src/port/getpeereid.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * getpeereid.c
   4  *              get peer userid for UNIX-domain socket connection
   5  *
   6  * Portions Copyright (c) 1996-2024, 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 <sys/un.h>
  20 #include <unistd.h>
  21 #ifdef HAVE_UCRED_H
  22 #include <ucred.h>
  23 #endif
  24 #ifdef HAVE_SYS_UCRED_H
  25 #include <sys/ucred.h>
  26 #endif
  27
  28
  29 /*
  30  * BSD-style getpeereid() for platforms that lack it.
  31  */
  32 int
  33 getpeereid(int sock, uid_t *uid, gid_t *gid)
  34 {
  35 #if defined(SO_PEERCRED)
  36         /* Linux: use getsockopt(SO_PEERCRED) */
  37         struct ucred peercred;
  38         socklen_t       so_len = sizeof(peercred);
  39
  40         if (getsockopt(sock, SOL_SOCKET, SO_PEERCRED, &peercred, &so_len) != 0 ||
  41                 so_len != sizeof(peercred))
  42                 return -1;
  43         *uid = peercred.uid;
  44         *gid = peercred.gid;
  45         return 0;
  46 #elif defined(LOCAL_PEERCRED)
  47         /* Debian with FreeBSD kernel: use getsockopt(LOCAL_PEERCRED) */
  48         struct xucred peercred;
  49         socklen_t       so_len = sizeof(peercred);
  50
  51         if (getsockopt(sock, 0, LOCAL_PEERCRED, &peercred, &so_len) != 0 ||
  52                 so_len != sizeof(peercred) ||
  53                 peercred.cr_version != XUCRED_VERSION)
  54                 return -1;
  55         *uid = peercred.cr_uid;
  56         *gid = peercred.cr_gid;
  57         return 0;
  58 #elif defined(HAVE_GETPEERUCRED)
  59         /* Solaris: use getpeerucred() */
  60         ucred_t    *ucred;
  61
  62         ucred = NULL;                           /* must be initialized to NULL */
  63         if (getpeerucred(sock, &ucred) == -1)
  64                 return -1;
  65
  66         *uid = ucred_geteuid(ucred);
  67         *gid = ucred_getegid(ucred);
  68         ucred_free(ucred);
  69
  70         if (*uid == (uid_t) (-1) || *gid == (gid_t) (-1))
  71                 return -1;
  72         return 0;
  73 #else
  74         /* No implementation available on this platform */
  75         errno = ENOSYS;
  76         return -1;
  77 #endif
  78 }