1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright Amazon.com Inc. or its affiliates. */
3 
4 #define _GNU_SOURCE
5 #include <sched.h>
6 
7 #include <unistd.h>
8 #include <linux/netlink.h>
9 #include <linux/rtnetlink.h>
10 #include <linux/sock_diag.h>
11 #include <linux/unix_diag.h>
12 #include <sys/socket.h>
13 #include <sys/stat.h>
14 #include <sys/types.h>
15 #include <sys/un.h>
16 
17 #include "../../kselftest_harness.h"
18 
19 FIXTURE(diag_uid)
20 {
21 	int netlink_fd;
22 	int unix_fd;
23 	__u32 inode;
24 	__u64 cookie;
25 };
26 
27 FIXTURE_VARIANT(diag_uid)
28 {
29 	int unshare;
30 	int udiag_show;
31 };
32 
33 FIXTURE_VARIANT_ADD(diag_uid, uid)
34 {
35 	.unshare = 0,
36 	.udiag_show = UDIAG_SHOW_UID
37 };
38 
39 FIXTURE_VARIANT_ADD(diag_uid, uid_unshare)
40 {
41 	.unshare = CLONE_NEWUSER,
42 	.udiag_show = UDIAG_SHOW_UID
43 };
44 
45 FIXTURE_SETUP(diag_uid)
46 {
47 	struct stat file_stat;
48 	socklen_t optlen;
49 	int ret;
50 
51 	if (variant->unshare)
52 		ASSERT_EQ(unshare(variant->unshare), 0);
53 
54 	self->netlink_fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_SOCK_DIAG);
55 	ASSERT_NE(self->netlink_fd, -1);
56 
57 	self->unix_fd = socket(AF_UNIX, SOCK_STREAM, 0);
58 	ASSERT_NE(self->unix_fd, -1);
59 
60 	ret = fstat(self->unix_fd, &file_stat);
61 	ASSERT_EQ(ret, 0);
62 
63 	self->inode = file_stat.st_ino;
64 
65 	optlen = sizeof(self->cookie);
66 	ret = getsockopt(self->unix_fd, SOL_SOCKET, SO_COOKIE, &self->cookie, &optlen);
67 	ASSERT_EQ(ret, 0);
68 }
69 
70 FIXTURE_TEARDOWN(diag_uid)
71 {
72 	close(self->netlink_fd);
73 	close(self->unix_fd);
74 }
75 
76 int send_request(struct __test_metadata *_metadata,
77 		 FIXTURE_DATA(diag_uid) *self,
78 		 const FIXTURE_VARIANT(diag_uid) *variant)
79 {
80 	struct {
81 		struct nlmsghdr nlh;
82 		struct unix_diag_req udr;
83 	} req = {
84 		.nlh = {
85 			.nlmsg_len = sizeof(req),
86 			.nlmsg_type = SOCK_DIAG_BY_FAMILY,
87 			.nlmsg_flags = NLM_F_REQUEST
88 		},
89 		.udr = {
90 			.sdiag_family = AF_UNIX,
91 			.udiag_ino = self->inode,
92 			.udiag_cookie = {
93 				(__u32)self->cookie,
94 				(__u32)(self->cookie >> 32)
95 			},
96 			.udiag_show = variant->udiag_show
97 		}
98 	};
99 	struct sockaddr_nl nladdr = {
100 		.nl_family = AF_NETLINK
101 	};
102 	struct iovec iov = {
103 		.iov_base = &req,
104 		.iov_len = sizeof(req)
105 	};
106 	struct msghdr msg = {
107 		.msg_name = &nladdr,
108 		.msg_namelen = sizeof(nladdr),
109 		.msg_iov = &iov,
110 		.msg_iovlen = 1
111 	};
112 
113 	return sendmsg(self->netlink_fd, &msg, 0);
114 }
115 
116 void render_response(struct __test_metadata *_metadata,
117 		     struct unix_diag_req *udr, __u32 len)
118 {
119 	unsigned int rta_len = len - NLMSG_LENGTH(sizeof(*udr));
120 	struct rtattr *attr;
121 	uid_t uid;
122 
123 	ASSERT_GT(len, sizeof(*udr));
124 	ASSERT_EQ(udr->sdiag_family, AF_UNIX);
125 
126 	attr = (struct rtattr *)(udr + 1);
127 	ASSERT_NE(RTA_OK(attr, rta_len), 0);
128 	ASSERT_EQ(attr->rta_type, UNIX_DIAG_UID);
129 
130 	uid = *(uid_t *)RTA_DATA(attr);
131 	ASSERT_EQ(uid, getuid());
132 }
133 
134 void receive_response(struct __test_metadata *_metadata,
135 		      FIXTURE_DATA(diag_uid) *self)
136 {
137 	long buf[8192 / sizeof(long)];
138 	struct sockaddr_nl nladdr = {
139 		.nl_family = AF_NETLINK
140 	};
141 	struct iovec iov = {
142 		.iov_base = buf,
143 		.iov_len = sizeof(buf)
144 	};
145 	struct msghdr msg = {
146 		.msg_name = &nladdr,
147 		.msg_namelen = sizeof(nladdr),
148 		.msg_iov = &iov,
149 		.msg_iovlen = 1
150 	};
151 	struct nlmsghdr *nlh;
152 	int ret;
153 
154 	ret = recvmsg(self->netlink_fd, &msg, 0);
155 	ASSERT_GT(ret, 0);
156 
157 	nlh = (struct nlmsghdr *)buf;
158 	ASSERT_NE(NLMSG_OK(nlh, ret), 0);
159 	ASSERT_EQ(nlh->nlmsg_type, SOCK_DIAG_BY_FAMILY);
160 
161 	render_response(_metadata, NLMSG_DATA(nlh), nlh->nlmsg_len);
162 
163 	nlh = NLMSG_NEXT(nlh, ret);
164 	ASSERT_EQ(NLMSG_OK(nlh, ret), 0);
165 }
166 
167 TEST_F(diag_uid, 1)
168 {
169 	int ret;
170 
171 	ret = send_request(_metadata, self, variant);
172 	ASSERT_GT(ret, 0);
173 
174 	receive_response(_metadata, self);
175 }
176 
177 TEST_HARNESS_MAIN
178