Index: openacs-4/packages/xowiki/xowiki.info
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xowiki/xowiki.info,v
diff -u -r1.180.2.85 -r1.180.2.86
--- openacs-4/packages/xowiki/xowiki.info	8 Feb 2022 10:11:49 -0000	1.180.2.85
+++ openacs-4/packages/xowiki/xowiki.info	18 Feb 2022 18:32:28 -0000	1.180.2.86
@@ -10,7 +10,7 @@
     <inherit-templates-p>t</inherit-templates-p>
     <auto-mount>xowiki</auto-mount>
 
-    <version name="5.10.1d16" url="http://openacs.org/repository/download/apm/xowiki-5.10.1d16.apm">
+    <version name="5.10.1d17" url="http://openacs.org/repository/download/apm/xowiki-5.10.1d17.apm">
 	<owner url="mailto:neumann@wu-wien.ac.at">Gustaf Neumann</owner>
 	<summary>A xotcl-based enterprise wiki system with multiple object types</summary>
 	<release-date>2021-09-15</release-date>
@@ -55,11 +55,11 @@
 	<license>BSD-Style</license>
 	<maturity>2</maturity>
 
-	<provides url="xowiki" version="5.10.1d16"/>
+	<provides url="xowiki" version="5.10.1d17"/>
 	<requires url="xotcl-core" version="5.10.1d1"/>
 	<requires url="acs-datetime" version="5.9.1"/>
 	<requires url="acs-kernel" version="5.10.0"/>
-	<requires url="acs-tcl" version="5.10.0"/>
+	<requires url="acs-tcl" version="5.10.1d9"/>
 	<requires url="acs-templating" version="5.10.1d0"/>
 	<requires url="acs-subsite" version="5.10.0"/>
 	<requires url="acs-lang" version="5.10.0"/>
Index: openacs-4/packages/xowiki/tcl/import-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xowiki/tcl/import-procs.tcl,v
diff -u -r1.42.2.8 -r1.42.2.9
--- openacs-4/packages/xowiki/tcl/import-procs.tcl	17 Feb 2021 08:27:59 -0000	1.42.2.8
+++ openacs-4/packages/xowiki/tcl/import-procs.tcl	18 Feb 2022 18:32:28 -0000	1.42.2.9
@@ -398,26 +398,35 @@
   }
   ArchiveFile instproc unpack {} {
     set success 0
-    #:log "::xowiki::guesstype '${:name}' => [::xowiki::guesstype ${:name}]"
     switch [::xowiki::guesstype ${:name}] {
       application/zip -
       application/x-zip -
       application/x-zip-compressed {
-        ::util::unzip -source ${:file} -destination ${:tmpdir}
-        :import -dir ${:tmpdir} -parent_id ${:parent_id}
-        set success 1
+        set success [util::file_content_check -type zip -file ${:file}]
+        if {!$success} {
+          util_user_message -message "The uploaded file is apparently not a zip file."
+        } else {
+          ::util::unzip -source ${:file} -destination ${:tmpdir}
+          :import -dir ${:tmpdir} -parent_id ${:parent_id}
+        }
       }
       application/x-compressed {
         if {[string match "*tar.gz" ${:name}]} {
-          set cmd [::util::which tar]
-          exec $cmd -xzf ${:file} -C ${:tmpdir}
-          :import -dir ${:tmpdir} -parent_id ${:parent_id}
-          set success 1
+          set success [util::file_content_check -type gzip -file ${:file}]
+          if {!$success} {
+            util_user_message -message "The uploaded file is apparently not a gzip file."
+          } else {
+            set cmd [::util::which tar]
+            exec $cmd -xzf ${:file} -C ${:tmpdir}
+            :import -dir ${:tmpdir} -parent_id ${:parent_id}
+          }
         } else {
-          :msg "unknown compressed file type ${:name}"
+          util_user_message -message "Unknown compressed file type ${:name}."
         }
       }
-      default {:msg "type [::xowiki::guesstype ${:name}] of ${:name} unknown"}
+      default {
+        util_user_message -message "Type '[::xowiki::guesstype ${:name}]' is not an supported archive format."
+      }
     }
     #:msg success=$success
     return $success
Index: openacs-4/packages/xowiki/www/admin/import.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xowiki/www/admin/import.tcl,v
diff -u -r1.28.2.6 -r1.28.2.7
--- openacs-4/packages/xowiki/www/admin/import.tcl	7 Oct 2020 10:09:42 -0000	1.28.2.6
+++ openacs-4/packages/xowiki/www/admin/import.tcl	18 Feb 2022 18:32:28 -0000	1.28.2.7
@@ -38,9 +38,19 @@
       }
 
       set upload_tmpfile [template::util::file::get_property tmp_filename $upload_file]
-      set f [open $upload_tmpfile];
-      # if we do not set translation binary,
+
+      set file_looks_ok [util::file_content_check -type export -file ${upload_tmpfile}]
+      if {!$file_looks_ok} {
+        template::form::set_error upload_form upload_file \
+            "The provided file is not in the export file format"
+        break
+      }
+      
+      set f [open $upload_tmpfile]
+      #
+      # If we do not set translation binary,
       # backslashes at the end of the lines might be lost
+      #
       fconfigure $f -translation binary -encoding utf-8
       set content [read $f]; close $f