| 1 | /* Copyright (C) 1991-2024 Free Software Foundation, Inc. |
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| 2 | This file is part of the GNU C Library. |
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| 3 | |
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| 4 | The GNU C Library is free software; you can redistribute it and/or |
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| 5 | modify it under the terms of the GNU Lesser General Public |
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| 6 | License as published by the Free Software Foundation; either |
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| 7 | version 2.1 of the License, or (at your option) any later version. |
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| 8 | |
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| 9 | The GNU C Library is distributed in the hope that it will be useful, |
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| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 12 | Lesser General Public License for more details. |
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| 13 | |
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| 14 | You should have received a copy of the GNU Lesser General Public |
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| 15 | License along with the GNU C Library; if not, see |
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| 16 | <https://www.gnu.org/licenses/>. */ |
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| 17 | |
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| 18 | #include <errno.h> |
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| 19 | #include <unistd.h> |
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| 20 | #include <sys/types.h> |
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| 21 | #include <hurd.h> |
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| 22 | #include <hurd/id.h> |
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| 23 | #include <string.h> |
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| 24 | |
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| 25 | /* Set the group ID of the calling process to UID. |
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| 26 | If the calling process is the super-user, the real |
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| 27 | and effective group IDs, and the saved set-group-ID to UID; |
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| 28 | if not, the effective group ID is set to GID. */ |
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| 29 | int |
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| 30 | __setgid (gid_t gid) |
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| 31 | { |
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| 32 | auth_t newauth; |
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| 33 | error_t err; |
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| 34 | |
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| 35 | retry: |
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| 36 | HURD_CRITICAL_BEGIN; |
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| 37 | __mutex_lock (&_hurd_id.lock); |
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| 38 | err = _hurd_check_ids (); |
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| 39 | |
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| 40 | if (!err) |
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| 41 | { |
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| 42 | /* Make a new auth handle which has GID as the real gid, |
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| 43 | and as the first element in the list of effective gids. */ |
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| 44 | |
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| 45 | gid_t *newgen, *newaux, auxbuf[2]; |
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| 46 | size_t ngen, naux; |
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| 47 | |
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| 48 | if (_hurd_id.gen.ngids == 0) |
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| 49 | { |
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| 50 | /* No effective gids now. The new set will be just GID. */ |
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| 51 | newgen = &gid; |
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| 52 | ngen = 1; |
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| 53 | } |
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| 54 | else |
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| 55 | { |
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| 56 | _hurd_id.gen.gids[0] = gid; |
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| 57 | _hurd_id.valid = 0; |
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| 58 | newgen = _hurd_id.gen.gids; |
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| 59 | ngen = _hurd_id.gen.ngids; |
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| 60 | } |
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| 61 | |
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| 62 | newaux = _hurd_id.aux.gids; |
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| 63 | naux = _hurd_id.aux.ngids; |
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| 64 | if (_hurd_id.gen.nuids > 0 && _hurd_id.gen.uids[0] == 0) |
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| 65 | { |
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| 66 | /* We are root; set the real and saved IDs too. */ |
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| 67 | _hurd_id.valid = 0; |
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| 68 | if (_hurd_id.aux.ngids < 2) |
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| 69 | { |
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| 70 | newaux = auxbuf; |
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| 71 | naux = 2; |
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| 72 | } |
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| 73 | newaux[0] = newaux[1] = gid; |
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| 74 | } |
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| 75 | |
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| 76 | err = __USEPORT (AUTH, __auth_makeauth |
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| 77 | (port, NULL, MACH_MSG_TYPE_COPY_SEND, 0, |
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| 78 | _hurd_id.gen.uids, _hurd_id.gen.nuids, |
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| 79 | _hurd_id.aux.uids, _hurd_id.aux.nuids, |
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| 80 | newgen, ngen, newaux, naux, |
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| 81 | &newauth)); |
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| 82 | } |
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| 83 | __mutex_unlock (&_hurd_id.lock); |
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| 84 | HURD_CRITICAL_END; |
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| 85 | if (err == EINTR) |
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| 86 | /* Got a signal while inside an RPC of the critical section, retry again */ |
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| 87 | goto retry; |
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| 88 | |
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| 89 | if (err) |
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| 90 | return __hurd_fail (err); |
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| 91 | |
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| 92 | /* Install the new handle and reauthenticate everything. */ |
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| 93 | err = __setauth (newauth); |
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| 94 | __mach_port_deallocate (__mach_task_self (), newauth); |
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| 95 | return err; |
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| 96 | } |
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| 97 | |
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| 98 | weak_alias (__setgid, setgid) |
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| 99 | |
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