[PATCH] D154708: Fix buffer overflow

[Michael Platings via Phabricator via llvm-commits]

michaelplatings created this revision.
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In practice this wasn't a problem because the overflow was into another
buffer that was immediately overwritten, but the compiler warning was
annoying.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D154708

Files:
  llvm/lib/ExecutionEngine/Orc/MachOPlatform.cpp


Index: llvm/lib/ExecutionEngine/Orc/MachOPlatform.cpp
===================================================================
--- llvm/lib/ExecutionEngine/Orc/MachOPlatform.cpp
+++ llvm/lib/ExecutionEngine/Orc/MachOPlatform.cpp
@@ -1370,7 +1370,11 @@
     DataSections.push_back({});
     auto &SD = DataSections.back();
     memset(&SD.Sec, 0, sizeof(SD.Sec));
-    strcpy(SD.Sec.sectname, "__objc_imageinfo");
+    // The terminating nul byte doesn't fit into the sectname array so use
+    // memcpy instead of strcpy. (Using strncpy causes a compiler warning).
+    const char SectName[] = "__objc_imageinfo";
+    static_assert(sizeof(SD.Sec.sectname) == sizeof(SectName) - 1);
+    memcpy(SD.Sec.sectname, SectName, sizeof(SD.Sec.sectname));
     strcpy(SD.Sec.segname, "__DATA");
     SD.Sec.size = 8;
     SD.AddFixups = [&](size_t RecordOffset) {


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