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_lock_external_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, io_tw_token_t tw) 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 if (!READ_ONCE(ctx->submitter_task)) { 93 kmem_cache_free(req_cachep, req); 94 return -EOWNERDEAD; 95 } 96 req->opcode = IORING_OP_NOP; 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->tctx = NULL; 102 req->io_task_work.func = io_msg_tw_complete; 103 io_req_task_work_add_remote(req, IOU_F_TWQ_LAZY_WAKE); 104 return 0; 105 } 106 107 static struct io_kiocb *io_msg_get_kiocb(struct io_ring_ctx *ctx) 108 { 109 struct io_kiocb *req = NULL; 110 111 if (spin_trylock(&ctx->msg_lock)) { 112 req = io_alloc_cache_get(&ctx->msg_cache); 113 spin_unlock(&ctx->msg_lock); 114 if (req) 115 return req; 116 } 117 return kmem_cache_alloc(req_cachep, GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO); 118 } 119 120 static int io_msg_data_remote(struct io_ring_ctx *target_ctx, 121 struct io_msg *msg) 122 { 123 struct io_kiocb *target; 124 u32 flags = 0; 125 126 target = io_msg_get_kiocb(target_ctx); 127 if (unlikely(!target)) 128 return -ENOMEM; 129 130 if (msg->flags & IORING_MSG_RING_FLAGS_PASS) 131 flags = msg->cqe_flags; 132 133 return io_msg_remote_post(target_ctx, target, msg->len, flags, 134 msg->user_data); 135 } 136 137 static int __io_msg_ring_data(struct io_ring_ctx *target_ctx, 138 struct io_msg *msg, unsigned int issue_flags) 139 { 140 u32 flags = 0; 141 int ret; 142 143 if (msg->src_fd || msg->flags & ~IORING_MSG_RING_FLAGS_PASS) 144 return -EINVAL; 145 if (!(msg->flags & IORING_MSG_RING_FLAGS_PASS) && msg->dst_fd) 146 return -EINVAL; 147 if (target_ctx->flags & IORING_SETUP_R_DISABLED) 148 return -EBADFD; 149 150 if (io_msg_need_remote(target_ctx)) 151 return io_msg_data_remote(target_ctx, msg); 152 153 if (msg->flags & IORING_MSG_RING_FLAGS_PASS) 154 flags = msg->cqe_flags; 155 156 ret = -EOVERFLOW; 157 if (target_ctx->flags & IORING_SETUP_IOPOLL) { 158 if (unlikely(io_lock_external_ctx(target_ctx, issue_flags))) 159 return -EAGAIN; 160 } 161 if (io_post_aux_cqe(target_ctx, msg->user_data, msg->len, flags)) 162 ret = 0; 163 if (target_ctx->flags & IORING_SETUP_IOPOLL) 164 io_double_unlock_ctx(target_ctx); 165 return ret; 166 } 167 168 static int io_msg_ring_data(struct io_kiocb *req, unsigned int issue_flags) 169 { 170 struct io_ring_ctx *target_ctx = req->file->private_data; 171 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg); 172 173 return __io_msg_ring_data(target_ctx, msg, issue_flags); 174 } 175 176 static int io_msg_grab_file(struct io_kiocb *req, unsigned int issue_flags) 177 { 178 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg); 179 struct io_ring_ctx *ctx = req->ctx; 180 struct io_rsrc_node *node; 181 int ret = -EBADF; 182 183 io_ring_submit_lock(ctx, issue_flags); 184 node = io_rsrc_node_lookup(&ctx->file_table.data, msg->src_fd); 185 if (node) { 186 msg->src_file = io_slot_file(node); 187 if (msg->src_file) 188 get_file(msg->src_file); 189 req->flags |= REQ_F_NEED_CLEANUP; 190 ret = 0; 191 } 192 io_ring_submit_unlock(ctx, issue_flags); 193 return ret; 194 } 195 196 static int io_msg_install_complete(struct io_kiocb *req, unsigned int issue_flags) 197 { 198 struct io_ring_ctx *target_ctx = req->file->private_data; 199 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg); 200 struct file *src_file = msg->src_file; 201 int ret; 202 203 if (unlikely(io_lock_external_ctx(target_ctx, issue_flags))) 204 return -EAGAIN; 205 206 ret = __io_fixed_fd_install(target_ctx, src_file, msg->dst_fd); 207 if (ret < 0) 208 goto out_unlock; 209 210 msg->src_file = NULL; 211 req->flags &= ~REQ_F_NEED_CLEANUP; 212 213 if (msg->flags & IORING_MSG_RING_CQE_SKIP) 214 goto out_unlock; 215 /* 216 * If this fails, the target still received the file descriptor but 217 * wasn't notified of the fact. This means that if this request 218 * completes with -EOVERFLOW, then the sender must ensure that a 219 * later IORING_OP_MSG_RING delivers the message. 