From b7d08bc04a4296982fcef8b6b8a354a9e4e7afca Mon Sep 17 00:00:00 2001
From: Frank Tang <ftang@chromium.org>
Date: Sat, 1 Feb 2020 02:39:04 +0000
Subject: [PATCH] ICU-20958 Prevent SEGV_MAPERR in append
See #971
---
source/common/unistr.cpp | 6 ++-
source/test/intltest/ustrtest.cpp | 62 +++++++++++++++++++++++++
source/test/intltest/ustrtest.h | 1 +
3 files changed, 68 insertions(+), 1 deletion(-)
diff --git source/common/unistr.cpp source/common/unistr.cpp
index 901bb3358ba..077b4d6ef20 100644
--- source/common/unistr.cpp
+++ source/common/unistr.cpp
@@ -1563,7 +1563,11 @@ UnicodeString::doAppend(const UChar *srcChars, int32_t srcStart, int32_t srcLeng
}
int32_t oldLength = length();
- int32_t newLength = oldLength + srcLength;
+ int32_t newLength;
+ if (uprv_add32_overflow(oldLength, srcLength, &newLength)) {
+ setToBogus();
+ return *this;
+ }
// Check for append onto ourself
const UChar* oldArray = getArrayStart();
diff --git source/test/intltest/ustrtest.cpp source/test/intltest/ustrtest.cpp
index b6515ea813c..ad38bdf53a3 100644
--- source/test/intltest/ustrtest.cpp
+++ source/test/intltest/ustrtest.cpp
@@ -67,6 +67,7 @@ void UnicodeStringTest::runIndexedTest( int32_t index, UBool exec, const char* &
TESTCASE_AUTO(TestWCharPointers);
TESTCASE_AUTO(TestNullPointers);
TESTCASE_AUTO(TestUnicodeStringInsertAppendToSelf);
+ TESTCASE_AUTO(TestLargeAppend);
TESTCASE_AUTO_END;
}
@@ -2310,3 +2311,64 @@ void UnicodeStringTest::TestUnicodeStringInsertAppendToSelf() {
str.insert(2, sub);
assertEquals("", u"abbcdcde", str);
}
+
+void UnicodeStringTest::TestLargeAppend() {
+ if(quick) return;
+
+ IcuTestErrorCode status(*this, "TestLargeAppend");
+ // Make a large UnicodeString
+ int32_t len = 0xAFFFFFF;
+ UnicodeString str;
+ char16_t *buf = str.getBuffer(len);
+ // A fast way to set buffer to valid Unicode.
+ // 4E4E is a valid unicode character
+ uprv_memset(buf, 0x4e, len * 2);
+ str.releaseBuffer(len);
+ UnicodeString dest;
+ // Append it 16 times
+ // 0xAFFFFFF times 16 is 0xA4FFFFF1,
+ // which is greater than INT32_MAX, which is 0x7FFFFFFF.
+ int64_t total = 0;
+ for (int32_t i = 0; i < 16; i++) {
+ dest.append(str);
+ total += len;
+ if (total <= INT32_MAX) {
+ assertFalse("dest is not bogus", dest.isBogus());
+ } else {
+ assertTrue("dest should be bogus", dest.isBogus());
+ }
+ }
+ dest.remove();
+ total = 0;
+ for (int32_t i = 0; i < 16; i++) {
+ dest.append(str);
+ total += len;
+ if (total + len <= INT32_MAX) {
+ assertFalse("dest is not bogus", dest.isBogus());
+ } else if (total <= INT32_MAX) {
+ // Check that a string of exactly the maximum size works
+ UnicodeString str2;
+ int32_t remain = INT32_MAX - total;
+ char16_t *buf2 = str2.getBuffer(remain);
+ if (buf2 == nullptr) {
+ // if somehow memory allocation fail, return the test
+ return;
+ }
+ uprv_memset(buf2, 0x4e, remain * 2);
+ str2.releaseBuffer(remain);
+ dest.append(str2);
+ total += remain;
+ assertEquals("When a string of exactly the maximum size works", (int64_t)INT32_MAX, total);
+ assertEquals("When a string of exactly the maximum size works", INT32_MAX, dest.length());
+ assertFalse("dest is not bogus", dest.isBogus());
+
+ // Check that a string size+1 goes bogus
+ str2.truncate(1);
+ dest.append(str2);
+ total++;
+ assertTrue("dest should be bogus", dest.isBogus());
+ } else {
+ assertTrue("dest should be bogus", dest.isBogus());
+ }
+ }
+}
diff --git source/test/intltest/ustrtest.h source/test/intltest/ustrtest.h
index 218befdcc68..4a356a92c7a 100644
--- source/test/intltest/ustrtest.h
+++ source/test/intltest/ustrtest.h
@@ -97,6 +97,7 @@ class UnicodeStringTest: public IntlTest {
void TestWCharPointers();
void TestNullPointers();
void TestUnicodeStringInsertAppendToSelf();
+ void TestLargeAppend();
};
#endif
