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/slab.h> 6 #include <linux/nospec.h> 7 #include <linux/io_uring.h> 8 9 #include <uapi/linux/io_uring.h> 10 11 #include "io_uring.h" 12 #include "rsrc.h" 13 #include "filetable.h" 14 #include "alloc_cache.h" 15 #include "msg_ring.h" 16 17 /* All valid masks for MSG_RING */ 18 #define IORING_MSG_RING_MASK (IORING_MSG_RING_CQE_SKIP | \ 19 IORING_MSG_RING_FLAGS_PASS) 20 21 struct io_msg { 22 struct file *file; 23 struct file *src_file; 24 struct callback_head tw; 25 u64 user_data; 26 u32 len; 27 u32 cmd; 28 u32 src_fd; 29 union { 30 u32 dst_fd; 31 u32 cqe_flags; 32 }; 33 u32 flags; 34 }; 35 36 static void io_double_unlock_ctx(struct io_ring_ctx *octx) 37 { 38 mutex_unlock(&octx->uring_lock); 39 } 40 41 static int io_double_lock_ctx(struct io_ring_ctx *octx, 42 unsigned int issue_flags) 43 { 44 /* 45 * To ensure proper ordering between the two ctxs, we can only 46 * attempt a trylock on the target. If that fails and we already have 47 * the source ctx lock, punt to io-wq. 48 */ 49 if (!(issue_flags & IO_URING_F_UNLOCKED)) { 50 if (!mutex_trylock(&octx->uring_lock)) 51 return -EAGAIN; 52 return 0; 53 } 54 mutex_lock(&octx->uring_lock); 55 return 0; 56 } 57 58 void io_msg_ring_cleanup(struct io_kiocb *req) 59 { 60 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg); 61 62 if (WARN_ON_ONCE(!msg->src_file)) 63 return; 64 65 fput(msg->src_file); 66 msg->src_file = NULL; 67 } 68 69 static inline bool io_msg_need_remote(struct io_ring_ctx *target_ctx) 70 { 71 return target_ctx->task_complete; 72 } 73 74 static void io_msg_tw_complete(struct io_kiocb *req, struct io_tw_state *ts) 75 { 76 struct io_ring_ctx *ctx = req->ctx; 77 78 io_add_aux_cqe(ctx, req->cqe.user_data, req->cqe.res, req->cqe.flags); 79 if (spin_trylock(&ctx->msg_lock)) { 80 if (io_alloc_cache_put(&ctx->msg_cache, req)) 81 req = NULL; 82 spin_unlock(&ctx->msg_lock); 83 } 84 if (req) 85 kmem_cache_free(req_cachep, req); 86 percpu_ref_put(&ctx->refs); 87 } 88 89 static int io_msg_remote_post(struct io_ring_ctx *ctx, struct io_kiocb *req, 90 int res, u32 cflags, u64 user_data) 91 { 92 req->tctx = READ_ONCE(ctx->submitter_task->io_uring); 93 if (!req->tctx) { 94 kmem_cache_free(req_cachep, req); 95 return -EOWNERDEAD; 96 } 97 req->cqe.user_data = user_data; 98 io_req_set_res(req, res, cflags); 99 percpu_ref_get(&ctx->refs); 100 req->ctx = ctx; 101 req->io_task_work.func = io_msg_tw_complete; 102 io_req_task_work_add_remote(req, ctx, IOU_F_TWQ_LAZY_WAKE); 103 return 0; 104 } 105 106 static struct io_kiocb *io_msg_get_kiocb(struct io_ring_ctx *ctx) 107 { 108 struct io_kiocb *req = NULL; 109 110 if (spin_trylock(&ctx->msg_lock)) { 111 req = io_alloc_cache_get(&ctx->msg_cache); 112 spin_unlock(&ctx->msg_lock); 113 if (req) 114 return req; 115 } 116 return kmem_cache_alloc(req_cachep, GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO); 117 } 118 119 static int io_msg_data_remote(struct io_ring_ctx *target_ctx, 120 struct io_msg *msg) 121 { 122 struct io_kiocb *target; 123 u32 flags = 0; 124 125 target = io_msg_get_kiocb(target_ctx); 126 if (unlikely(!target)) 127 return -ENOMEM; 128 129 if (msg->flags & IORING_MSG_RING_FLAGS_PASS) 130 flags = msg->cqe_flags; 131 132 return io_msg_remote_post(target_ctx, target, msg->len, flags, 133 msg->user_data); 134 } 135 136 static int __io_msg_ring_data(struct io_ring_ctx *target_ctx, 137 struct io_msg *msg, unsigned int issue_flags) 138 { 139 u32 flags = 0; 140 int ret; 141 142 if (msg->src_fd || msg->flags & ~IORING_MSG_RING_FLAGS_PASS) 143 return -EINVAL; 144 if (!