| 1 | /* This file handles the 4 system calls that get and set uids and gids.
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| 2 | * It also handles getpid(), setsid(), and getpgrp(). The code for each
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| 3 | * one is so tiny that it hardly seemed worthwhile to make each a separate
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| 4 | * function.
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| 5 | */
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| 6 |
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| 7 | #include "pm.h"
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| 8 | #include <minix/callnr.h>
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| 9 | #include <signal.h>
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| 10 | #include "mproc.h"
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| 11 | #include "param.h"
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| 12 |
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| 13 | /*===========================================================================*
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| 14 | * do_getset *
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| 15 | *===========================================================================*/
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| 16 | PUBLIC int do_getset()
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| 17 | {
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| 18 | /* Handle GETUID, GETGID, GETPID, GETPGRP, SETUID, SETGID, SETSID. The four
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| 19 | * GETs and SETSID return their primary results in 'r'. GETUID, GETGID, and
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| 20 | * GETPID also return secondary results (the effective IDs, or the parent
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| 21 | * process ID) in 'reply_res2', which is returned to the user.
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| 22 | */
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| 23 |
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| 24 | register struct mproc *rmp = mp;
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| 25 | register int r;
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| 26 |
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| 27 | switch(call_nr) {
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| 28 | case GETUID:
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| 29 | r = rmp->mp_realuid;
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| 30 | rmp->mp_reply.reply_res2 = rmp->mp_effuid;
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| 31 | break;
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| 32 |
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| 33 | case GETGID:
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| 34 | r = rmp->mp_realgid;
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| 35 | rmp->mp_reply.reply_res2 = rmp->mp_effgid;
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| 36 | break;
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| 37 |
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| 38 | case GETPID:
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| 39 | r = mproc[who].mp_pid;
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| 40 | rmp->mp_reply.reply_res2 = mproc[rmp->mp_parent].mp_pid;
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| 41 | break;
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| 42 |
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| 43 | case SETUID:
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| 44 | if (rmp->mp_realuid != (uid_t) m_in.usr_id &&
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| 45 | rmp->mp_effuid != SUPER_USER)
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| 46 | return(EPERM);
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| 47 | rmp->mp_realuid = (uid_t) m_in.usr_id;
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| 48 | rmp->mp_effuid = (uid_t) m_in.usr_id;
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| 49 | tell_fs(SETUID, who, rmp->mp_realuid, rmp->mp_effuid);
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| 50 | r = OK;
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| 51 | break;
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| 52 |
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| 53 | case SETGID:
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| 54 | if (rmp->mp_realgid != (gid_t) m_in.grp_id &&
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| 55 | rmp->mp_effuid != SUPER_USER)
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| 56 | return(EPERM);
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| 57 | rmp->mp_realgid = (gid_t) m_in.grp_id;
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| 58 | rmp->mp_effgid = (gid_t) m_in.grp_id;
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| 59 | tell_fs(SETGID, who, rmp->mp_realgid, rmp->mp_effgid);
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| 60 | r = OK;
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| 61 | break;
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| 62 |
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| 63 | case SETSID:
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| 64 | if (rmp->mp_procgrp == rmp->mp_pid) return(EPERM);
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| 65 | rmp->mp_procgrp = rmp->mp_pid;
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| 66 | tell_fs(SETSID, who, 0, 0);
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| 67 | /* fall through */
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| 68 |
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| 69 | case GETPGRP:
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| 70 | r = rmp->mp_procgrp;
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| 71 | break;
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| 72 |
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| 73 | default:
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| 74 | r = EINVAL;
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| 75 | break;
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| 76 | }
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| 77 | return(r);
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| 78 | }
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