commit f251c1c581f2d1b9940e60e756315c5e15443990
author Steven Moreland <smoreland@google.com> Thu May 28 00:29:08 2020 +0000
committer Steven Moreland <smoreland@google.com> Thu May 28 00:31:01 2020 +0000
tree b919076d3de2bedb553753db0ef3f56aa919f2ac
parent ddb18842b990d31fe28ac1b901e18d7fde26df35

String16::remove - avoid overflow

Bug: 156999009
Test: libutils_test (cases added)
Change-Id: Iad46d95d9848928ba81000090b2fe9aec1e5eaac

libutils/String16.cpp

diff --git a/libutils/String16.cpp b/libutils/String16.cpp
index d514f29..70bf5a0 100644
--- a/libutils/String16.cpp
+++ b/libutils/String16.cpp
@@ -441,7 +441,7 @@
         mString = getEmptyString();
         return OK;
     }
-    if ((begin+len) > N) len = N-begin;
+    if (len > N || len > N - begin) len = N - begin;
     if (begin == 0 && len == N) {
         return OK;
     }

libutils/String16_test.cpp

diff --git a/libutils/String16_test.cpp b/libutils/String16_test.cpp
index f1f24c3..ae9ba89 100644
--- a/libutils/String16_test.cpp
+++ b/libutils/String16_test.cpp
@@ -90,6 +90,13 @@
     EXPECT_STR16EQ(u"VerifyInsert me", tmp);
 }
 
+TEST(String16Test, RemoveDefault) {
+    String16 tmp("Verify me");
+    tmp.remove(4);
+    EXPECT_EQ(4U, tmp.size());
+    EXPECT_STR16EQ(u"Veri", tmp);
+}
+
 TEST(String16Test, Remove) {
     String16 tmp("Verify me");
     tmp.remove(2, 6);
@@ -97,6 +104,13 @@
     EXPECT_STR16EQ(u" m", tmp);
 }
 
+TEST(String16Test, RemoveOutOfBounds) {
+    String16 tmp("Verify me");
+    tmp.remove(100, 6);
+    EXPECT_EQ(3U, tmp.size());
+    EXPECT_STR16EQ(u" me", tmp);
+}
+
 TEST(String16Test, MakeLower) {
     String16 tmp("Verify Me!");
     tmp.makeLower();