(PUP-7126) Replace deprecated Selinux.matchpathcon functions

This commit:
- Deprecates get_selinux_default_context which calls the deprecated
  Selinux.matchpathcon and replaces it with
  get_selinux_default_context_with_handle which calls Selinux.selabel_lookup
  instead. The new method requires a handle since selabel_lookup requires a
  handle
- Adds a getter method for the class variable, selinux_handle, in the POSIX
  file provider which is used to get the handle for
  get_selinux_default_context_with_handle. With this getter method,
  selinux_handle will only initialized once with Selinux.selabel_lookup.
- Updates post_resource_eval in the POSIX file provider to call
  Selinux.selabel_close instead of the deprecated Selinux.matchpathcon_fini
  when terminating selinux_handle. After, selinux_handle is set to nil.

Co-authored-by: William Bradford Clark <[email protected]>

Author: AriaXLi

lib/puppet/provider/file/posix.rb

@@ -12,8 +12,22 @@
   require 'etc'
   require_relative '../../../puppet/util/selinux'
 
-  def self.post_resource_eval
-    Selinux.matchpathcon_fini if Puppet::Util::SELinux.selinux_support?
+  class << self
+    def selinux_handle
+      return nil unless Puppet::Util::SELinux.selinux_support?
+
+      # selabel_open takes 3 args: backend, options, and nopt. The backend param
+      # is a constant, SELABEL_CTX_FILE, which happens to be 0. Since options is
+      # nil, nopt can be 0 since nopt represents the # of options specified.
+      @selinux_handle ||= Selinux.selabel_open(Selinux::SELABEL_CTX_FILE, nil, 0)
+    end
+
+    def post_resource_eval
+      if @selinux_handle
+        Selinux.selabel_close(@selinux_handle)
+        @selinux_handle = nil
+      end
+    end
   end
 
   def uid2name(id)

lib/puppet/type/file/selcontext.rb

@@ -40,11 +40,12 @@ 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], provider.class.selinux_handle)
       unless context
         return nil
       end
@@ -85,7 +86,7 @@ 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 +99,7 @@ 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 +110,7 @@ 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 +121,7 @@ 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 +133,7 @@ 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 +69,20 @@ def get_selinux_default_context(file, resource_ensure = nil)
     end
 
     retval = Selinux.matchpathcon(file, mode)
-    if retval == -1
-      return nil
-    end
+    retval == -1 ? nil : retval[1]
+  end
 
-    retval[1]
+  def get_selinux_default_context_with_handle(file, handle)
+    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)
+
+    # Handle is needed for selabel_lookup
+    raise ArgumentError, _("Cannot get default context with nil handle") unless handle
+
+    retval = Selinux.selabel_lookup(handle, file, 0)
+    retval == -1 ? nil : retval[1]
   end
 
   # Take the full SELinux context returned from the tools and parse it

spec/unit/transaction_spec.rb

@@ -758,15 +758,15 @@ def post_resource_eval
       transaction.evaluate
     end
 
-    it "should call Selinux.matchpathcon_fini in case Selinux is enabled ", :if => Puppet.features.posix? do
-      selinux = double('selinux', is_selinux_enabled: true, matchpathcon_fini: nil)
+    it "should call Selinux.selabel_close in case Selinux is enabled", :if => Puppet.features.posix? do
+      handle = double('selinux_handle')
+      selinux = class_double('selinux', is_selinux_enabled: 1, selabel_close: nil, selabel_open: handle, selabel_lookup: -1)
       stub_const('Selinux', selinux)
-
+      stub_const('Selinux::SELABEL_CTX_FILE', 0)
       resource = Puppet::Type.type(:file).new(:path => make_absolute("/tmp/foo"))
       transaction = transaction_with_resource(resource)
 
-      expect(Selinux).to receive(:matchpathcon_fini)
-      expect(Puppet::Util::SELinux).to receive(:selinux_support?).and_return(true)
+      expect(Selinux).to receive(:selabel_close).with(handle)
 
       transaction.evaluate
     end

spec/unit/type/file/selinux_spec.rb

@@ -50,13 +50,16 @@
     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, 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 on platforms other than Windows", unless: Puppet::Util::Platform.windows? do
       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")
+      hnd = double("SWIG::TYPE_p_selabel_handle")
+      allow(@sel.provider.class).to receive(:selinux_handle).and_return(hnd)
+      expect(@sel).to receive(:get_selinux_default_context_with_handle).with(@path, hnd).and_return("user_u:role_r:type_t:s0")
       expectedresult = case param
         when :seluser; "user_u"
         when :selrole; "role_r"
@@ -66,6 +69,11 @@
       expect(@sel.default).to eq(expectedresult)
     end
 
+    it "returns nil default context on Windows", if: Puppet::Util::Platform.windows? do
+      expect(@sel).to receive(:retrieve_default_context)
+      expect(@sel.default).to be_nil
+    end
+
     it "should return nil for defaults if selinux_ignore_defaults is true" do
       @resource[:selinux_ignore_defaults] = :true
       expect(@sel.default).to be_nil

spec/unit/util/selinux_spec.rb

@@ -241,6 +241,35 @@
     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)
+        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