io_sync_cancel(current->io_uring, &cd, sc.fd); 305 306 /* found something, done! */ 307 if (ret != -EALREADY) 308 goto out; 309 310 if (sc.timeout.tv_sec != -1UL || sc.timeout.tv_nsec != -1UL) { 311 struct timespec64 ts = { 312 .tv_sec = sc.timeout.tv_sec, 313 .tv_nsec = sc.timeout.tv_nsec 314 }; 315 316 timeout = ktime_add_ns(timespec64_to_ktime(ts), ktime_get_ns()); 317 } 318 319 /* 320 * Keep looking until we get -ENOENT. we'll get woken everytime 321 * every time a request completes and will retry the cancelation. 322 */ 323 do { 324 cd.seq = atomic_inc_return(&ctx->cancel_seq); 325 326 prepare_to_wait(&ctx->cq_wait, &wait, TASK_INTERRUPTIBLE); 327 328 ret = __io_sync_cancel(current->io_uring, &cd, sc.fd); 329 330 mutex_unlock(&ctx->uring_lock); 331 if (ret != -EALREADY) 332 break; 333 334 ret = io_run_task_work_sig(ctx); 335 if (ret < 0) 336 break; 337 ret = schedule_hrtimeout(&timeout, HRTIMER_MODE_ABS); 338 if (!ret) { 339 ret = -ETIME; 340 break; 341 } 342 mutex_lock(&ctx->uring_lock); 343 } while (1); 344 345 finish_wait(&ctx->cq_wait, &wait); 346 mutex_lock(&ctx->uring_lock); 347 348 if (ret == -ENOENT || ret > 0) 349 ret = 0; 350 out: 351 if (file) 352 fput(file); 353 return ret; 354 } 355