220 */ 221 if (!io_post_aux_cqe(target_ctx, msg->user_data, ret, 0)) 222 ret = -EOVERFLOW; 223 out_unlock: 224 io_double_unlock_ctx(target_ctx); 225 return ret; 226 } 227 228 static void io_msg_tw_fd_complete(struct callback_head *head) 229 { 230 struct io_msg *msg = container_of(head, struct io_msg, tw); 231 struct io_kiocb *req = cmd_to_io_kiocb(msg); 232 int ret = -EOWNERDEAD; 233 234 if (!(current->flags & PF_EXITING)) 235 ret = io_msg_install_complete(req, IO_URING_F_UNLOCKED); 236 if (ret < 0) 237 req_set_fail(req); 238 io_req_queue_tw_complete(req, ret); 239 } 240 241 static int io_msg_fd_remote(struct io_kiocb *req) 242 { 243 struct io_ring_ctx *ctx = req->file->private_data; 244 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg); 245 struct task_struct *task = READ_ONCE(ctx->submitter_task); 246 247 if (unlikely(!task)) 248 return -EOWNERDEAD; 249 250 init_task_work(&msg->tw, io_msg_tw_fd_complete); 251 if (task_work_add(task, &msg->tw, TWA_SIGNAL)) 252 return -EOWNERDEAD; 253 254 return IOU_ISSUE_SKIP_COMPLETE; 255 } 256 257 static int io_msg_send_fd(struct io_kiocb *req, unsigned int issue_flags) 258 { 259 struct io_ring_ctx *target_ctx = req->file->private_data; 260 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg); 261 struct io_ring_ctx *ctx = req->ctx; 262 263 if (msg->len) 264 return -EINVAL; 265 if (target_ctx == ctx) 266 return -EINVAL; 267 if (target_ctx->flags & IORING_SETUP_R_DISABLED) 268 return -EBADFD; 269 if (!msg->src_file) { 270 int ret = io_msg_grab_file(req, issue_flags); 271 if (unlikely(ret)) 272 return ret; 273 } 274 275 if (io_msg_need_remote(target_ctx)) 276 return io_msg_fd_remote(req); 277 return io_msg_install_complete(req, issue_flags); 278 } 279 280 static int __io_msg_ring_prep(struct io_msg *msg, const struct io_uring_sqe *sqe) 281 { 282 if (unlikely(sqe->buf_index || sqe->personality)) 283 return -EINVAL; 284 285 msg->src_file = NULL; 286 msg->user_data = READ_ONCE(sqe->off); 287 msg->len = READ_ONCE(sqe->len); 288 msg->cmd = READ_ONCE(sqe->addr); 289 msg->src_fd = READ_ONCE(sqe->addr3); 290 msg->dst_fd = READ_ONCE(sqe->file_index); 291 msg->flags = READ_ONCE(sqe->msg_ring_flags); 292 if (msg->flags & ~IORING_MSG_RING_MASK) 293 return -EINVAL; 294 295 return 0; 296 } 297 298 int io_msg_ring_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) 299 { 300 return __io_msg_ring_prep(io_kiocb_to_cmd(req, struct io_msg), sqe); 301 } 302 303 int io_msg_ring(struct io_kiocb *req, unsigned int issue_flags) 304 { 305 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg); 306 int ret; 307 308 ret = -EBADFD; 309 if (!io_is_uring_fops(req->file)) 310 goto done; 311 312 switch (msg->cmd) { 313 case IORING_MSG_DATA: 314 ret = io_msg_ring_data(req, issue_flags); 315 break; 316 case IORING_MSG_SEND_FD: 317 ret = io_msg_send_fd(req, issue_flags); 318 break; 319 default: 320 ret = -EINVAL; 321 break; 322 } 323 324 done: 325 if (ret < 0) { 326 if (ret == -EAGAIN || ret == IOU_ISSUE_SKIP_COMPLETE) 327 return ret; 328 req_set_fail(req); 329 } 330 io_req_set_res(req, ret, 0); 331 return IOU_OK; 332 } 333 334 int io_uring_sync_msg_ring(struct io_uring_sqe *sqe) 335 { 336 struct io_msg io_msg = { }; 337 int ret; 338 339 ret = __io_msg_ring_prep(&io_msg, sqe); 340 if (unlikely(ret)) 341 return ret; 342 343 /* 344 * Only data sending supported, not IORING_MSG_SEND_FD as that one 345 * doesn't make sense without a source ring to send files from. 346 */ 347 if (io_msg.cmd != IORING_MSG_DATA) 348 return -EINVAL; 349 350 CLASS(fd, f)(sqe->fd); 351 if (fd_empty(f)) 352 return -EBADF; 353 if (!io_is_uring_fops(fd_file(f))) 354 return -EBADFD; 355 return __io_msg_ring_data(fd_file(f)->private_data, 356 &io_msg, IO_URING_F_UNLOCKED); 357 } 358