1 // SPDX-License-Identifier: GPL-2.0 2 3 #include "linux/io_uring/query.h" 4 5 #include "query.h" 6 #include "io_uring.h" 7 8 #define IO_MAX_QUERY_SIZE (sizeof(struct io_uring_query_opcode)) 9 #define IO_MAX_QUERY_ENTRIES 1000 10 11 static ssize_t io_query_ops(void *data) 12 { 13 struct io_uring_query_opcode *e = data; 14 15 BUILD_BUG_ON(sizeof(*e) > IO_MAX_QUERY_SIZE); 16 17 e->nr_request_opcodes = IORING_OP_LAST; 18 e->nr_register_opcodes = IORING_REGISTER_LAST; 19 e->feature_flags = IORING_FEAT_FLAGS; 20 e->ring_setup_flags = IORING_SETUP_FLAGS; 21 e->enter_flags = IORING_ENTER_FLAGS; 22 e->sqe_flags = SQE_VALID_FLAGS; 23 return sizeof(*e); 24 } 25 26 static int io_handle_query_entry(struct io_ring_ctx *ctx, 27 void *data, void __user *uhdr, 28 u64 *next_entry) 29 { 30 struct io_uring_query_hdr hdr; 31 size_t usize, res_size = 0; 32 ssize_t ret = -EINVAL; 33 void __user *udata; 34 35 if (copy_from_user(&hdr, uhdr, sizeof(hdr))) 36 return -EFAULT; 37 usize = hdr.size; 38 hdr.size = min(hdr.size, IO_MAX_QUERY_SIZE); 39 udata = u64_to_user_ptr(hdr.query_data); 40 41 if (hdr.query_op >= __IO_URING_QUERY_MAX) { 42 ret = -EOPNOTSUPP; 43 goto out; 44 } 45 if (!mem_is_zero(hdr.__resv, sizeof(hdr.__resv)) || hdr.result || !hdr.size) 46 goto out; 47 if (copy_from_user(data, udata, hdr.size)) 48 return -EFAULT; 49 50 switch (hdr.query_op) { 51 case IO_URING_QUERY_OPCODES: 52 ret = io_query_ops(data); 53 break; 54 } 55 56 if (ret >= 0) { 57 if (WARN_ON_ONCE(ret > IO_MAX_QUERY_SIZE)) 58 return -EFAULT; 59 res_size = ret; 60 ret = 0; 61 } 62 out: 63 hdr.result = ret; 64 hdr.size = min_t(size_t, usize, res_size); 65 66 if (copy_struct_to_user(udata, usize, data, hdr.size, NULL)) 67 return -EFAULT; 68 if (copy_to_user(uhdr, &hdr, sizeof(hdr))) 69 return -EFAULT; 70 *next_entry = hdr.next_entry; 71 return 0; 72 } 73 74 int io_query(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args) 75 { 76 char entry_buffer[IO_MAX_QUERY_SIZE]; 77 void __user *uhdr = arg; 78 int ret, nr = 0; 79 80 memset(entry_buffer, 0, sizeof(entry_buffer)); 81 82 if (nr_args) 83 return -EINVAL; 84 85 while (uhdr) { 86 u64 next_hdr; 87 88 ret = io_handle_query_entry(ctx, entry_buffer, uhdr, &next_hdr); 89 if (ret) 90 return ret; 91 uhdr = u64_to_user_ptr(next_hdr); 92 93 /* Have some limit to avoid a potential cycle */ 94 if (++nr >= IO_MAX_QUERY_ENTRIES) 95 return -ERANGE; 96 if (fatal_signal_pending(current)) 97 return -EINTR; 98 cond_resched(); 99 } 100 return 0; 101 } 102