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Commit | Line | Data |
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ccbe9281 MT |
1 | |
2 | #include <errno.h> | |
3 | #include <fcntl.h> | |
4 | #include <signal.h> | |
5 | #include <stdio.h> | |
6 | #include <stdlib.h> | |
7 | #include <string.h> | |
8 | #include <syslog.h> | |
9 | #include <unistd.h> | |
10 | ||
11 | #include <sys/types.h> | |
12 | #include <sys/stat.h> | |
13 | ||
14 | void alarm_handler(int num) { | |
15 | return; | |
16 | } | |
17 | ||
18 | int open_and_lock_securetty() { | |
19 | int fd; | |
20 | struct flock lock; | |
21 | struct sigaction act, oldact; | |
22 | ||
23 | lock.l_type = F_WRLCK; | |
24 | lock.l_whence = SEEK_SET; | |
25 | lock.l_start = 0; | |
26 | lock.l_len = 0; | |
27 | ||
28 | fd = open("/etc/securetty", O_RDWR); | |
29 | if (fd == -1) { | |
30 | syslog(LOG_ERR, "Couldn't open /etc/securetty: %s",strerror(errno)); | |
31 | return -1; | |
32 | } | |
33 | act.sa_handler = alarm_handler; | |
34 | act.sa_flags = 0; | |
35 | sigaction(SIGALRM, &act, &oldact); | |
36 | alarm(2); | |
37 | while (fcntl(fd, F_SETLKW, &lock) == -1) { | |
38 | if (errno == EINTR) { | |
39 | syslog(LOG_ERR, "Couldn't lock /etc/securetty: Timeout exceeded"); | |
40 | } else { | |
41 | syslog(LOG_ERR, "Couldn't lock /etc/securetty: %s",strerror(errno)); | |
42 | } | |
43 | return -1; | |
44 | } | |
45 | alarm(0); | |
46 | sigaction(SIGALRM, &oldact, NULL); | |
47 | return fd; | |
48 | } | |
49 | ||
50 | int rewrite_securetty(char *terminal) { | |
51 | int fd; | |
52 | char *buf, *pos; | |
53 | struct stat sbuf; | |
54 | ||
55 | fd = open_and_lock_securetty(); | |
56 | if (fd == -1) | |
57 | return 1; | |
58 | if (fstat(fd, &sbuf) == -1) { | |
59 | close(fd); | |
60 | syslog(LOG_ERR, "Couldn't stat /etc/securetty: %s",strerror(errno)); | |
61 | return 1; | |
62 | } | |
63 | buf = malloc(sbuf.st_size + 1); | |
64 | if (read(fd, buf, sbuf.st_size) != sbuf.st_size) { | |
65 | close(fd); | |
66 | syslog(LOG_ERR, "Couldn't read /etc/securetty: %s",strerror(errno)); | |
67 | return 1; | |
68 | } | |
69 | if (!strncmp(buf,terminal,strlen(terminal)) && buf[strlen(terminal)] == '\n') | |
70 | goto out_ok; | |
71 | if ((pos = strstr(buf, terminal))) { | |
72 | if (pos[strlen(terminal)] == '\n' && *(pos-1) == '\n') | |
73 | goto out_ok; | |
74 | } | |
75 | if (lseek(fd, 0, SEEK_END) == -1) { | |
76 | close(fd); | |
77 | syslog(LOG_ERR, "Couldn't seek to end of /etc/securetty: %s",strerror(errno)); | |
78 | return 1; | |
79 | } | |
80 | write(fd, terminal, strlen(terminal)); | |
81 | write(fd, "\n", 1); | |
82 | out_ok: | |
83 | close(fd); | |
84 | return 0; | |
85 | } | |
86 | ||
87 | int main(int argc, char **argv) { | |
88 | if (argc < 2 ) { | |
89 | fprintf(stderr, "Usage: securetty <device>\n"); | |
90 | exit(1); | |
91 | } | |
92 | openlog("securetty", LOG_CONS, LOG_DAEMON); | |
93 | return rewrite_securetty(argv[1]); | |
94 | } |