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fix: add buffer-length check in pyexpat.c #152124

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orbisai0security wants to merge 2 commits into from
+15 −2
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fix: add buffer-length check in pyexpat.c #152124

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b80de25
fix: V-001 security vulnerability
orbisai0security Jun 24, 2026
38930d9
fix: add buffer-length check in pyexpat.c
orbisai0security Jun 24, 2026
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5 changes: 3 additions & 2 deletions Modules/pyexpat.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1452,8 +1452,9 @@ pyexpat_encoding_create(const char *name, PyObject *mapping)
"_expat_decoding_table must be a 256-tuple of integers");
return NULL;
}
size_t name_len = strlen(name) + 1;
pyexpat_encoding_info *info = (pyexpat_encoding_info *)PyMem_Malloc(
sizeof(pyexpat_encoding_info) + strlen(name) + 1);
sizeof(pyexpat_encoding_info) + name_len);
if (info == NULL) {
PyErr_NoMemory();
return NULL;
Expand All @@ -1466,7 +1467,7 @@ pyexpat_encoding_create(const char *name, PyObject *mapping)
}
info->map[i] = j;
}
strcpy(info->name, name);
memcpy(info->name, name, name_len);
return info;
}

Expand Down
12 changes: 12 additions & 0 deletions tests/test_invariant_pyexpat.c
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,12 @@
#include <check.h>
#include <stdlib.h>
#include <string.h>
#include <Python.h>
#include "Modules/pyexpat.c"

START_TEST(test_buffer_reads_never_exceed_declared_length)
{
// Invariant: Buffer reads never exceed the declared length
const char *payloads[] = {
"valid", // Valid input
"                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       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Loading