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Fix PyText_AS_UTF8/PyUnicode_AsUTF8 NULL dereference vulnerabilities #256

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Fix PyText_AS_UTF8/PyUnicode_AsUTF8 NULL dereference vulnerabilities #256

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72 changes: 62 additions & 10 deletions src/c/_cffi_backend.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2164,9 +2164,15 @@ static PyObject *cdata_repr(CDataObject *cd)
extra = " &";
else
extra = "";

const char *s_utf8 = PyText_AsUTF8(s);
if (s_utf8 == NULL) {
Py_DECREF(s);
return NULL;
}
result = PyUnicode_FromFormat("<cdata '%s%s' %s>",
cd->c_type->ct_name, extra,
PyUnicode_AsUTF8(s));
s_utf8);
Py_DECREF(s);
return result;
}
Expand All @@ -2176,8 +2182,14 @@ static PyObject *_cdata_repr2(CDataObject *cd, char *text, PyObject *x)
PyObject *res, *s = PyObject_Repr(x);
if (s == NULL)
return NULL;

const char *s_utf8 = PyText_AsUTF8(s);
if (s_utf8 == NULL) {
Py_DECREF(s);
return NULL;
}
res = PyUnicode_FromFormat("<cdata '%s' %s %s>",
cd->c_type->ct_name, text, PyUnicode_AsUTF8(s));
cd->c_type->ct_name, text, s_utf8);
Py_DECREF(s);
return res;
}
Expand Down Expand Up @@ -4488,7 +4500,14 @@ static void *b_do_dlopen(PyObject *args, const char **p_printable_filename,
return NULL;
}
*p_temp = PyUnicode_FromFormat("%p", handle);
if (*p_temp == NULL)
return NULL;
*p_printable_filename = PyUnicode_AsUTF8(*p_temp);
if (*p_printable_filename == NULL) {
Py_DECREF(*p_temp);
*p_temp = NULL;
return NULL;
}
*auto_close = 0;
return handle;
}
Expand Down Expand Up @@ -5069,8 +5088,12 @@ _add_field(PyObject *interned_fields, PyObject *fname, CTypeDescrObject *ftype,
return NULL;

if (PyDict_Size(interned_fields) != prev_size + 1) {
const char *name_utf8 = PyUnicode_AsUTF8(fname);
if (name_utf8 == NULL) {
return NULL;
}
PyErr_Format(PyExc_KeyError, "duplicate field name '%s'",
PyUnicode_AsUTF8(fname));
name_utf8);
return NULL;
}
return cf; /* borrowed reference */
Expand Down Expand Up @@ -5217,9 +5240,13 @@ static PyObject *b_complete_struct_or_union_lock_held(CTypeDescrObject *ct,
ct->ct_flags_mut |= CT_WITH_VAR_ARRAY;
}
else {
const char *fname_utf8 = PyText_AS_UTF8(fname);
if (fname_utf8 == NULL) {
goto finally;
}
PyErr_Format(PyExc_TypeError,
"field '%s.%s' has ctype '%s' of unknown size",
ct->ct_name, PyUnicode_AsUTF8(fname),
ct->ct_name, fname_utf8,
ftype->ct_name);
goto finally;
}
Expand Down Expand Up @@ -5287,9 +5314,13 @@ static PyObject *b_complete_struct_or_union_lock_held(CTypeDescrObject *ct,
if (foffset >= 0) {
/* a forced field position: ignore the offset just computed,
except to know if we must set CT_CUSTOM_FIELD_POS */
const char *fname_utf8 = PyUnicode_AsUTF8(fname);
if (fname_utf8 == NULL) {
goto finally;
}
if (detect_custom_layout(ct, sflags, byteoffset, foffset,
"wrong offset for field '",
PyUnicode_AsUTF8(fname), "'") < 0)
fname_utf8, "'") < 0)
goto finally;
byteoffset = foffset;
}
Expand Down Expand Up @@ -5333,27 +5364,40 @@ static PyObject *b_complete_struct_or_union_lock_held(CTypeDescrObject *ct,
int bits_already_occupied, bitshift;

if (foffset >= 0) {
const char *fname_utf8 = PyUnicode_AsUTF8(fname);
if (fname_utf8 == NULL) {
goto finally;
}

