(PUP-7126) Replace matchpathcon with selabel_lookup

Since Selinux.matchpathcon is deprecated, selabel_lookup needs to be used
instead.

This commit replaces calls to matchpathcon with selabel_lookup by deprecating
get_selinux_default_context and replacing it with
get_selinux_default_context_with_handle. The new method requires a handle
since it calls selabel_lookup instead of matchpathcon and selabel_lookup
requires a handle.

Co-authored-by: William Bradford Clark <wclark@redhat.com>

lib/puppet/type/file/selcontext.rb

@@ -40,11 +40,13 @@ def retrieve
     end
 
     def retrieve_default_context(property)
+      return nil if Puppet::Util::Platform.windows?
+
       if @resource[:selinux_ignore_defaults] == :true
         return nil
       end
 
-      context = get_selinux_default_context(@resource[:path], @resource[:ensure])
+      context = get_selinux_default_context_with_handle(@resource[:path], @resource[:ensure], provider.class.selinux_handle)
       unless context
         return nil
       end
@@ -85,7 +87,7 @@ def sync
   end
 
   Puppet::Type.type(:file).newparam(:selinux_ignore_defaults) do
-    desc "If this is set then Puppet will not ask SELinux (via matchpathcon) to
+    desc "If this is set then Puppet will not ask SELinux (via selabel_lookup) to
       supply defaults for the SELinux attributes (seluser, selrole,
       seltype, and selrange). In general, you should leave this set at its
       default and only set it to true when you need Puppet to not try to fix
@@ -98,7 +100,7 @@ def sync
   Puppet::Type.type(:file).newproperty(:seluser, :parent => Puppet::SELFileContext) do
     desc "What the SELinux user component of the context of the file should be.
       Any valid SELinux user component is accepted.  For example `user_u`.
-      If not specified it defaults to the value returned by matchpathcon for
+      If not specified it defaults to the value returned by selabel_lookup for
       the file, if any exists.  Only valid on systems with SELinux support
       enabled."
 
@@ -109,7 +111,7 @@ def sync
   Puppet::Type.type(:file).newproperty(:selrole, :parent => Puppet::SELFileContext) do
     desc "What the SELinux role component of the context of the file should be.
       Any valid SELinux role component is accepted.  For example `role_r`.
-      If not specified it defaults to the value returned by matchpathcon for
+      If not specified it defaults to the value returned by selabel_lookup for
       the file, if any exists.  Only valid on systems with SELinux support
       enabled."
 
@@ -120,7 +122,7 @@ def sync
   Puppet::Type.type(:file).newproperty(:seltype, :parent => Puppet::SELFileContext) do
     desc "What the SELinux type component of the context of the file should be.
       Any valid SELinux type component is accepted.  For example `tmp_t`.
-      If not specified it defaults to the value returned by matchpathcon for
+      If not specified it defaults to the value returned by selabel_lookup for
       the file, if any exists.  Only valid on systems with SELinux support
       enabled."
 
@@ -132,7 +134,7 @@ def sync
     desc "What the SELinux range component of the context of the file should be.
       Any valid SELinux range component is accepted.  For example `s0` or
       `SystemHigh`.  If not specified it defaults to the value returned by
-      matchpathcon for the file, if any exists.  Only valid on systems with
+      selabel_lookup for the file, if any exists.  Only valid on systems with
       SELinux support enabled and that have support for MCS (Multi-Category
       Security)."
 

lib/puppet/util/selinux.rb

@@ -46,6 +46,7 @@ def get_selinux_current_context(file)
 
   # Retrieve and return the default context of the file.  If we don't have
   # SELinux support or if the SELinux call fails to file a default then return nil.
+  # @deprecated matchpathcon is a deprecated method, selabel_lookup is preferred
   def get_selinux_default_context(file, resource_ensure = nil)
     return nil unless selinux_support?
     # If the filesystem has no support for SELinux labels, return a default of nil
@@ -68,11 +69,36 @@ def get_selinux_default_context(file, resource_ensure = nil)
     end
 
