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