1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
|
/* ISC license. */
#include <string.h>
#include <stdint.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <skalibs/types.h>
#include <skalibs/allreadwrite.h>
#include <skalibs/sgetopt.h>
#include <skalibs/bytestr.h>
#include <skalibs/buffer.h>
#include <skalibs/stralloc.h>
#include <skalibs/strerr.h>
#include <skalibs/tai.h>
#include <skalibs/iopause.h>
#include <skalibs/selfpipe.h>
#include <skalibs/env.h>
#include <skalibs/cspawn.h>
#include <skalibs/djbunix.h>
#include <skalibs/unix-timed.h>
#include <skalibs/unixmessage.h>
#include "s6-sudo.h"
#define USAGE "s6-sudod [ -0 ] [ -1 ] [ -2 ] [ -d ] [ -t timeout ] args..."
#define dieusage() strerr_dieusage(100, USAGE)
#define dienomem() strerr_diefu1sys(111, "stralloc_catb")
static int handle_signals (pid_t pid, int *wstat)
{
int done = 0 ;
for (;;)
{
int sig = selfpipe_read() ;
switch (sig)
{
case -1 : strerr_diefu1sys(111, "read from selfpipe") ;
case 0 : return done ;
case SIGCHLD :
{
int w ;
pid_t r = wait_pid_nohang(pid, &w) ;
if ((r < 0) && (errno != ECHILD))
strerr_diefu1sys(111, "wait_pid_nohang") ;
else if (r > 0)
{
done = 1 ;
*wstat = w ;
}
break ;
}
default :
strerr_dief1sys(101, "internal inconsistency, please submit a bug-report") ;
}
}
}
int main (int argc, char const *const *argv, char const *const *envp)
{
iopause_fd x[2] = { { .events = IOPAUSE_READ }, { .fd = 0, .events = 0, .revents = 0 } } ;
unixmessage m ;
unsigned int nullfds = 0 ;
pid_t pid ;
int wstat ;
size_t envc = env_len(envp) ;
uint32_t cargc, cenvc, carglen, cenvlen ;
tain deadline = TAIN_INFINITE_RELATIVE ;
PROG = "s6-sudod" ;
{
subgetopt l = SUBGETOPT_ZERO ;
unsigned int t = 0 ;
for (;;)
{
int opt = subgetopt_r(argc, argv, "012dt:", &l) ;
if (opt < 0) break ;
switch (opt)
{
case '0' : nullfds |= 1 ; break ;
case '1' : nullfds |= 2 ; break ;
case '2' : nullfds |= 4 ; break ;
case 'd' : nullfds |= 15 ; break ;
case 't' : if (!uint0_scan(l.arg, &t)) dieusage() ; break ;
default : dieusage() ;
}
}
argc -= l.ind ; argv += l.ind ;
if (t) tain_from_millisecs(&deadline, t) ;
}
if ((ndelay_on(0) < 0) || (ndelay_on(1) < 0))
strerr_diefu1sys(111, "make socket non-blocking") ;
tain_now_set_stopwatch_g() ;
tain_add_g(&deadline, &deadline) ;
buffer_putnoflush(buffer_1small, S6_SUDO_BANNERB, S6_SUDO_BANNERB_LEN) ;
if (!buffer_timed_flush_g(buffer_1small, &deadline))
strerr_diefu1sys(111, "write banner to client") ;
if (unixmessage_timed_receive_g(unixmessage_receiver_0, &m, &deadline) <= 0)
strerr_diefu1sys(111, "read message from client") ;
if (m.nfds != 3)
strerr_dief1x(100, "client did not send 3 fds") ;
if (m.len < 16 + S6_SUDO_BANNERA_LEN)
strerr_dief1x(100, "wrong client message") ;
if (strncmp(m.s, S6_SUDO_BANNERA, S6_SUDO_BANNERA_LEN))
strerr_dief1x(100, "wrong client banner") ;
uint32_unpack_big(m.s + S6_SUDO_BANNERA_LEN, &cargc) ;
uint32_unpack_big(m.s + S6_SUDO_BANNERA_LEN + 4, &cenvc) ;
uint32_unpack_big(m.s + S6_SUDO_BANNERA_LEN + 8, &carglen) ;
uint32_unpack_big(m.s + S6_SUDO_BANNERA_LEN + 12, &cenvlen) ;
if (S6_SUDO_BANNERA_LEN + 16 + carglen + cenvlen != m.len)