(msg->flags & IORING_MSG_RING_FLAGS_PASS) && msg->dst_fd) 145 return -EINVAL; 146 if (target_ctx->flags & IORING_SETUP_R_DISABLED) 147 return -EBADFD; 148 149 if (io_msg_need_remote(target_ctx)) 150 return io_msg_data_remote(target_ctx, msg); 151 152 if (msg->flags & IORING_MSG_RING_FLAGS_PASS) 153 flags = msg->cqe_flags; 154 155 ret = -EOVERFLOW; 156 if (target_ctx->flags & IORING_SETUP_IOPOLL) { 157 if (unlikely(io_double_lock_ctx(target_ctx, issue_flags))) 158 return -EAGAIN; 159 } 160 if (io_post_aux_cqe(target_ctx, msg->user_data, msg->len, flags)) 161 ret = 0; 162 if (target_ctx->flags & IORING_SETUP_IOPOLL) 163 io_double_unlock_ctx(target_ctx); 164 return ret; 165 } 166 167 static int io_msg_ring_data(struct io_kiocb *req, unsigned int issue_flags) 168 { 169 struct io_ring_ctx *target_ctx = req->file->private_data; 170 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg); 171 172 return __io_msg_ring_data(target_ctx, msg, issue_flags); 173 } 174 175 static int io_msg_grab_file(struct io_kiocb *req, unsigned int issue_flags) 176 { 177 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg); 178 struct io_ring_ctx *ctx = req->ctx; 179 struct io_rsrc_node *node; 180 int ret = -EBADF; 181 182 io_ring_submit_lock(ctx, issue_flags); 183 node = io_rsrc_node_lookup(&ctx->file_table.data, msg->src_fd); 184 if (node) { 185 msg->src_file = io_slot_file(node); 186 if (msg->src_file) 187 get_file(msg->src_file); 188 req->flags |= REQ_F_NEED_CLEANUP; 189 ret = 0; 190 } 191 io_ring_submit_unlock(ctx, issue_flags); 192 return ret; 193 } 194 195 static int io_msg_install_complete(struct io_kiocb *req, unsigned int issue_flags) 196 { 197 struct io_ring_ctx *target_ctx = req->file->private_data; 198 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg); 199 struct file *src_file = msg->src_file; 200 int ret; 201 202 if (unlikely(io_double_lock_ctx(target_ctx, issue_flags))) 203 return -EAGAIN; 204 205 ret = __io_fixed_fd_install(target_ctx, src_file, msg->dst_fd); 206 if (ret < 0) 207 goto out_unlock; 208 209 msg->src_file = NULL; 210 req->flags &= ~REQ_F_NEED_CLEANUP; 211 212 if (msg->flags & IORING_MSG_RING_CQE_SKIP) 213 goto out_unlock; 214 /* 215 * If this fails, the target still received the file descriptor but 216 * wasn't notified of the fact. This means that if this request 217 * completes with -EOVERFLOW, then the sender must ensure that a 218 * later IORING_OP_MSG_RING delivers the message. 219 */ 220 if (!io_post_aux_cqe(target_ctx, msg->user_data, ret, 0)) 221 ret = -EOVERFLOW; 222 out_unlock: 223 io_double_unlock_ctx(target_ctx); 224 return ret; 225 } 226 227 static void io_msg_tw_fd_complete(struct callback_head *head) 228 { 229 struct io_msg *msg = container_of(head, struct io_msg, tw); 230 struct io_kiocb *req = cmd_to_io_kiocb(msg); 231 int ret = -EOWNERDEAD; 232 233 if (!