src/port/getpeereid.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * getpeereid.c
   4  *              get peer userid for UNIX-domain socket connection
   5  *
   6  * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
   7  *
   8  *
   9  * IDENTIFICATION
  10  *        src/port/getpeereid.c
  11  *
  12  *-------------------------------------------------------------------------
  13  */
  14
  15 #include "c.h"
  16
  17 #include <sys/param.h>
  18 #include <sys/socket.h>
  19 #include <unistd.h>
  20 #ifdef HAVE_SYS_UN_H
  21 #include <sys/un.h>
  22 #endif
  23 #ifdef HAVE_UCRED_H
  24 #include <ucred.h>
  25 #endif
  26 #ifdef HAVE_SYS_UCRED_H
  27 #include <sys/ucred.h>
  28 #endif
  29
  30
  31 /*
  32  * BSD-style getpeereid() for platforms that lack it.
  33  */
  34 int
  35 getpeereid(int sock, uid_t *uid, gid_t *gid)
  36 {
  37 #if defined(SO_PEERCRED)
  38         /* Linux: use getsockopt(SO_PEERCRED) */
  39         struct ucred peercred;
  40         ACCEPT_TYPE_ARG3 so_len = sizeof(peercred);
  41
  42         if (getsockopt(sock, SOL_SOCKET, SO_PEERCRED, &peercred, &so_len) != 0 ||
  43                 so_len != sizeof(peercred))
  44                 return -1;
  45         *uid = peercred.uid;
  46         *gid = peercred.gid;
  47         return 0;
  48 #elif defined(LOCAL_PEERCRED)
  49         /* Debian with FreeBSD kernel: use getsockopt(LOCAL_PEERCRED) */
  50         struct xucred peercred;
  51         ACCEPT_TYPE_ARG3 so_len = sizeof(peercred);
  52
  53         if (getsockopt(sock, 0, LOCAL_PEERCRED, &peercred, &so_len) != 0 ||
  54                 so_len != sizeof(peercred) ||
  55                 peercred.cr_version != XUCRED_VERSION)
  56                 return -1;
  57         *uid = peercred.cr_uid;
  58         *gid = peercred.cr_gid;
  59         return 0;
  60 #elif defined(HAVE_GETPEERUCRED)
  61         /* Solaris: use getpeerucred() */
  62         ucred_t    *ucred;
  63
  64         ucred = NULL;                           /* must be initialized to NULL */
  65         if (getpeerucred(sock, &ucred) == -1)
  66                 return -1;
  67
  68         *uid = ucred_geteuid(ucred);
  69         *gid = ucred_getegid(ucred);
  70         ucred_free(ucred);
  71
  72         if (*uid == (uid_t) (-1) || *gid == (gid_t) (-1))
  73                 return -1;
  74         return 0;
  75 #else
  76         /* No implementation available on this platform */
  77         errno = ENOSYS;
  78         return -1;
  79 #endif
  80 }