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 "msg_ring.h" 15 16 /* All valid masks for MSG_RING */ 17 #define IORING_MSG_RING_MASK (IORING_MSG_RING_CQE_SKIP | \ 18 IORING_MSG_RING_FLAGS_PASS) 19 20 struct io_msg { 21 struct file *file; 22 struct file *src_file; 23 struct callback_head tw; 24 u64 user_data; 25 u32 len; 26 u32 cmd; 27 u32 src_fd; 28 union { 29 u32 dst_fd; 30 u32 cqe_flags; 31 }; 32 u32 flags; 33 }; 34 35 static void io_double_unlock_ctx(struct io_ring_ctx *octx) 36 { 37 mutex_unlock(&octx->uring_lock); 38 } 39 40 static int io_lock_external_ctx(struct io_ring_ctx *octx, 41 unsigned int issue_flags) 42 { 43 /* 44 * To ensure proper ordering between the two ctxs, we can only 45 * attempt a trylock on the target. If that fails and we already have 46 * the source ctx lock, punt to io-wq. 47 */ 48 if (!(issue_flags & IO_URING_F_UNLOCKED)) { 49 if (!mutex_trylock(&octx->uring_lock)) 50 return -EAGAIN; 51 return 0; 52 } 53 mutex_lock(&octx->uring_lock); 54 return 0; 55 } 56 57 void io_msg_ring_cleanup(struct io_kiocb *req) 58 { 59 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg); 60 61 if (WARN_ON_ONCE(!msg->src_file)) 62 return; 63 64 fput(msg->src_file); 65 msg->src_file = NULL; 66 } 67 68 static inline bool io_msg_need_remote(struct io_ring_ctx *target_ctx) 69 { 70 return target_ctx->int_flags & IO_RING_F_TASK_COMPLETE; 71 } 72 73 static void io_msg_tw_complete(struct io_tw_req tw_req, io_tw_token_t tw) 74 { 75 struct io_kiocb *req = tw_req.req; 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 kfree_rcu(req, rcu_head); 80 percpu_ref_put(&ctx->refs); 81 } 82 83 static void io_msg_remote_post(struct io_ring_ctx *ctx, struct io_kiocb *req, 84 int res, u32 cflags, u64 user_data) 85 { 86 req->opcode = IORING_OP_NOP; 87 req->cqe.user_data = user_data; 88 io_req_set_res(req, res, cflags); 89 percpu_ref_get(&ctx->refs); 90 req->ctx = ctx; 91 req->tctx = NULL; 92 req->io_task_work.func = io_msg_tw_complete; 93 io_req_task_work_add_remote(req, IOU_F_TWQ_LAZY_WAKE); 94 } 95 96 static int io_msg_ring_cqe_flags(struct io_ring_ctx *target_ctx, 97 const struct io_msg *msg, u32 *flags) 98 { 99 *flags = 0; 100 101 if (!(msg->flags & IORING_MSG_RING_FLAGS_PASS)) 102 return 0; 103 104 *flags = msg->cqe_flags; 105 if ((*flags & IORING_CQE_F_32) && 106 !(target_ctx->flags & (IORING_SETUP_CQE32 | 107 IORING_SETUP_CQE_MIXED))) 108 return -EINVAL; 109 110 return 0; 111 } 112 113 static int io_msg_data_remote(struct io_ring_ctx *target_ctx, 114 struct io_msg *msg) 115 { 116 struct io_kiocb *target; 117 u32 flags; 118 int ret; 119 120 ret = io_msg_ring_cqe_flags(target_ctx, msg, &flags); 121 if (ret) 122 return ret; 123 124 target = kmem_cache_alloc(req_cachep, GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO); 125 if (unlikely(!target)) 126 return -ENOMEM; 127 128 io_msg_remote_post(target_ctx, target, msg->len, flags, msg->user_data); 129 return 0; 130 } 131 132 static int __io_msg_ring_data(struct io_ring_ctx *target_ctx, 133 struct io_msg *msg, unsigned int issue_flags) 134 { 135 u32 flags = 0; 136 int ret; 137 138 if (msg->src_fd || msg->flags & ~IORING_MSG_RING_FLAGS_PASS) 139 return -EINVAL; 140 if (!