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ICU-23155 Fix buffer overflow in SSearchTest::offsetTest() #3546

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ICU-23155 Fix buffer overflow in SSearchTest::offsetTest() #3546

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53 changes: 31 additions & 22 deletions icu4c/source/test/intltest/ssearch.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,9 @@
#include "ssearch.h"
#include "xmlparser.h"

#include <iomanip>
#include <iostream>
#include <sstream>
#include <stdio.h> // for snprintf

char testId[100];
Expand Down Expand Up @@ -524,40 +527,48 @@ UBool OrderList::matchesAt(int32_t offset, const OrderList &other) const
return true;
}

static char *printOffsets(char *buffer, size_t n, OrderList &list)
static char* printOffsets(std::string &buffer, OrderList &list)
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@roubert roubert Nov 8, 2025

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This would all become considerably simpler if the caller wasn't required to pass in any buffer at all and the function simply returned an std::string object by value. That's what any normal C++ code would do nowadays.

{
int32_t size = list.size();
char *s = buffer;
buffer.clear();
buffer.reserve(size * 10 + 2);
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@roubert roubert Nov 8, 2025

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Is this some kind of performance optimization, to avoid having to dynamically resize the buffer? If so, I suggest removing it, this is test code, the possible performance gain is irrelevant compared to having a few extra lines of code to maintain.

std::stringstream s(buffer);

for(int32_t i = 0; i < size; i += 1) {
const Order *order = list.get(i);

if (i != 0) {
s += snprintf(s, n, ", ");
s << ", ";
}

s += snprintf(s, n, "(%d, %d)", order->lowOffset, order->highOffset);
s << "(" << order->lowOffset << ", " << order->highOffset << ")";
}

return buffer;
return buffer.data();
}

static char *printOrders(char *buffer, size_t n, OrderList &list)
static char* printOrders(std::string &buffer, OrderList &list)
{
int32_t size = list.size();
char *s = buffer;
buffer.clear();
// 10 chars is enough room for 8 hex digits plus ", "
buffer.reserve(size * 10 + 2);
std::stringstream s(buffer);

for(int32_t i = 0; i < size; i += 1) {
const Order *order = list.get(i);

if (i != 0) {
s += snprintf(s, n, ", ");
s << ", ";
}

s += snprintf(s, n, "%8.8X", order->order);
s << std::hex
<< std::uppercase
<< std::setw(8)
<< std::setfill('0')
<< order->order;
}

return buffer;
return buffer.data();
}

void SSearchTest::offsetTest()
Expand Down Expand Up @@ -631,9 +642,7 @@ void SSearchTest::offsetTest()
errcheckln(status, "Failed to create collator in offsetTest! - %s", u_errorName(status));
return;
}
char buffer[4096]; // A bit of a hack... just happens to be long enough for all the test cases...
// We could allocate one that's the right size by (CE_count * 10) + 2
// 10 chars is enough room for 8 hex digits plus ", ". 2 extra chars for "[" and "]"
std::string buffer;

col->setAttribute(UCOL_NORMALIZATION_MODE, UCOL_ON, status);

Expand Down Expand Up @@ -673,20 +682,20 @@ void SSearchTest::offsetTest()

if (forwardList.compare(backwardList)) {
logln("Works with \"%s\"", test[i]);
logln("Forward offsets: [%s]", printOffsets(buffer, sizeof(buffer), forwardList));
// logln("Backward offsets: [%s]", printOffsets(buffer, sizeof(buffer), backwardList));
logln("Forward offsets: [%s]", printOffsets(buffer, forwardList));
// logln("Backward offsets: [%s]", printOffsets(buffer, backwardList));

logln("Forward CEs: [%s]", printOrders(buffer, sizeof(buffer), forwardList));
// logln("Backward CEs: [%s]", printOrders(buffer, sizeof(buffer), backwardList));
logln("Forward CEs: [%s]", printOrders(buffer, forwardList));
// logln("Backward CEs: [%s]", printOrders(buffer, backwardList));

logln();
} else {
errln("Fails with \"%s\"", test[i]);
infoln("Forward offsets: [%s]", printOffsets(buffer, sizeof(buffer), forwardList));
infoln("Backward offsets: [%s]", printOffsets(buffer, sizeof(buffer), backwardList));
infoln("Forward offsets: [%s]", printOffsets(buffer, forwardList));
infoln("Backward offsets: [%s]", printOffsets(buffer, backwardList));

infoln("Forward CEs: [%s]", printOrders(buffer, sizeof(buffer), forwardList));
infoln("Backward CEs: [%s]", printOrders(buffer, sizeof(buffer), backwardList));
infoln("Forward CEs: [%s]", printOrders(buffer, forwardList));
infoln("Backward CEs: [%s]", printOrders(buffer, backwardList));

infoln();
}
Expand Down