diff --git a/extensions/permissions/PermissionManager.cpp b/extensions/permissions/PermissionManager.cpp
index 85b6647ef401..a443a6b2a1fe 100644
--- a/extensions/permissions/PermissionManager.cpp
+++ b/extensions/permissions/PermissionManager.cpp
@@ -2471,6 +2471,20 @@ NS_IMETHODIMP PermissionManager::GetAllWithTypePrefix(
       aResult);
 }
 
+NS_IMETHODIMP PermissionManager::GetAllByTypes(
+    const nsTArray<nsCString>& aTypes,
+    nsTArray<RefPtr<nsIPermission>>& aResult) {
+  if (aTypes.IsEmpty()) {
+    return NS_OK;
+  }
+
+  return GetPermissionEntries(
+      [&](const PermissionEntry& aPermEntry) {
+        return aTypes.Contains(mTypeArray[aPermEntry.mType]);
+      },
+      aResult);
+}
+
 nsresult PermissionManager::GetAllForPrincipalHelper(
     nsIPrincipal* aPrincipal, bool aSiteScopePermissions,
     nsTArray<RefPtr<nsIPermission>>& aResult) {
diff --git a/extensions/permissions/test/unit/test_permmanager_getAllByTypes.js b/extensions/permissions/test/unit/test_permmanager_getAllByTypes.js
new file mode 100644
index 000000000000..8353ed2282f9
--- /dev/null
+++ b/extensions/permissions/test/unit/test_permmanager_getAllByTypes.js
@@ -0,0 +1,121 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function check_enumerator(permissionTypes, expectedPermissions) {
+  const permissions = Services.perms.getAllByTypes(permissionTypes);
+
+  Assert.equal(
+    permissions.length,
+    expectedPermissions.length,
+    `getAllByTypes returned the expected number of permissions for ${JSON.stringify(
+      permissionTypes
+    )}`
+  );
+
+  permissions.forEach((perm, i) => {
+    info(`Checking permission #${i}`);
+    const [
+      expectedPrincipal,
+      expectedType,
+      expectedCapability,
+    ] = expectedPermissions[i];
+
+    Assert.ok(perm != null);
+    Assert.ok(perm.principal.equals(expectedPrincipal));
+    Assert.equal(perm.type, expectedType);
+    Assert.equal(perm.capability, expectedCapability);
+    Assert.equal(perm.expireType, Services.perms.EXPIRE_NEVER);
+  });
+}
+
+function run_test() {
+  let pm = Services.perms;
+
+  let principal = Services.scriptSecurityManager.createContentPrincipalFromOrigin(
+    "http://example.com"
+  );
+  let subPrincipal = Services.scriptSecurityManager.createContentPrincipalFromOrigin(
+    "http://sub.example.com"
+  );
+
+  const PERM_TYPE_1 = "test/getallbytypes_1";
+  const PERM_TYPE_2 = "test/getallbytypes_2";
+
+  info("check default state");
+  check_enumerator([], []);
+  check_enumerator([PERM_TYPE_1], []);
+  check_enumerator([PERM_TYPE_2], []);
+  check_enumerator([PERM_TYPE_1, PERM_TYPE_2], []);
+
+  info("check that expected permissions are retrieved");
+  pm.addFromPrincipal(principal, PERM_TYPE_1, pm.ALLOW_ACTION);
+  pm.addFromPrincipal(
+    subPrincipal,
+    "other-test/getallbytypes_1",
+    pm.PROMPT_ACTION
+  );
+  check_enumerator([PERM_TYPE_1], [[principal, PERM_TYPE_1, pm.ALLOW_ACTION]]);
+  check_enumerator(
+    [PERM_TYPE_1, PERM_TYPE_2],
+    [[principal, PERM_TYPE_1, pm.ALLOW_ACTION]]
+  );
+  check_enumerator([], []);
+  check_enumerator([PERM_TYPE_2], []);
+
+  pm.addFromPrincipal(subPrincipal, PERM_TYPE_1, pm.PROMPT_ACTION);
+  check_enumerator(
