fix(storage): deleting manifests with identical digests (#951)

Suppose we push two identical manifests (sharing same digest) but with
different tags, then deleting by digest should throw an error otherwise
we end up deleting all image tags (with gc) or dangling references
(without gc)

This behaviour is controlled via Authorization, added a new policy
action named detectManifestsCollision which enables this behaviour

Signed-off-by: Ramkumar Chinchani <rchincha@cisco.com>
Signed-off-by: Petu Eusebiu <peusebiu@cisco.com>

Co-authored-by: Ramkumar Chinchani <rchincha@cisco.com>

test/blackbox/anonymous_policy.bats

@@ -53,7 +53,6 @@ function setup_file() {
     }
 }
 EOF
-    git -C ${BATS_FILE_TMPDIR} clone https://github.com/project-zot/helm-charts.git
     setup_zot_file_level ${zot_config_file}
     wait_zot_reachable "http://127.0.0.1:8080/v2/_catalog"   
 }
@@ -66,7 +65,6 @@ function teardown_file() {
     rm -rf ${oci_data_dir}
 }
 
-
 @test "push image user policy" {
     run skopeo --insecure-policy copy --dest-creds test:test --dest-tls-verify=false \
         oci:${TEST_DATA_DIR}/golang:1.18 \
@@ -74,7 +72,6 @@ function teardown_file() {
     [ "$status" -eq 0 ]
 }
 
-
 @test "pull image anonymous policy" {
     local oci_data_dir=${BATS_FILE_TMPDIR}/oci
     run skopeo --insecure-policy copy --src-tls-verify=false \

test/blackbox/detect_manifest_collision.bats

@@ -0,0 +1,109 @@
+load helpers_pushpull
+
+function setup_file() {
+    # Verify prerequisites are available
+    if ! verify_prerequisites; then
+        exit 1
+    fi
+
+    # Download test data to folder common for the entire suite, not just this file
+    skopeo --insecure-policy copy --format=oci docker://ghcr.io/project-zot/golang:1.19 oci:${TEST_DATA_DIR}/golang:1.19
+    # Setup zot server
+    local zot_root_dir=${BATS_FILE_TMPDIR}/zot
+    local zot_config_file=${BATS_FILE_TMPDIR}/zot_config.json
+    local oci_data_dir=${BATS_FILE_TMPDIR}/oci
+    local htpasswordFile=${BATS_FILE_TMPDIR}/htpasswd
+    mkdir -p ${zot_root_dir}
+    mkdir -p ${oci_data_dir}
+    echo 'test:$2a$10$EIIoeCnvsIDAJeDL4T1sEOnL2fWOvsq7ACZbs3RT40BBBXg.Ih7V.' >> ${htpasswordFile}
+    cat > ${zot_config_file}<<EOF
+{
+    "distSpecVersion": "1.0.1",
+    "storage": {
+        "rootDirectory": "${zot_root_dir}"
+    },
+    "http": {
+        "address": "127.0.0.1",
+        "port": "8080",
+        "auth": {
+            "htpasswd": {
+                "path": "${htpasswordFile}"
+            }
+        },
+        "accessControl": {
+            "**": {
+                "anonymousPolicy": [ 
+                    "read",
+                    "create",
+                    "delete",
+                    "detectManifestCollision"
+                ],
+                "policies": [
+                    {
+                        "users": [
+                            "test"
+                        ],
+                        "actions": [
+                            "read",
+                            "create",
+                            "delete"
+                        ]
+                    }
+                ]
+            }
+        }
+    },
+    "log": {
+        "level": "debug"
+    }
+}
+EOF
+    setup_zot_file_level ${zot_config_file}
+    wait_zot_reachable "http://127.0.0.1:8080/v2/_catalog"   
+}
+
+function teardown_file() {
+    local zot_root_dir=${BATS_FILE_TMPDIR}/zot
+    local oci_data_dir=${BATS_FILE_TMPDIR}/oci
+    teardown_zot_file_level
+    rm -rf ${zot_root_dir}
+    rm -rf ${oci_data_dir}
+}
+
+@test "push 2 images with same manifest with user policy" {
+    run skopeo --insecure-policy copy --dest-creds test:test --dest-tls-verify=false \
+        oci:${TEST_DATA_DIR}/golang:1.19 \
+        docker://127.0.0.1:8080/golang:1.19
+    [ "$status" -eq 0 ]
+
+    run skopeo --insecure-policy copy --dest-creds test:test --dest-tls-verify=false \
+        oci:${TEST_DATA_DIR}/golang:1.19 \
+        docker://127.0.0.1:8080/golang:latest
+    [ "$status" -eq 0 ]
+}
+
+@test "skopeo delete image with anonymous policy should fail" {
+    # skopeo deletes by digest, so it should fail with detectManifestCollision policy
+    run skopeo --insecure-policy delete --tls-verify=false \
+        docker://127.0.0.1:8080/golang:1.19
+    [ "$status" -eq 1 ]
+    # conflict status code
+    [[ "$output" == *"409"* ]]
+}
+
+@test "regctl delete image with anonymous policy should fail" {
+    run regctl registry set localhost:8080 --tls disabled
+    [ "$status" -eq 0 ]
+
+    run regctl image delete localhost:8080/golang:1.19 --force-tag-dereference
+    [ "$status" -eq 1 ]
+    # conflict status code
+    [[ "$output" == *"409"* ]]
+}
+
+@test "delete image with user policy should work" {
+    # should work without detectManifestCollision policy
+    run skopeo --insecure-policy delete --creds test:test --tls-verify=false \
+        docker://127.0.0.1:8080/golang:1.19
+    [ "$status" -eq 0 ]
+}