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fix: ServiceTag %ls buffer overread in Profile UI (stack corruption) #6

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fix: ServiceTag %ls buffer overread in Profile UI (stack corruption) #6

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13 changes: 12 additions & 1 deletion src/mcc/CUserProfile.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4,13 +4,24 @@

#include "imgui.h"
#include <cstdio>
#include <cstring>
#include <cwchar>

void CUserProfile::ImGuiContext() {
bool result = false;
char buffer[1024];

sprintf(buffer, "%ls", ServiceTag);
// ServiceTag is a fixed wchar_t[4] with NO null terminator - a real
// 4-character tag fills every slot, so printing it with %ls reads past
// the array and can smash the stack buffer. Convert through a
// null-terminated copy instead.
wchar_t tagCopy[5] = {};
memcpy(tagCopy, ServiceTag, sizeof(ServiceTag));
snprintf(buffer, sizeof(buffer), "%ls", tagCopy);
if (ImGui::InputText("ServiceTag", buffer, 5, ImGuiInputTextFlags_CallbackCompletion)) {
// Clear first: shortening a tag must not leave stale trailing
// characters (which would recreate an unterminated 4-char tag).
wmemset(ServiceTag, 0, 4);
for (int i = 0; i < 4; ++i) {
if (buffer[i] == 0) break;
ServiceTag[i] = buffer[i];
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