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
io_query_ops(void * data)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
io_handle_query_entry(struct io_ring_ctx * ctx,void * data,void __user * uhdr,u64 * next_entry)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
io_query(struct io_ring_ctx * ctx,void __user * arg,unsigned nr_args)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