Revert "Check effective credentials of socket peers"

This reverts commit 8412c867a501e3a68e55fef6215e86d3ac9f617b.

Just checking the credentials of the peer turns out to be insufficient.
See https://github.com/fish-shell/fish-shell/issues/1436.

7 files changed, 5 insertions, 137 deletions

diff --git a/configure.ac b/configure.ac
index bdfa5f0e..ea7c592f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -557,7 +557,7 @@ LIBS=$LIBS_COMMON
 # Check presense of various header files
 #
 
-AC_CHECK_HEADERS([getopt.h termios.h sys/resource.h term.h ncurses/term.h ncurses.h curses.h stropts.h siginfo.h sys/select.h sys/ioctl.h execinfo.h spawn.h sys/sysctl.h sys/un.h sys/ucred.h ucred.h ])
+AC_CHECK_HEADERS([getopt.h termios.h sys/resource.h term.h ncurses/term.h ncurses.h curses.h stropts.h siginfo.h sys/select.h sys/ioctl.h execinfo.h spawn.h sys/sysctl.h])
 
 if test x$local_gettext != xno; then
   AC_CHECK_HEADERS([libintl.h])
@@ -698,7 +698,7 @@ fi
 AC_CHECK_FUNCS( wcsdup wcsndup wcslen wcscasecmp wcsncasecmp fwprintf )
 AC_CHECK_FUNCS( futimes wcwidth wcswidth wcstok fputwc fgetwc )
 AC_CHECK_FUNCS( wcstol wcslcat wcslcpy lrand48_r killpg )
-AC_CHECK_FUNCS( backtrace backtrace_symbols sysconf getifaddrs getpeerucred getpeereid )
+AC_CHECK_FUNCS( backtrace backtrace_symbols sysconf getifaddrs )
 
 if test x$local_gettext != xno; then
   AC_CHECK_FUNCS( gettext dcgettext )
diff --git a/doc_src/license.hdr b/doc_src/license.hdr
index f292722b..64bab10f 100644
--- a/doc_src/license.hdr
+++ b/doc_src/license.hdr
@@ -1400,34 +1400,6 @@ POSSIBILITY OF SUCH DAMAGES.
 
 <P>
 
-<hr>
-
-<h2>License for getpeereid</h2>
-
-\c fish contains code imported from the PostgreSQL project under
-license, namely the getpeereid fallback function. This code is copyrighted
-by:
-
-Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
-
-Portions Copyright (c) 1994, The Regents of the University of California
-
-Permission to use, copy, modify, and distribute this software and its
-documentation for any purpose, without fee, and without a written agreement
-is hereby granted, provided that the above copyright notice and this
-paragraph and the following two paragraphs appear in all copies.
-
-IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
-DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
-LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
-DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE
-POSSIBILITY OF SUCH DAMAGE.
-
-THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
-INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
-AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
-ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATIONS TO
-PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+*/
 
 \htmlonly </div> \endhtmlonly
-*/
diff --git a/env_universal.cpp b/env_universal.cpp
index 987f88b0..c7d060ad 100644
--- a/env_universal.cpp
+++ b/env_universal.cpp
@@ -88,8 +88,6 @@ static int try_get_socket_once(void)
 
     wdir = path;
     wuname = user;
-    uid_t seuid;
-    gid_t segid;
 
     if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
     {
@@ -137,13 +135,6 @@ static int try_get_socket_once(void)
         return -1;
     }
 
-    if ((getpeereid(s, &seuid, &segid) != 0) || seuid != geteuid())
-    {
-        debug(1, L"Wrong credentials for socket %s at fd %d", name.c_str(), s);
-        close(s);
-        return -1;
-    }
-
     if ((make_fd_nonblocking(s) != 0) || (fcntl(s, F_SETFD, FD_CLOEXEC) != 0))
     {
         wperror(L"fcntl");
diff --git a/fallback.cpp b/fallback.cpp
index 34db3973..5e4b3e1b 100644
--- a/fallback.cpp
+++ b/fallback.cpp
@@ -15,9 +15,8 @@
 #include <stdio.h>
 #include <unistd.h>
 #include <sys/types.h>
-#include <sys/socket.h>
 #include <sys/stat.h>
-#include <sys/param.h>
+#include <unistd.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <wchar.h>
@@ -1522,80 +1521,3 @@ static int mk_wcswidth(const wchar_t *pwcs, size_t n)
 }
 
