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fix oob read in getSpelling when node has no ext tokens #8907

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fix oob read in getSpelling when node has no ext tokens #8907

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2 changes: 2 additions & 0 deletions lib/clangimport.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -431,6 +431,8 @@ std::string clangimport::AstNode::getSpelling() const
if (typeIndex <= 0)
return "";
}
if (typeIndex <= 0)
return "";
Comment on lines +434 to +435

@danmar danmar Oct 1, 2026

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This is an AI review. Take it with a grain of salt and feel free to reject it by resolving the comment.

The fix looks correct. I verified that the new crash2 test fails on main (built with -D_GLIBCXX_ASSERTIONS: Assertion '__n < this->size()' failed in getSpelling()) and passes with this PR.

The description says the guard is hoisted, but the two existing if (typeIndex <= 0) return ""; checks in the FunctionDecl/CXXConstructorDecl/CXXMethodDecl and DeclRefExpr branches above are kept. They are now redundant, since this new check covers them. Maybe remove them so there is only one guard? I tried that locally and TestClangImport still passes.

const std::string &str = mExtTokens[typeIndex - 1];
if (startsWith(str,"col:"))
return "";
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8 changes: 8 additions & 0 deletions test/testclangimport.cpp
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Expand Up @@ -139,6 +139,7 @@ class TestClangImport : public TestFixture {
TEST_CASE(valueType2);

TEST_CASE(crash);
TEST_CASE(crash2);
}

std::string parse(const char clang[]) {
Expand Down Expand Up @@ -1372,6 +1373,13 @@ class TestClangImport : public TestFixture {
" `-CompoundStmt 0x5603791b5700 <col:54, col:55>\n";
(void)parse(clang); // don't crash
}

void crash2() {
// getSpelling() indexed mExtTokens[typeIndex - 1] without a lower-bound
// check, so a node whose line carries no ext tokens (typeIndex <= 0) read
// out of bounds.
(void)parse("`-RecordDecl "); // don't crash
}
};

REGISTER_TEST(TestClangImport)