59 lines
1.9 KiB
Python
59 lines
1.9 KiB
Python
#!/usr/bin/env python3
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"""Guard _PyMem_DebugCheckAddress's C89 locals and validation order."""
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import re
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import sys
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from pathlib import Path
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source = Path(sys.argv[1]).read_text()
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match = re.search(
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r"\n_PyMem_DebugCheckAddress\(const char \*func, char api, const void \*p\)\s*\{(.*?)\n\}",
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source, re.S,
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)
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assert match, "_PyMem_DebugCheckAddress definition not found"
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body = re.sub(r"/\*.*?\*/", "", match.group(1), flags=re.S)
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declarations = """
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const uint8_t *q;
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size_t nbytes;
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const uint8_t *tail;
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int i;
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char id;
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"""
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assert body.split()[:len(declarations.split())] == declarations.split(), (
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"_PyMem_DebugCheckAddress must declare all locals without initializers at function entry"
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)
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# Keep the pointer cast after the assertion, and validate the leading pad
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# before reading the size or checking the tail of a possibly corrupt block.
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expected = declarations + """
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assert(p != NULL);
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q = (const uint8_t *)p;
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id = (char)q[-SST];
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if (id != api) {
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_PyObject_DebugDumpAddress(p);
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_Py_FatalErrorFormat(func,
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"bad ID: Allocated using API '%c', "
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"verified using API '%c'",
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id, api);
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}
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for (i = SST-1; i >= 1; --i) {
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if (*(q-i) != PYMEM_FORBIDDENBYTE) {
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_PyObject_DebugDumpAddress(p);
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_Py_FatalErrorFunc(func, "bad leading pad byte");
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}
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}
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nbytes = read_size_t(q - 2*SST);
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tail = q + nbytes;
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for (i = 0; i < SST; ++i) {
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if (tail[i] != PYMEM_FORBIDDENBYTE) {
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_PyObject_DebugDumpAddress(p);
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_Py_FatalErrorFunc(func, "bad trailing pad byte");
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}
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}
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"""
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assert body.split() == expected.split(), (
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"preserve _PyMem_DebugCheckAddress assertion, cast evaluation point, "
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"and complete validation/diagnostic order"
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)
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print("obmalloc _PyMem_DebugCheckAddress C89 declarations and original validation order: PASS")
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