From 178317b2525ce150215a89e21b7d88013ee35a1d Mon Sep 17 00:00:00 2001
From: Mikhail Naganov <mnaganov@google.com>
Date: Fri, 19 Feb 2021 14:08:52 -0800
Subject: [PATCH] audio: Put stronger rules on vendor extension enums

The namespace part has been made mandatory. The namespace
must be at least 3 characters.

Bug: 176144684
Test: atest android.hardware.audio.common@7.0-util_tests
Test: atest android.hardware.audio@7.0-util_tests
Test: atest android.hardware.audio.effect@7.0-util_tests
Change-Id: If8578dfab80b51d9c30042e99bfbf70f40598afa
---
 audio/7.0/config/audio_policy_configuration.xsd    | 14 +++++++++-----
 ...android_audio_policy_configuration_V7_0-enums.h | 12 +++++-------
 .../all-versions/default/tests/hidlutils_tests.cpp |  6 ++++++
 3 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/audio/7.0/config/audio_policy_configuration.xsd b/audio/7.0/config/audio_policy_configuration.xsd
index 531572b777..ccaaf98288 100644
--- a/audio/7.0/config/audio_policy_configuration.xsd
+++ b/audio/7.0/config/audio_policy_configuration.xsd
@@ -310,13 +310,17 @@
         </xs:restriction>
     </xs:simpleType>
     <xs:simpleType name="vendorExtension">
-        <!-- Vendor extension names must be prefixed by "VX_" to distinguish them from AOSP values.
-             Vendor are encouraged to namespace their module names to avoid conflicts.
-             Example for an hypothetical Google virtual reality device:
-                <devicePort tagName="VR" type="VX_GOOGLE_VR" role="sink">
+        <!-- Vendor extension names must be prefixed by "VX_" to distinguish them from
+             AOSP values. Vendors must namespace their names to avoid conflicts. The
+             namespace part must only use capital latin characters and decimal digits and
+             consist of at least 3 characters. The part of the extension name after the
+             namespace may in addition include underscores. Example for a hypothetical
+             Google virtual reality device:
+
+                 <devicePort tagName="VR" type="VX_GOOGLE_VR" role="sink" />
         -->
         <xs:restriction base="xs:string">
-            <xs:pattern value="VX_[_a-zA-Z0-9]+"/>
+            <xs:pattern value="VX_[A-Z0-9]{3,}_[_A-Z0-9]+"/>
         </xs:restriction>
     </xs:simpleType>
     <xs:simpleType name="extendableAudioDevice">
diff --git a/audio/common/7.0/enums/include/android_audio_policy_configuration_V7_0-enums.h b/audio/common/7.0/enums/include/android_audio_policy_configuration_V7_0-enums.h
index b427f3a0d4..ada0d3eb9b 100644
--- a/audio/common/7.0/enums/include/android_audio_policy_configuration_V7_0-enums.h
+++ b/audio/common/7.0/enums/include/android_audio_policy_configuration_V7_0-enums.h
@@ -18,8 +18,8 @@
 #define ANDROID_AUDIO_POLICY_CONFIGURATION_V7_0_ENUMS_H
 
 #include <sys/types.h>
-#include <algorithm>
-#include <cctype>
+#include <regex>
+#include <string>
 
 #include <android_audio_policy_configuration_V7_0.h>
 
@@ -219,11 +219,9 @@ static inline bool maybeVendorExtension(const std::string& s) {
 }
 
 static inline bool isVendorExtension(const std::string& s) {
-    // Must match the "vendorExtension" rule from the XSD file.
-    static const std::string vendorPrefix = "VX_";
-    return maybeVendorExtension(s) &&
-           std::all_of(s.begin() + vendorPrefix.size(), s.end(),
-                       [](unsigned char c) { return c == '_' || std::isalnum(c); });
+    // Must be the same as the "vendorExtension" rule from the XSD file.
+    static const std::regex vendorExtension("VX_[A-Z0-9]{3,}_[_A-Z0-9]+");
+    return std::regex_match(s.begin(), s.end(), vendorExtension);
 }
 
 static inline bool isUnknownAudioChannelMask(const std::string& mask) {
diff --git a/audio/common/all-versions/default/tests/hidlutils_tests.cpp b/audio/common/all-versions/default/tests/hidlutils_tests.cpp
index ec6bdf38ef..e154453e2b 100644
--- a/audio/common/all-versions/default/tests/hidlutils_tests.cpp
+++ b/audio/common/all-versions/default/tests/hidlutils_tests.cpp
@@ -432,10 +432,16 @@ TEST(HidlUtils, ConvertDeviceType) {
 // The enums module is too small to have unit tests on its own.
 TEST(HidlUtils, VendorExtension) {
     EXPECT_TRUE(xsd::isVendorExtension("VX_GOOGLE_VR_42"));
+    EXPECT_TRUE(xsd::isVendorExtension("VX_QCM_SPK"));
     EXPECT_FALSE(xsd::isVendorExtension(""));
     EXPECT_FALSE(xsd::isVendorExtension("random string"));
     EXPECT_FALSE(xsd::isVendorExtension("VX_"));
+    EXPECT_FALSE(xsd::isVendorExtension("VX_X"));
+    EXPECT_FALSE(xsd::isVendorExtension("VX_X_"));
+    EXPECT_FALSE(xsd::isVendorExtension("VX_X_X"));
+    EXPECT_FALSE(xsd::isVendorExtension("VX_XX_X"));
     EXPECT_FALSE(xsd::isVendorExtension("VX_GOOGLE_$$"));
+    EXPECT_FALSE(xsd::isVendorExtension("VX_$CM_SPK"));
 }
 
 TEST(HidlUtils, ConvertInvalidDeviceAddress) {