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 e->nr_query_opcodes = __IO_URING_QUERY_MAX; 24 e->__pad = 0; 25 return sizeof(*e); 26 } 27 28 static int io_handle_query_entry(struct io_ring_ctx *ctx, 29 void *data, void __user *uhdr, 30 u64 *next_entry) 31 { 32 struct io_uring_query_hdr hdr; 33 size_t usize, res_size = 0; 34 ssize_t ret = -EINVAL; 35 void __user *udata; 36 37 if (copy_from_user(&hdr, uhdr, sizeof(hdr))) 38 return -EFAULT; 39 usize = hdr.size; 40 hdr.size = min(hdr.size, IO_MAX_QUERY_SIZE); 41 udata = u64_to_user_ptr(hdr.query_data); 42 43 if (hdr.query_op >= __IO_URING_QUERY_MAX) { 44 ret = -EOPNOTSUPP; 45 goto out; 46 } 47 if (!mem_is_zero(hdr.__resv, sizeof(hdr.__resv)) || hdr.result || !hdr.size) 48 goto out; 49 if (copy_from_user(data, udata, hdr.size)) 50 return -EFAULT; 51 52 switch (hdr.query_op) { 53 case IO_URING_QUERY_OPCODES: 54 ret = io_query_ops(data); 55 break; 56 } 57 58 if (ret >= 0) { 59 if (WARN_ON_ONCE(ret > IO_MAX_QUERY_SIZE)) 60 return -EFAULT; 61 res_size = ret; 62 ret = 0; 63 } 64 out: 65 hdr.result = ret; 66 hdr.size = min_t(size_t, usize, res_size); 67 68 if (copy_struct_to_user(udata, usize, data, hdr.size, NULL)) 69 return -EFAULT; 70 if (copy_to_user(uhdr, &hdr, sizeof(hdr))) 71 return -EFAULT; 72 *next_entry = hdr.next_entry; 73 return 0; 74 } 75 76 int io_query(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args) 77 { 78 char entry_buffer[IO_MAX_QUERY_SIZE]; 79 void __user *uhdr = arg; 80 int ret, nr = 0; 81 82 memset(entry_buffer, 0, sizeof(entry_buffer)); 83 84 if (nr_args) 85 return -EINVAL; 86 87 while (uhdr) { 88 u64 next_hdr; 89 90 ret = io_handle_query_entry(ctx, entry_buffer, uhdr, &next_hdr); 91 if (ret) 92 return ret; 93 uhdr = u64_to_user_ptr(next_hdr); 94 95 /* Have some limit to avoid a potential cycle */ 96 if (++nr >= IO_MAX_QUERY_ENTRIES) 97 return -ERANGE; 98 if (fatal_signal_pending(current)) 99 return -EINTR; 100 cond_resched(); 101 } 102 return 0; 103 } 104