Compare mount by value instead of reference

This has to be since the mounts are reloaded each time a mount is added. In case of two mounts mounting at the same time there will be a race condition for applying policy. Signed-off-by: NymanRobin <[email protected]>
google · May 2, 2024 · fcea5c9 · fcea5c9
1 parent 54745f1
commit fcea5c9
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Showing 4 changed files with 25 additions and 1 deletion.
diff --git a/actions/policy.go b/actions/policy.go
@@ -25,6 +25,7 @@ import (
 	"os"
 	"os/user"
 
+	"github.com/google/go-cmp/cmp"
 	"github.com/pkg/errors"
 	"google.golang.org/protobuf/proto"
 
@@ -525,7 +526,7 @@ func (policy *Policy) RemoveProtector(protectorDescriptor string) error {
 func (policy *Policy) Apply(path string) error {
 	if pathMount, err := filesystem.FindMount(path); err != nil {
 		return err
-	} else if pathMount != policy.Context.Mount {
+	} else if !cmp.Equal(pathMount, policy.Context.Mount) {
 		return &ErrDifferentFilesystem{policy.Context.Mount, pathMount}
 	}
 

diff --git a/filesystem/mountpoint_test.go b/filesystem/mountpoint_test.go
@@ -29,6 +29,8 @@ import (
 	"path/filepath"
 	"strings"
 	"testing"
+
+	"github.com/google/go-cmp/cmp"
 )
 
 func TestLoadMountInfo(t *testing.T) {
@@ -544,3 +546,21 @@ func BenchmarkLoadFirst(b *testing.B) {
 		}
 	}
 }
+
+// Test mount comparison by values instead of by reference,
+// as the map mountsByDevice gets recreated on each load.
+// This ensures that concurrent mounts work properly.
+func TestMountComparission(t *testing.T) {
+	var mountinfo = `
+15 0 259:3 / /home rw,relatime shared:1 - ext4 /dev/root rw,data=ordered
+`
+	beginLoadMountInfoTest()
+	loadMountInfoFromString(mountinfo)
+	fisrtMnt := mountForDevice("259:3")
+	loadMountInfoFromString(mountinfo)
+	defer endLoadMountInfoTest()
+	secondMnt := mountForDevice("259:3")
+	if !cmp.Equal(fisrtMnt, secondMnt) {
+		t.Fatal("Mount comparission does not work")
+	}
+}
diff --git a/go.mod b/go.mod
@@ -18,6 +18,7 @@ require (
 require (
 	github.com/BurntSushi/toml v1.3.2 // indirect
 	github.com/cpuguy83/go-md2man/v2 v2.0.2 // indirect
+	github.com/google/go-cmp v0.6.0 // indirect
 	github.com/russross/blackfriday/v2 v2.1.0 // indirect
 	golang.org/x/exp/typeparams v0.0.0-20221208152030-732eee02a75a // indirect
 	golang.org/x/mod v0.12.0 // indirect

diff --git a/go.sum b/go.sum
@@ -8,6 +8,8 @@ github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSs
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/google/go-cmp v0.5.5 h1:Khx7svrCpmxxtHBq5j2mp/xVjsi8hQMfNLvJFAlrGgU=
+github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=