 #endif // HAVE_BROKEN_WCWIDTH
-
-#ifndef HAVE_GETPEEREID
-
-/*-------------------------------------------------------------------------
- *
- * getpeereid.c
- *		get peer userid for UNIX-domain socket connection
- *
- * Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
- *
- *
- * IDENTIFICATION
- *	  src/port/getpeereid.c
- *
- *-------------------------------------------------------------------------
- */
-
-#ifdef HAVE_SYS_UN_H
-#include <sys/un.h>
-#endif
-#ifdef HAVE_UCRED_H
-#include <ucred.h>
-#endif
-#ifdef HAVE_SYS_UCRED_H
-#include <sys/ucred.h>
-#endif
-
-/*
- * BSD-style getpeereid() for platforms that lack it.
- */
-int getpeereid(int sock, uid_t *uid, gid_t *gid)
-{
-#if defined(SO_PEERCRED)
-	/* Linux: use getsockopt(SO_PEERCRED) */
-	struct ucred peercred;
-	socklen_t so_len = sizeof(peercred);
-
-	if (getsockopt(sock, SOL_SOCKET, SO_PEERCRED, &peercred, &so_len) != 0 ||
-		so_len != sizeof(peercred))
-		return -1;
-	*uid = peercred.uid;
-	*gid = peercred.gid;
-	return 0;
-#elif defined(LOCAL_PEERCRED)
-	/* Debian with FreeBSD kernel: use getsockopt(LOCAL_PEERCRED) */
-	struct xucred peercred;
-	socklen_t * so_len = sizeof(peercred);
-
-	if (getsockopt(sock, 0, LOCAL_PEERCRED, &peercred, &so_len) != 0 ||
-		so_len != sizeof(peercred) ||
-		peercred.cr_version != XUCRED_VERSION)
-		return -1;
-	*uid = peercred.cr_uid;
-	*gid = peercred.cr_gid;
-	return 0;
-#elif defined(HAVE_GETPEERUCRED)
-	/* Solaris: use getpeerucred() */
-	ucred_t    *ucred;
-
-	ucred = NULL;				/* must be initialized to NULL */
-	if (getpeerucred(sock, &ucred) == -1)
-		return -1;
-
-	*uid = ucred_geteuid(ucred);
-	*gid = ucred_getegid(ucred);
-	ucred_free(ucred);
-
-	if (*uid == (uid_t) (-1) || *gid == (gid_t) (-1))
-		return -1;
-	return 0;
-#else
-	/* No implementation available on this platform */
-	errno = ENOSYS;
-	return -1;
-#endif
-}
-#endif // HAVE_GETPEEREID
diff --git a/fallback.h b/fallback.h
index 6898ea57..eba91be6 100644
--- a/fallback.h
+++ b/fallback.h
@@ -482,7 +482,3 @@ double nan(char *tagp);
 
 
 #endif
-
-#ifndef HAVE_GETPEEREID
-int getpeereid(int sock, uid_t *uid, gid_t *gid);
-#endif
diff --git a/fishd.cpp b/fishd.cpp
index 1e095244..edb79c22 100644
--- a/fishd.cpp
+++ b/fishd.cpp
@@ -880,8 +880,6 @@ int main(int argc, char ** argv)
     int child_socket;
     struct sockaddr_un remote;
     socklen_t t;
-    uid_t sock_euid;
-    gid_t sock_egid;
     int max_fd;
     int update_count=0;
 
@@ -1002,12 +1000,7 @@ int main(int argc, char ** argv)
             {
                 debug(4, L"Connected with new child on fd %d", child_socket);
 
-                if (((getpeereid(child_socket, &sock_euid, &sock_egid) != 0) || sock_euid != geteuid()))
-                {
-                    debug(1, L"Wrong credentials for child on fd %d", child_socket);
-                    close(child_socket);
-                }
-                else if (make_fd_nonblocking(child_socket) != 0)
+                if (make_fd_nonblocking(child_socket) != 0)
                 {
                     wperror(L"fcntl");
                     close(child_socket);
diff --git a/osx/config.h b/osx/config.h
index bc058ae6..4968a78b 100644
--- a/osx/config.h
+++ b/osx/config.h
@@ -40,12 +40,6 @@
 /* Define to 1 if you have the <getopt.h> header file. */
 #define HAVE_GETOPT_H 1
 
-/* Define to 1 if you have the `getpeereid' function. */
-#define HAVE_GETPEEREID 1
-
-/* Define to 1 if you have the `getpeerucred' function. */
-/* #undef HAVE_GETPEERUCRED */
-
 /* Define to 1 if you have the `gettext' function. */
 /* #undef HAVE_GETTEXT */