(current->flags & PF_EXITING)) 234 ret = io_msg_install_complete(req, IO_URING_F_UNLOCKED); 235 if (ret < 0) 236 req_set_fail(req); 237 io_req_queue_tw_complete(req, ret); 238 } 239 240 static int io_msg_fd_remote(struct io_kiocb *req) 241 { 242 struct io_ring_ctx *ctx = req->file->private_data; 243 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg); 244 struct task_struct *task = READ_ONCE(ctx->submitter_task); 245 246 if (unlikely(!task)) 247 return -EOWNERDEAD; 248 249 init_task_work(&msg->tw, io_msg_tw_fd_complete); 250 if (task_work_add(task, &msg->tw, TWA_SIGNAL)) 251 return -EOWNERDEAD; 252 253 return IOU_ISSUE_SKIP_COMPLETE; 254 } 255 256 static int io_msg_send_fd(struct io_kiocb *req, unsigned int issue_flags) 257 { 258 struct io_ring_ctx *target_ctx = req->file->private_data; 259 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg); 260 struct io_ring_ctx *ctx = req->ctx; 261 262 if (msg->len) 263 return -EINVAL; 264 if (target_ctx == ctx) 265 return -EINVAL; 266 if (target_ctx->flags & IORING_SETUP_R_DISABLED) 267 return -EBADFD; 268 if (!msg->src_file) { 269 int ret = io_msg_grab_file(req, issue_flags); 270 if (unlikely(ret)) 271 return ret; 272 } 273 274 if (io_msg_need_remote(target_ctx)) 275 return io_msg_fd_remote(req); 276 return io_msg_install_complete(req, issue_flags); 277 } 278 279 static int __io_msg_ring_prep(struct io_msg *msg, const struct io_uring_sqe *sqe) 280 { 281 if (unlikely(sqe->buf_index || sqe->personality)) 282 return -EINVAL; 283 284 msg->src_file = NULL; 285 msg->user_data = READ_ONCE(sqe->off); 286 msg->len = READ_ONCE(sqe->len); 287 msg->cmd = READ_ONCE(sqe->addr); 288 msg->src_fd = READ_ONCE(sqe->addr3); 289 msg->dst_fd = READ_ONCE(sqe->file_index); 290 msg->flags = READ_ONCE(sqe->msg_ring_flags); 291 if (msg->flags & ~IORING_MSG_RING_MASK) 292 return -EINVAL; 293 294 return 0; 295 } 296 297 int io_msg_ring_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) 298 { 299 return __io_msg_ring_prep(io_kiocb_to_cmd(req, struct io_msg), sqe); 300 } 301 302 int io_msg_ring(struct io_kiocb *req, unsigned int issue_flags) 303 { 304 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg); 305 int ret; 306 307 ret = -EBADFD; 308 if (!io_is_uring_fops(req->file)) 309 goto done; 310 311 switch (msg->cmd) { 312 case IORING_MSG_DATA: 313 ret = io_msg_ring_data(req, issue_flags); 314 break; 315 case IORING_MSG_SEND_FD: 316 ret = io_msg_send_fd(req, issue_flags); 317 break; 318 default: 319 ret = -EINVAL; 320 break; 321 } 322 323 done: 324 if (ret < 0) { 325 if (ret == -EAGAIN || ret == IOU_ISSUE_SKIP_COMPLETE) 326 return ret; 327 req_set_fail(req); 328 } 329 io_req_set_res(req, ret, 0); 330 return IOU_OK; 331 } 332 333 int io_uring_sync_msg_ring(struct io_uring_sqe *sqe) 334 { 335 struct io_msg io_msg = { }; 336 int ret; 337 338 ret = __io_msg_ring_prep(&io_msg, sqe); 339 if (unlikely(ret)) 340 return ret; 341 342 /* 343 * Only data sending supported, not IORING_MSG_SEND_FD as that one 344 * doesn't make sense without a source ring to send files from. 345 */ 346 if (io_msg.cmd != IORING_MSG_DATA) 347 return -EINVAL; 348 349 CLASS(fd, f)(sqe->fd); 350 if (fd_empty(f)) 351 return -EBADF; 352 if (!io_is_uring_fops(fd_file(f))) 353 return -EBADFD; 354 return __io_msg_ring_data(fd_file(f)->private_data, 355 &io_msg, IO_URING_F_UNLOCKED); 356 } 357 358 void io_msg_cache_free(const void *entry) 359 { 360 struct io_kiocb *req = (struct io_kiocb *) entry; 361 362 kmem_cache_free(req_cachep, req); 363 } 364