strerr_dief1x(100, "wrong client argc/envlen") ;
if ((cargc > 131072) || (cenvc > 131072))
strerr_dief1x(100, "too many args/envvars from client") ;
if (argc + cargc == 0) strerr_dief1x(100, "client and server args both empty") ;
if (nullfds & 1)
{
close(m.fds[0]) ;
m.fds[0] = open2("/dev/null", O_RDONLY) ;
if (m.fds[0] < 0) strerr_diefu2sys(111, "open /dev/null for ", "reading") ;
}
if (nullfds & 2)
{
close(m.fds[1]) ;
m.fds[1] = open2("/dev/null", O_WRONLY) ;
if (m.fds[1] < 0) strerr_diefu2sys(111, "open /dev/null for ", "writing") ;
}
if (nullfds & 4)
{
close(m.fds[2]) ;
m.fds[2] = 2 ;
}
{
cspawn_fileaction fa[3] =
{
[0] = { .type = CSPAWN_FA_MOVE, .x = { .fd2 = { [0] = 0, [1] = m.fds[0] } } },
[1] = { .type = CSPAWN_FA_MOVE, .x = { .fd2 = { [0] = 1, [1] = m.fds[1] } } },
[2] = { .type = CSPAWN_FA_MOVE, .x = { .fd2 = { [0] = 2, [1] = m.fds[2] } } }
} ;
char const *targv[argc + 1 + cargc] ;
char const *tenvp[envc + 1 + cenvc] ;
unsigned int i = 0 ;
for (; i < (unsigned int)argc ; i++) targv[i] = argv[i] ;
for (i = 0 ; i <= envc ; i++) tenvp[i] = envp[i] ;
if (!env_make(targv + argc, cargc, m.s + S6_SUDO_BANNERA_LEN + 16, carglen))
{
char c = errno ;
buffer_putnoflush(buffer_1small, &c, 1) ;
buffer_timed_flush_g(buffer_1small, &deadline) ;
errno = c ;
strerr_diefu1sys(111, "make child argv") ;
}
if (!env_make(tenvp + envc + 1, cenvc, m.s + S6_SUDO_BANNERA_LEN + 16 + carglen, cenvlen))
{
char c = errno ;
buffer_putnoflush(buffer_1small, &c, 1) ;
buffer_timed_flush_g(buffer_1small, &deadline) ;
errno = c ;
strerr_diefu1sys(111, "make child envp") ;
}
targv[argc + cargc] = 0 ;
for (i = 0 ; i < cenvc ; i++)
{
char const *var = tenvp[envc + 1 + i] ;
unsigned int j = 0 ;
size_t len = str_chr(var, '=') ;
if (!var[len])
{
char c = EINVAL ;
buffer_putnoflush(buffer_1small, &c, 1) ;
buffer_timed_flush_g(buffer_1small, &deadline) ;
strerr_dief1x(100, "bad environment from client") ;
}
for (; j < envc ; j++) if (!strncmp(var, tenvp[j], len+1)) break ;
if ((j < envc) && !tenvp[j][len+1]) tenvp[j] = var ;
}
x[0].fd = selfpipe_init() ;
if (x[0].fd < 0) strerr_diefu1sys(111, "selfpipe_init") ;
if (!selfpipe_trap(SIGCHLD)) strerr_diefu1sys(111, "trap SIGCHLD") ;
pid = cspawn(targv[0], targv, tenvp, CSPAWN_FLAGS_SELFPIPE_FINISH, fa, 3) ;
if (!pid) strerr_diefu2sys(111, "spawn ", targv[0]) ;
}
fd_close(m.fds[0]) ;
fd_close(m.fds[1]) ;
if (!(nullfds & 4)) fd_close(m.fds[2]) ;
unixmessage_receiver_free(unixmessage_receiver_0) ;
buffer_putnoflush(buffer_1small, "", 1) ;
if (!buffer_timed_flush_g(buffer_1small, &deadline))
strerr_diefu1sys(111, "send confirmation to client") ;
for (;;)
{
if (iopause_g(x, 1 + !x[1].revents, 0) < 0) strerr_diefu1sys(111, "iopause") ;
if (x[0].revents && handle_signals(pid, &wstat)) break ;
if (x[1].revents && !(nullfds & 8))
{
kill(pid, SIGTERM) ;
kill(pid, SIGCONT) ;
return 1 ;
}
}
if (!x[1].revents)
{
char pack[UINT_PACK] ;
uint_pack_big(pack, (unsigned int)wstat) ;
buffer_putnoflush(buffer_1small, pack, UINT_PACK) ;
if (ndelay_off(1) < 0)
strerr_diefu1sys(111, "set stdout blocking") ;
if (!buffer_flush(buffer_1small))
strerr_diefu1sys(111, "write status to client") ;
}
return 0 ;
}
|
