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Annotation of coherent/g/usr/lib/uucp/tay104/unix/access.c, revision 1.1

1.1     ! root        1: /* access.c
        !             2:    Check access to files by the user and by the daemon.  */
        !             3: 
        !             4: #include "uucp.h"
        !             5: 
        !             6: #include "uudefs.h"
        !             7: #include "sysdep.h"
        !             8: #include "system.h"
        !             9: 
        !            10: #include <errno.h>
        !            11: 
        !            12: /* See if the user has access to a file, to prevent the setuid uucp
        !            13:    and uux programs handing out unauthorized access.  */
        !            14: 
        !            15: boolean
        !            16: fsysdep_access (zfile)
        !            17:      const char *zfile;
        !            18: {
        !            19:   if (access (zfile, R_OK) == 0)
        !            20:     return TRUE;
        !            21:   ulog (LOG_ERROR, "%s: %s", zfile, strerror (errno));
        !            22:   return FALSE;
        !            23: }
        !            24: 
        !            25: /* See if the daemon has access to a file.  This is called if a file
        !            26:    is not being transferred to the spool directory, since if the
        !            27:    daemon does not have access the later transfer will fail.  We
        !            28:    assume that the daemon will have the same euid (or egid) as the one
        !            29:    we are running under.  If our uid (gid) and euid (egid) are the
        !            30:    same, we assume that we have access.  Note that is not important
        !            31:    for security, since the check will be (implicitly) done again when
        !            32:    the daemon tries to transfer the file.  This routine should work
        !            33:    whether the UUCP programs are installed setuid or setgid.  */
        !            34: 
        !            35: boolean
        !            36: fsysdep_daemon_access (zfile)
        !            37:      const char *zfile;
        !            38: {
        !            39:   struct stat s;
        !            40:   uid_t ieuid, iuid, iegid, igid;
        !            41:   boolean fok;
        !            42: 
        !            43:   ieuid = geteuid ();
        !            44:   if (ieuid == 0)
        !            45:     return TRUE;
        !            46:   iuid = getuid ();
        !            47:   iegid = getegid ();
        !            48:   igid = getgid ();
        !            49: 
        !            50:   /* If our effective uid and gid are the same as our real uid and
        !            51:      gid, we assume the daemon will have access to the file.  */
        !            52:   if (ieuid == iuid && iegid == igid)
        !            53:     return TRUE;
        !            54: 
        !            55:  if (stat ((char *) zfile, &s) != 0)
        !            56:      {
        !            57:       ulog (LOG_ERROR, "stat (%s): %s", zfile, strerror (errno));
        !            58:       return FALSE;
        !            59:     }
        !            60: 
        !            61:   /* If our euid is not our uid, but it is the file's uid, see if the
        !            62:      owner has read access.  Otherwise, if our egid is not our gid,
        !            63:      but it is the file's gid, see if the group has read access.
        !            64:      Otherwise, see if the world has read access.  We know from the
        !            65:      above check that at least one of our euid and egid are different,
        !            66:      so that is the only one we want to check.  This check could fail
        !            67:      if the UUCP programs were both setuid and setgid, but why would
        !            68:      they be?  */
        !            69:   if (ieuid != iuid && ieuid == s.st_uid)
        !            70:     fok = (s.st_mode & S_IRUSR) != 0;
        !            71:   else if (iegid != igid && iegid == s.st_gid)
        !            72:     fok = (s.st_mode & S_IRGRP) != 0;
        !            73:   else
        !            74:     fok = (s.st_mode & S_IROTH) != 0;
        !            75: 
        !            76:   if (! fok)
        !            77:     {
        !            78:       ulog (LOG_ERROR, "%s: cannot be read by daemon", zfile);
        !            79:       return FALSE;
        !            80:     }
        !            81: 
        !            82:   return TRUE;
        !            83: }

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