+    [PERM_TYPE_1],
+    [
+      [subPrincipal, PERM_TYPE_1, pm.PROMPT_ACTION],
+      [principal, PERM_TYPE_1, pm.ALLOW_ACTION],
+    ]
+  );
+  check_enumerator(
+    [PERM_TYPE_1, PERM_TYPE_2],
+    [
+      [subPrincipal, PERM_TYPE_1, pm.PROMPT_ACTION],
+      [principal, PERM_TYPE_1, pm.ALLOW_ACTION],
+    ]
+  );
+  check_enumerator([], []);
+  check_enumerator([PERM_TYPE_2], []);
+
+  pm.addFromPrincipal(principal, PERM_TYPE_2, pm.PROMPT_ACTION);
+  check_enumerator(
+    [PERM_TYPE_1, PERM_TYPE_2],
+    [
+      [subPrincipal, PERM_TYPE_1, pm.PROMPT_ACTION],
+      [principal, PERM_TYPE_1, pm.ALLOW_ACTION],
+      [principal, PERM_TYPE_2, pm.PROMPT_ACTION],
+    ]
+  );
+  check_enumerator([], []);
+  check_enumerator([PERM_TYPE_2], [[principal, PERM_TYPE_2, pm.PROMPT_ACTION]]);
+
+  info("check that UNKNOWN_ACTION permissions are ignored");
+  pm.addFromPrincipal(subPrincipal, PERM_TYPE_2, pm.UNKNOWN_ACTION);
+  check_enumerator([PERM_TYPE_2], [[principal, PERM_TYPE_2, pm.PROMPT_ACTION]]);
+
+  info("check that permission updates are reflected");
+  pm.addFromPrincipal(subPrincipal, PERM_TYPE_2, pm.PROMPT_ACTION);
+  check_enumerator(
+    [PERM_TYPE_2],
+    [
+      [subPrincipal, PERM_TYPE_2, pm.PROMPT_ACTION],
+      [principal, PERM_TYPE_2, pm.PROMPT_ACTION],
+    ]
+  );
+
+  info("check that permission removals are reflected");
+  pm.removeFromPrincipal(principal, PERM_TYPE_1);
+  check_enumerator(
+    [PERM_TYPE_1],
+    [[subPrincipal, PERM_TYPE_1, pm.PROMPT_ACTION]]
+  );
+
+  pm.removeAll();
+  check_enumerator([], []);
+  check_enumerator([PERM_TYPE_1], []);
+  check_enumerator([PERM_TYPE_2], []);
+  check_enumerator([PERM_TYPE_1, PERM_TYPE_2], []);
+}
diff --git a/extensions/permissions/test/unit/xpcshell.ini b/extensions/permissions/test/unit/xpcshell.ini
index 47456e59fc5a..4a29a3cbf88f 100644
--- a/extensions/permissions/test/unit/xpcshell.ini
+++ b/extensions/permissions/test/unit/xpcshell.ini
@@ -5,6 +5,7 @@ head = head.js
 [test_permmanager_defaults.js]
 [test_permmanager_expiration.js]
 skip-if = win10_2004 # Bug 1718292
+[test_permmanager_getAllByTypes.js]
 [test_permmanager_getAllByTypeSince.js]
 [test_permmanager_getAllForPrincipal.js]
 [test_permmanager_getAllWithTypePrefix.js]
diff --git a/netwerk/base/nsIPermissionManager.idl b/netwerk/base/nsIPermissionManager.idl
index db71e2188157..32f75f241d20 100644
--- a/netwerk/base/nsIPermissionManager.idl
+++ b/netwerk/base/nsIPermissionManager.idl
@@ -82,6 +82,17 @@ interface nsIPermissionManager : nsISupports
    */
   Array<nsIPermission> getAllWithTypePrefix(in ACString prefix);
 
+
+  /**
+   * Get all custom permissions whose type exactly match one of the types defined
+   * in the passed array argument.
+   * This will return an array of all permissions which are not set to default.
+   *
+   * @param types  an array of case-sensitive ASCII strings, identifying the 
+   *               permissions to be matched.
+   */
+  Array<nsIPermission> getAllByTypes(in Array<ACString> types);
+
   /**
    * Get all custom permissions of a specific type and that were modified after
    * the specified date. This will return an array of all permissions which are