1 /*
2  *  Copyright (C) 2013-2022 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
3  *  Copyright (C) 2007-2013 Sourcefire, Inc.
4  *
5  *  Authors: Tomasz Kojm
6  *
7  *  This program is free software; you can redistribute it and/or modify
8  *  it under the terms of the GNU General Public License version 2 as
9  *  published by the Free Software Foundation.
10  *
11  *  This program is distributed in the hope that it will be useful,
12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *  GNU General Public License for more details.
15  *
16  *  You should have received a copy of the GNU General Public License
17  *  along with this program; if not, write to the Free Software
18  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
19  *  MA 02110-1301, USA.
20  */
21 
22 #if HAVE_CONFIG_H
23 #include "clamav-config.h"
24 #endif
25 
26 #include <stdio.h>
27 #include <string.h>
28 #include <sys/types.h>
29 #ifndef _WIN32
30 #include <sys/socket.h>
31 #include <sys/un.h>
32 #endif
33 #include <sys/stat.h>
34 #include <errno.h>
35 #ifdef HAVE_UNISTD_H
36 #include <unistd.h>
37 #endif
38 
39 // libclamav
40 #include "clamav.h"
41 #include "str.h"
42 
43 // common
44 #include "optparser.h"
45 #include "output.h"
46 #include "misc.h"
47 
48 #include "clamd_others.h"
49 #include "server.h"
50 #include "localserver.h"
51 
52 #ifdef _WIN32
localserver(const struct optstruct * opts)53 int localserver(const struct optstruct *opts)
54 {
55     logg("!Localserver is not supported on this platform");
56     return -1;
57 }
58 
59 #else
60 
localserver(const struct optstruct * opts)61 int localserver(const struct optstruct *opts)
62 {
63     struct sockaddr_un server;
64     int sockfd = 0, backlog;
65     STATBUF foo;
66     char *estr;
67     char *sockdir;
68     char *pos;
69     struct stat sb;
70     int cnt;
71 
72     int num_fd = sd_listen_fds(0);
73     if (num_fd > 2) {
74         logg("!LOCAL: Received more than two file descriptors from systemd.\n");
75         return -1;
76     } else if (num_fd > 0) {
77         /* use socket passed by systemd */
78         int i;
79         for (i = 0; i < num_fd; i += 1) {
80             sockfd = SD_LISTEN_FDS_START + i;
81             if (sd_is_socket(sockfd, AF_UNIX, SOCK_STREAM, 1) == 1) {
82                 /* correct socket */
83                 break;
84             } else {
85                 /* wrong socket */
86                 sockfd = -2;
87             }
88         }
89         if (sockfd == -2) {
90             logg("#LOCAL: No local AF_UNIX SOCK_STREAM socket received from systemd.\n");
91             return -2;
92         }
93         logg("#LOCAL: Received AF_UNIX SOCK_STREAM socket from systemd.\n");
94         return sockfd;
95     }
96     /* create socket */
97     memset((char *)&server, 0, sizeof(server));
98     server.sun_family = AF_UNIX;
99     strncpy(server.sun_path, optget(opts, "LocalSocket")->strarg, sizeof(server.sun_path));
100     server.sun_path[sizeof(server.sun_path) - 1] = '\0';
101 
102     pos = NULL;
103     if ((pos = strstr(server.sun_path, "/")) && (pos = strstr(((char *)pos + 1), "/"))) {
104         cnt     = 0;
105         sockdir = NULL;
106         pos     = server.sun_path + strlen(server.sun_path);
107         while (pos != server.sun_path) {
108             if (*pos == '/') {
109                 sockdir = CLI_STRNDUP(server.sun_path, strlen(server.sun_path) - cnt);
110                 break;
111             } else {
112                 pos--;
113                 cnt++;
114             }
115         }
116 
117         if (stat(sockdir, &sb)) {
118             if (errno == ENOENT) {
119                 mode_t old_umask;
120                 mode_t sock_mode;
121                 if (optget(opts, "LocalSocketMode")->enabled) {
122                     char *end;
123                     sock_mode = strtol(optget(opts, "LocalSocketMode")->strarg, &end, 8);
124 
125                     if (*end) {
126                         logg("!Invalid LocalSocketMode %s\n", optget(opts, "LocalSocketMode")->strarg);
127                         free(sockdir);
128                         return -1;
129                     }
130                 } else {
131                     sock_mode = 0777;
132                 }
133 
134                 old_umask = umask(0011); /* allow mode 777 for socket directory */
135                 if (mkdir(sockdir, sock_mode)) {
136                     logg("!LOCAL: Could not create socket directory: %s: %s\n", sockdir, strerror(errno));
137                     if (errno == ENOENT) {
138                         logg("!LOCAL: Ensure parent directory exists.\n");
139                     }
140                 } else {
141                     logg("Localserver: Creating socket directory: %s\n", sockdir);
142                 }
143                 umask(old_umask); /* restore umask */
144             }
145         }
146         free(sockdir);
147     }
148 
149     if ((sockfd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
150         estr = strerror(errno);
151         logg("!LOCAL: Socket allocation error: %s\n", estr);
152         return -1;
153     }
154 
155     if (bind(sockfd, (struct sockaddr *)&server, sizeof(struct sockaddr_un)) == -1) {
156         if (errno == EADDRINUSE) {
157             if (connect(sockfd, (struct sockaddr *)&server, sizeof(struct sockaddr_un)) >= 0) {
158                 logg("!LOCAL: Socket file %s is in use by another process.\n", server.sun_path);
159                 close(sockfd);
160                 return -1;
161             }
162             if (optget(opts, "FixStaleSocket")->enabled) {
163                 logg("#LOCAL: Removing stale socket file %s\n", server.sun_path);
164                 if (unlink(server.sun_path) == -1) {
165                     estr = strerror(errno);
166                     logg("!LOCAL: Socket file %s could not be removed: %s\n", server.sun_path, estr);
167                     close(sockfd);
168                     return -1;
169                 }
170                 if (bind(sockfd, (struct sockaddr *)&server, sizeof(struct sockaddr_un)) == -1) {
171                     estr = strerror(errno);
172                     logg("!LOCAL: Socket file %s could not be bound: %s (unlink tried)\n", server.sun_path, estr);
173                     close(sockfd);
174                     return -1;
175                 }
176             } else if (CLAMSTAT(server.sun_path, &foo) != -1) {
177                 logg("!LOCAL: Socket file %s exists. Either remove it, or configure a different one.\n", server.sun_path);
178                 close(sockfd);
179                 return -1;
180             }
181         } else {
182             estr = strerror(errno);
183             logg("!LOCAL: Socket file %s could not be bound: %s\n", server.sun_path, estr);
184             close(sockfd);
185             return -1;
186         }
187     }
188 
189     logg("#LOCAL: Unix socket file %s\n", server.sun_path);
190 
191     backlog = optget(opts, "MaxConnectionQueueLength")->numarg;
192     logg("#LOCAL: Setting connection queue length to %d\n", backlog);
193 
194     if (listen(sockfd, backlog) == -1) {
195         estr = strerror(errno);
196         logg("!LOCAL: listen() error: %s\n", estr);
197         close(sockfd);
198         return -1;
199     }
200 
201     return sockfd;
202 }
203 #endif
204