(msg->flags & IORING_MSG_RING_FLAGS_PASS) && msg->dst_fd) 141 return -EINVAL; 142 /* 143 * Keep IORING_SETUP_R_DISABLED check before submitter_task load 144 * in io_msg_data_remote() -> io_req_task_work_add_remote() 145 */ 146 if (smp_load_acquire(&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 ret = io_msg_ring_cqe_flags(target_ctx, msg, &flags); 153 if (ret) 154 return ret; 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 = ctx->submitter_task; 246 247 init_task_work(&msg->tw, io_msg_tw_fd_complete); 248 if (task_work_add(task, &msg->tw, TWA_SIGNAL)) 249 return -EOWNERDEAD; 250 251 return IOU_ISSUE_SKIP_COMPLETE; 252 } 253 254 static int io_msg_send_fd(struct io_kiocb *req, unsigned int issue_flags) 255 { 256 struct io_ring_ctx *target_ctx = req->file->private_data; 257 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg); 258 struct io_ring_ctx *ctx = req->ctx; 259 260 if (msg->len) 261 return -EINVAL; 262 if (target_ctx == ctx) 263 return -EINVAL; 264 /* 265 * Keep IORING_SETUP_R_DISABLED check before submitter_task load 266 * in io_msg_fd_remote() 267 */ 268 if (smp_load_acquire(&target_ctx->flags) & IORING_SETUP_R_DISABLED) 269 return -EBADFD; 270 if (!msg->src_file) { 271 int ret = io_msg_grab_file(req, issue_flags); 272 if (unlikely(ret)) 273 return ret; 274 } 275 276 if (io_msg_need_remote(target_ctx)) 277 return io_msg_fd_remote(req); 278 return io_msg_install_complete(req, issue_flags); 279 } 280 281 static int __io_msg_ring_prep(struct io_msg *msg, const struct io_uring_sqe *sqe) 282 { 283 if (unlikely(sqe->buf_index || sqe->personality)) 284 return -EINVAL; 285 286 msg->src_file = NULL; 287 msg->user_data = READ_ONCE(sqe->off); 288 msg->len = READ_ONCE(sqe->len); 289 msg->cmd = READ_ONCE(sqe->addr); 290 msg->src_fd = READ_ONCE(sqe->addr3); 291 msg->dst_fd = READ_ONCE(sqe->file_index); 292 msg->flags = READ_ONCE(sqe->msg_ring_flags); 293 if (msg->flags & ~IORING_MSG_RING_MASK) 294 return -EINVAL; 295 296 return 0; 297 } 298 299 int io_msg_ring_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) 300 { 301 return __io_msg_ring_prep(io_kiocb_to_cmd(req, struct io_msg), sqe); 302 } 303 304 int io_msg_ring(struct io_kiocb *req, unsigned int issue_flags) 305 { 306 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg); 307 int ret; 308 309 ret = -EBADFD; 310 if (!io_is_uring_fops(req->file)) 311 goto done; 312 313 switch (msg->cmd) { 314 case IORING_MSG_DATA: 315 ret = io_msg_ring_data(req, issue_flags); 316 break; 317 case IORING_MSG_SEND_FD: 318 ret = io_msg_send_fd(req, issue_flags); 319 break; 320 default: 321 ret = -EINVAL; 322 break; 323 } 324 325 done: 326 if (ret < 0) { 327 if (ret == -EAGAIN || ret == IOU_ISSUE_SKIP_COMPLETE) 328 return ret; 329 req_set_fail(req); 330 } 331 io_req_set_res(req, ret, 0); 332 return IOU_COMPLETE; 333 } 334 335 int io_uring_sync_msg_ring(struct io_uring_sqe *sqe) 336 { 337 struct io_msg io_msg = { }; 338 int ret; 339 340 ret = __io_msg_ring_prep(&io_msg, sqe); 341 if (unlikely(ret)) 342 return ret; 343 344 /* 345 * Only data sending supported, not IORING_MSG_SEND_FD as that one 346 * doesn't make sense without a source ring to send files from. 347 */ 348 if (io_msg.cmd != IORING_MSG_DATA) 349 return -EINVAL; 350 351 CLASS(fd, f)(sqe->fd); 352 if (fd_empty(f)) 353 return -EBADF; 354 if (!io_is_uring_fops(fd_file(f))) 355 return -EBADFD; 356 return __io_msg_ring_data(fd_file(f)->private_data, 357 &io_msg, IO_URING_F_UNLOCKED); 358 } 359