84 lines
2.4 KiB
C
84 lines
2.4 KiB
C
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/* access.c
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Check access to files by the user and by the daemon. */
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#include "uucp.h"
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#include "uudefs.h"
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#include "sysdep.h"
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#include "system.h"
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#include <errno.h>
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/* See if the user has access to a file, to prevent the setuid uucp
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and uux programs handing out unauthorized access. */
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boolean
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fsysdep_access (zfile)
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const char *zfile;
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{
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if (access (zfile, R_OK) == 0)
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return TRUE;
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ulog (LOG_ERROR, "%s: %s", zfile, strerror (errno));
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return FALSE;
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}
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/* See if the daemon has access to a file. This is called if a file
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is not being transferred to the spool directory, since if the
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daemon does not have access the later transfer will fail. We
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assume that the daemon will have the same euid (or egid) as the one
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we are running under. If our uid (gid) and euid (egid) are the
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same, we assume that we have access. Note that is not important
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for security, since the check will be (implicitly) done again when
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the daemon tries to transfer the file. This routine should work
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whether the UUCP programs are installed setuid or setgid. */
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boolean
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fsysdep_daemon_access (zfile)
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const char *zfile;
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{
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struct stat s;
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uid_t ieuid, iuid, iegid, igid;
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boolean fok;
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ieuid = geteuid ();
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if (ieuid == 0)
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return TRUE;
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iuid = getuid ();
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iegid = getegid ();
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igid = getgid ();
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/* If our effective uid and gid are the same as our real uid and
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gid, we assume the daemon will have access to the file. */
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if (ieuid == iuid && iegid == igid)
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return TRUE;
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if (stat ((char *) zfile, &s) != 0)
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{
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ulog (LOG_ERROR, "stat (%s): %s", zfile, strerror (errno));
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return FALSE;
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}
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/* If our euid is not our uid, but it is the file's uid, see if the
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owner has read access. Otherwise, if our egid is not our gid,
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but it is the file's gid, see if the group has read access.
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Otherwise, see if the world has read access. We know from the
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above check that at least one of our euid and egid are different,
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so that is the only one we want to check. This check could fail
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if the UUCP programs were both setuid and setgid, but why would
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they be? */
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if (ieuid != iuid && ieuid == s.st_uid)
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fok = (s.st_mode & S_IRUSR) != 0;
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else if (iegid != igid && iegid == s.st_gid)
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fok = (s.st_mode & S_IRGRP) != 0;
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else
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fok = (s.st_mode & S_IROTH) != 0;
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if (! fok)
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{
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ulog (LOG_ERROR, "%s: cannot be read by daemon", zfile);
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return FALSE;
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}
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return TRUE;
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}
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