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| 25 | |
25 | |
| 26 | #include "../config.h" |
26 | #include "../config.h" |
| 27 | |
27 | |
| 28 | #include "ptytty.h" |
28 | #include "ptytty.h" |
| 29 | |
29 | |
| 30 | // helper/proxy support |
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| 31 | |
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| 32 | #if PTYTTY_HELPER |
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| 33 | |
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| 34 | #include <csignal> |
30 | #include <csignal> |
| 35 | |
31 | |
| 36 | #include <sys/types.h> |
32 | #include <sys/types.h> |
| 37 | #include <sys/socket.h> |
33 | #include <sys/socket.h> |
| 38 | #include <unistd.h> |
34 | #include <unistd.h> |
| 39 | #include <fcntl.h> |
35 | #include <fcntl.h> |
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36 | #include <errno.h> |
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37 | |
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38 | // helper/proxy support |
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39 | |
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40 | #if PTYTTY_HELPER |
| 40 | |
41 | |
| 41 | static int sock_fd = -1, lock_fd = -1; |
42 | static int sock_fd = -1, lock_fd = -1; |
| 42 | static int helper_pid, owner_pid; |
43 | static int helper_pid, owner_pid; |
| 43 | |
44 | |
| 44 | struct command |
45 | struct command |
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| 123 | |
124 | |
| 124 | ptytty_proxy::~ptytty_proxy () |
125 | ptytty_proxy::~ptytty_proxy () |
| 125 | { |
126 | { |
| 126 | if (id) |
127 | if (id) |
| 127 | { |
128 | { |
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129 | close_tty (); |
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130 | |
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131 | if (pty >= 0) |
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132 | close (pty); |
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133 | |
| 128 | NEED_TOKEN; |
134 | NEED_TOKEN; |
| 129 | |
135 | |
| 130 | command cmd; |
136 | command cmd; |
| 131 | |
137 | |
| 132 | cmd.type = command::destroy; |
138 | cmd.type = command::destroy; |
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| 290 | #endif |
296 | #endif |
| 291 | return new ptytty_unix; |
297 | return new ptytty_unix; |
| 292 | } |
298 | } |
| 293 | |
299 | |
| 294 | void |
300 | void |
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301 | ptytty::sanitise_stdfd () |
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302 | { |
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303 | // sanitise stdin/stdout/stderr to point to *something*. |
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304 | for (int fd = 0; fd <= 2; ++fd) |
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305 | if (fcntl (fd, F_GETFL) < 0 && errno == EBADF) |
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306 | { |
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307 | int fd2 = open ("/dev/tty", fd ? O_WRONLY : O_RDONLY); |
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308 | |
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309 | if (fd2 < 0) |
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310 | fd2 = open ("/dev/null", fd ? O_WRONLY : O_RDONLY); |
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311 | |
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312 | if (fd2 != fd) |
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313 | abort (); |
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314 | } |
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315 | } |
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316 | |
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317 | void |
| 295 | ptytty::init () |
318 | ptytty::init () |
| 296 | { |
319 | { |
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320 | sanitise_stdfd (); |
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321 | |
| 297 | uid_t uid = getuid (); |
322 | uid_t uid = getuid (); |
| 298 | gid_t gid = getgid (); |
323 | gid_t gid = getgid (); |
| 299 | |
324 | |
| 300 | // before doing anything else, check for setuid/setgid operation, |
325 | // before doing anything else, check for setuid/setgid operation, |
| 301 | // start the helper process and drop privileges |
326 | // start the helper process and drop privileges |
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| 303 | || gid != getegid ()) |
328 | || gid != getegid ()) |
| 304 | { |
329 | { |
| 305 | #if PTYTTY_HELPER |
330 | #if PTYTTY_HELPER |
| 306 | use_helper (); |
331 | use_helper (); |
| 307 | #else |
332 | #else |
| 308 | ptytty_warn ("running setuid/setgid without pty helper compiled in, continuing unprivileged.\n"); |
333 | ptytty_warn ("running setuid/setgid without pty helper compiled in, continuing unprivileged.\n", 0); |
| 309 | #endif |
334 | #endif |
| 310 | |
335 | |
| 311 | drop_privileges (); |
336 | drop_privileges (); |
| 312 | } |
337 | } |
| 313 | } |
338 | } |
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| 326 | setregid (gid, gid); |
351 | setregid (gid, gid); |
| 327 | setreuid (uid, uid); |
352 | setreuid (uid, uid); |
| 328 | #elif HAVE_SETUID |
353 | #elif HAVE_SETUID |
| 329 | setgid (gid); |
354 | setgid (gid); |
| 330 | setuid (uid); |
355 | setuid (uid); |
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356 | #else |
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357 | # error no way to drop privileges, configure failed? |
| 331 | #endif |
358 | #endif |
| 332 | |
359 | |
| 333 | if (uid != geteuid () |
360 | if (uid != geteuid () |
| 334 | || gid != getegid ()) |
361 | || gid != getegid ()) |
| 335 | ptytty_fatal ("unable to drop privileges, aborting.\n"); |
362 | ptytty_fatal ("unable to drop privileges, aborting.\n"); |