     retval = Selinux.matchpathcon(file, mode)
-    if retval == -1
-      return nil
+    retval == -1 ? nil : retval[1]
+  end
+
+  def get_selinux_default_context_with_handle(file, handle, resource_ensure = nil)
+    return nil unless selinux_support?
+    # If the filesystem has no support for SELinux labels, return a default of nil
+    # instead of what selabel_lookup would return
+    return nil unless selinux_label_support?(file)
+    # If the file exists we should pass the mode to selabel_lookup for the most specific
+
+    # Handle is needed for selabel_lookup
+    raise ArgumentError, _("Cannot get default context with nil handle") unless handle
+
+    # If the file exists we should pass the mode to selabel_lookup for the most specific
+    # matching.  If not, we can pass a mode of 0.
+    begin
+      filestat = file_lstat(file)
+      mode = filestat.mode
+    rescue Errno::EACCES
+      mode = 0
+    rescue Errno::ENOENT
+      if resource_ensure
+        mode = get_create_mode(resource_ensure)
+      else
+        mode = 0
+      end
     end
 
-    retval[1]
+    retval = Selinux.selabel_lookup(handle, file, mode)
+    retval == -1 ? nil : retval[1]
   end
 
   # Take the full SELinux context returned from the tools and parse it

spec/unit/type/file/selinux_spec.rb

@@ -1,3 +1,4 @@
+#skip if Puppet::Util::Platform.windows?
 require 'spec_helper'
 
 [:seluser, :selrole, :seltype, :selrange].each do |param|
@@ -50,13 +51,15 @@
     end
 
     it "should handle no default gracefully" do
-      expect(@sel).to receive(:get_selinux_default_context).with(@path, :file).and_return(nil)
+      skip if Puppet::Util::Platform.windows?
+      expect(@sel).to receive(:get_selinux_default_context_with_handle).with(@path, :file, nil).and_return(nil)
       expect(@sel.default).to be_nil
     end
 
-    it "should be able to detect matchpathcon defaults" do
+    it "should be able to detect default context" do
+      skip if Puppet::Util::Platform.windows?
       allow(@sel).to receive(:debug)
-      expect(@sel).to receive(:get_selinux_default_context).with(@path, :file).and_return("user_u:role_r:type_t:s0")
+      expect(@sel).to receive(:get_selinux_default_context_with_handle).with(@path, :file, nil).and_return("user_u:role_r:type_t:s0")
       expectedresult = case param
         when :seluser; "user_u"
         when :selrole; "role_r"

spec/unit/util/selinux_spec.rb

@@ -241,6 +241,37 @@
     end
   end
 
+  describe "get_selinux_default_context_with_handle" do
+    it "should return a context if a default context exists" do
+      without_partial_double_verification do
+        expect(self).to receive(:selinux_support?).and_return(true)
+        fstat = double('File::Stat', :mode => 0)
+        expect(Puppet::FileSystem).to receive(:lstat).with('/foo').and_return(fstat)
+        expect(self).to receive(:find_fs).with("/foo").and_return("ext3")
+        hnd = double("SWIG::TYPE_p_selabel_handle")
+        expect(Selinux).to receive(:selabel_lookup).with(hnd, '/foo', 0).and_return([0, "user_u:role_r:type_t:s0"])
+        expect(get_selinux_default_context_with_handle("/foo", hnd)).to eq("user_u:role_r:type_t:s0")
+      end
+    end
+
+    it "should raise an ArgumentError when handle is nil" do
+      allow(self).to receive(:selinux_support?).and_return(true)
+      allow(self).to receive(:selinux_label_support?).and_return(true)
+      expect{get_selinux_default_context_with_handle("/foo", nil)}.to raise_error(ArgumentError, /Cannot get default context with nil handle/)
+    end
+
+    it "should return nil if there is no SELinux support" do
+      expect(self).to receive(:selinux_support?).and_return(false)
+      expect(get_selinux_default_context_with_handle("/foo", nil)).to be_nil
+    end
+
+    it "should return nil if selinux_label_support returns false" do
+      expect(self).to receive(:selinux_support?).and_return(true)
+      expect(self).to receive(:find_fs).with("/foo").and_return("nfs")
+      expect(get_selinux_default_context_with_handle("/foo", nil)).to be_nil
+    end
+  end
+
   describe "parse_selinux_context" do
     it "should return nil if no context is passed" do
       expect(parse_selinux_context(:seluser, nil)).to be_nil