add validation for registry/repo/image being passed

Signed-off-by: Harsh Thakur <[email protected]>

pkg/patch/patch.go

@@ -173,8 +173,15 @@ func patchedImageTarget(image, patchedTag string) (*string, error) {
 			patchedTag = fmt.Sprintf("%s-%s", tag, defaultPatchedTagSuffix)
 		}
 	}
-	// this implies user has passed a destination image name, not just a tag
-	if strings.Contains(patchedTag, "/") {
+
+	slashCount := strings.Count(patchedTag, "/")
+	if slashCount > 0 {
+		if slashCount < 2 {
+			err := fmt.Errorf("invalid tag %s, must be in the form <registry>/<image>:<tag>", patchedTag)
+			log.Error(err)
+			return nil, err
+		}
+		// this implies user has passed a destination image name, not just a tag
 		patchedImageName = patchedTag
 	} else {
 		patchedImageName = fmt.Sprintf("%s:%s", imageName.Name(), patchedTag)

pkg/patch/patch_test.go

@@ -74,10 +74,17 @@ func TestPatchedImageTarget(t *testing.T) {
 			wantErr:    false,
 		},
 		{
-			name:       "tag passed and contains a slash(indicating registry)",
+			name:       "tag passed but without registry or repo",
 			image:      "docker.io/library/nginx:1.21.3",
 			patchedTag: "my.registry/nginx:1.21.3-patched",
-			want:       "my.registry/nginx:1.21.3-patched",
+			want:       "",
+			wantErr:    true,
+		},
+		{
+			name:       "tag passed containg registry, repo and image",
+			image:      "docker.io/library/nginx:1.21.3",
+			patchedTag: "my.registry.io/myrepo/nginx:1.21.3-patched",
+			want:       "my.registry.io/myrepo/nginx:1.21.3-patched",
 			wantErr:    false,
 		},
 	}
@@ -89,8 +96,10 @@ func TestPatchedImageTarget(t *testing.T) {
 				t.Errorf("patchedImageTarget() error = %v, wantErr %v", err, tt.wantErr)
 				return
 			}
-			if *got != tt.want {
-				t.Errorf("patchedImageTarget() = %v, want %v", *got, tt.want)
+			if got != nil {
+				if *got != tt.want {
+					t.Errorf("patchedImageTarget() = %v, want %v", *got, tt.want)
+				}
 			}
 		})
 	}