Add support for --enable-sasl and --disable-sasl to make it possible

to enable/disable support for LDAP with SASL authentication.  Sudo
compiles in support for SASL authentiation by default if the
ldap_sasl_interactive_bind_s() function is detected.
Bug #788

INSTALL

@@ -312,6 +312,12 @@ Optional features:
 	this file instead of /etc/ldap.secret to read the secret password
 	when rootbinddn is specified in the ldap config file.
 
+  --disable-sasl
+        Disable SASL authentication for LDAP.  By default, sudo
+        will compile in support for SASL authentication if the
+        ldap_sasl_interactive_bind_s() function is present in the
+        LDAP libraries.
+
   --with-logincap
 	This adds support for login classes specified in /etc/login.conf.
 	It is enabled by default on BSD/OS, Darwin, FreeBSD, OpenBSD and

configure

@@ -962,6 +962,7 @@ enable_shared_libutil
 enable_tmpfiles_d
 enable_devsearch
 with_selinux
+enable_sasl
 enable_gss_krb5_ccache_name
 enable_shared
 enable_static
@@ -1645,6 +1646,7 @@ Optional Features:
   --enable-tmpfiles.d=DIR Set the path to the systemd tmpfiles.d directory.
   --enable-devsearch=PATH The colon-delimited path to search for device nodes
                           when determing the tty name.
+  --enable-sasl           Enable/disable LDAP SASL support
   --enable-gss-krb5-ccache-name
                           Use GSS-API to set the Kerberos V cred cache name
   --enable-shared[=PKGS]  build shared libraries [default=yes]
@@ -6751,6 +6753,18 @@ else
 fi
 
 
+# Check whether --enable-sasl was given.
+if test "${enable_sasl+set}" = set; then :
+  enableval=$enable_sasl;  case "$enableval" in
+    yes|no) ;;
+    *)	    { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: Ignoring unknown argument to --enable-sasl: $enableval" >&5
+$as_echo "$as_me: WARNING: Ignoring unknown argument to --enable-sasl: $enableval" >&2;}
+	    ;;
+  esac
+
+fi
+
+
 # Check whether --enable-gss_krb5_ccache_name was given.
 if test "${enable_gss_krb5_ccache_name+set}" = set; then :
   enableval=$enable_gss_krb5_ccache_name; check_gss_krb5_ccache_name=$enableval
@@ -22552,7 +22566,7 @@ if eval test \"x\$"$as_ac_Lib"\" = x"yes"; then :
 fi
 
     #
-    # Some PAM implementations (MacOS X for example) put the PAM headers
+    # Some PAM implementations (macOS for example) put the PAM headers
     # in /usr/include/pam instead of /usr/include/security...
     #
     found_pam_hdrs=no
@@ -24695,7 +24709,9 @@ fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
 
-    for ac_header in sasl/sasl.h sasl.h
+    if test ${enable_sasl-'yes'} = "yes"; then
+	found_sasl_h=no
+	for ac_header in sasl/sasl.h sasl.h
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
@@ -24704,7 +24720,8 @@ if eval test \"x\$"$as_ac_Header"\" = x"yes"; then :
 #define `$as_echo "HAVE_$ac_header" | $as_tr_cpp` 1
 _ACEOF
 
-	for ac_func in ldap_sasl_interactive_bind_s
+	    found_sasl_h=yes
+	    for ac_func in ldap_sasl_interactive_bind_s
 do :
   ac_fn_c_check_func "$LINENO" "ldap_sasl_interactive_bind_s" "ac_cv_func_ldap_sasl_interactive_bind_s"
 if test "x$ac_cv_func_ldap_sasl_interactive_bind_s" = xyes; then :
@@ -24715,12 +24732,21 @@ _ACEOF
 fi
 done
 
-	break
+	    break
 
 fi
 
 done
 
+	if test X${enable_sasl} = X"yes"; then
+	    if test X"$found_sasl_h" != X"yes"; then
+		as_fn_error $? "\"--enable-sasl specified but unable to locate SASL development headers.\"" "$LINENO" 5
+	    fi
+	    if test X"$ac_cv_func_ldap_sasl_interactive_bind_s" != X"yes"; then :
+		as_fn_error $? "\"--enable-sasl specified but SASL support is missing in your LDAP library\"" "$LINENO" 5
+	    fi
+	fi
+    fi
     for ac_header in ldap_ssl.h mps/ldap_ssl.h
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`

configure.ac

@@ -1562,6 +1562,15 @@ AC_ARG_WITH(selinux, [AS_HELP_STRING([--with-selinux], [enable SELinux support])
 		;;
 esac], [with_selinux=no])
 
+AC_ARG_ENABLE(sasl,
+[AS_HELP_STRING([--enable-sasl], [Enable/disable LDAP SASL support])],
+[ case "$enableval" in
+    yes|no) ;;
+    *)	    AC_MSG_WARN([Ignoring unknown argument to --enable-sasl: $enableval])
+	    ;;
+  esac
+])
+
 dnl
 dnl gss_krb5_ccache_name() may not work on Heimdal so we don't use it by default
 dnl
@@ -3745,10 +3754,22 @@ if test ${with_ldap-'no'} != "no"; then
     AC_MSG_RESULT([yes])
     AC_DEFINE(HAVE_LBER_H)])
 
-    AC_CHECK_HEADERS([sasl/sasl.h] [sasl.h], [
+    if test ${enable_sasl-'yes'} = "yes"; then
-	AC_CHECK_FUNCS([ldap_sasl_interactive_bind_s])
+	found_sasl_h=no
-	break
+	AC_CHECK_HEADERS([sasl/sasl.h] [sasl.h], [
-    ])
+	    found_sasl_h=yes
+	    AC_CHECK_FUNCS([ldap_sasl_interactive_bind_s])
+	    break
+	])
+	if test X${enable_sasl} = X"yes"; then
+	    if test X"$found_sasl_h" != X"yes"; then
+		AC_MSG_ERROR(["--enable-sasl specified but unable to locate SASL development headers."])
+	    fi
+	    if test X"$ac_cv_func_ldap_sasl_interactive_bind_s" != X"yes"; then :
+		AC_MSG_ERROR(["--enable-sasl specified but SASL support is missing in your LDAP library"])
+	    fi
+	fi
+    fi
     AC_CHECK_HEADERS([ldap_ssl.h] [mps/ldap_ssl.h], [break], [], [#include <ldap.h>])
     AC_CHECK_FUNCS([ldap_initialize ldap_start_tls_s ldapssl_init ldapssl_set_strength ldap_unbind_ext_s ldap_str2dn ldap_create ldap_sasl_bind_s ldap_ssl_init ldap_ssl_client_init ldap_start_tls_s_np])
     AC_CHECK_FUNCS([ldap_search_ext_s ldap_search_st], [break])