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
11static 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
26static 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(to: &hdr, from: uhdr, n: 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(s: hdr.__resv, n: sizeof(hdr.__resv)) || hdr.result || !hdr.size)
46 goto out;
47 if (copy_from_user(to: data, from: udata, n: 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 }
62out:
63 hdr.result = ret;
64 hdr.size = min_t(size_t, usize, res_size);
65
66 if (copy_struct_to_user(dst: udata, usize, src: data, ksize: hdr.size, NULL))
67 return -EFAULT;
68 if (copy_to_user(to: uhdr, from: &hdr, n: sizeof(hdr)))
69 return -EFAULT;
70 *next_entry = hdr.next_entry;
71 return 0;
72}
73
74int 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(s: entry_buffer, c: 0, n: 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, data: entry_buffer, uhdr, next_entry: &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