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