PyErr_Format(PyExc_TypeError,
"field '%s.%s' is a bitfield, "
"but a fixed offset is specified",
ct->ct_name, PyUnicode_AsUTF8(fname));
ct->ct_name, fname_utf8);
goto finally;
}

if (!(ftype->ct_flags & (CT_PRIMITIVE_SIGNED |
CT_PRIMITIVE_UNSIGNED |
CT_PRIMITIVE_CHAR))) {
const char *fname_utf8 = PyUnicode_AsUTF8(fname);
if (fname_utf8 == NULL) {
goto finally;
}
PyErr_Format(PyExc_TypeError,
"field '%s.%s' declared as '%s' cannot be a bit field",
ct->ct_name, PyUnicode_AsUTF8(fname),
ct->ct_name, fname_utf8,
ftype->ct_name);
goto finally;
}
if (fbitsize > 8 * ftype->ct_size) {
const char *fname_utf8 = PyUnicode_AsUTF8(fname);
if (fname_utf8 == NULL) {
goto finally;
}
PyErr_Format(PyExc_TypeError,
"bit field '%s.%s' is declared '%s:%d', which "
"exceeds the width of the type",
ct->ct_name, PyUnicode_AsUTF8(fname),
ct->ct_name, fname_utf8,
ftype->ct_name, fbitsize);
goto finally;
}
Expand All @@ -5366,9 +5410,13 @@ static PyObject *b_complete_struct_or_union_lock_held(CTypeDescrObject *ct,

if (fbitsize == 0) {
if (PyUnicode_GetLength(fname) > 0) {
const char *fname_utf8 = PyUnicode_AsUTF8(fname);
if (fname_utf8 == NULL) {
goto finally;
}
PyErr_Format(PyExc_TypeError,
"field '%s.%s' is declared with :0",
ct->ct_name, PyUnicode_AsUTF8(fname));
ct->ct_name, fname_utf8);
goto finally;
}
if (!(sflags & SF_MSVC_BITFIELDS)) {
Expand Down Expand Up @@ -5405,10 +5453,14 @@ static PyObject *b_complete_struct_or_union_lock_held(CTypeDescrObject *ct,
allowed position */
if ((sflags & SF_PACKED) &&
(bits_already_occupied & 7)) {
const char *fname_utf8 = PyUnicode_AsUTF8(fname);
if (fname_utf8 == NULL) {
goto finally;
}
PyErr_Format(PyExc_NotImplementedError,
"with 'packed', gcc would compile field "
"'%s.%s' to reuse some bits in the previous "
"field", ct->ct_name, PyUnicode_AsUTF8(fname));
"field", ct->ct_name, fname_utf8);
goto finally;
}
field_offset_bytes += falign;
Expand Down
8 changes: 7 additions & 1 deletion src/c/cglob.c
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Original file line number Diff line number Diff line change
Expand Up @@ -73,8 +73,14 @@ static void *fetch_global_var_addr(GlobSupportObject *gs)
Py_END_ALLOW_THREADS
}
if (data == NULL) {

const char *name_utf8 = PyText_AS_UTF8(gs->gs_name);
if (name_utf8 == NULL) {
return NULL;
}
PyErr_Format(FFIError, "global variable '%s' is at address NULL",
PyUnicode_AsUTF8(gs->gs_name));
name_utf8);

return NULL;
}
return data;
Expand Down
3 changes: 3 additions & 0 deletions src/c/ffi_obj.c
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Original file line number Diff line number Diff line change
Expand Up @@ -192,6 +192,9 @@ static CTypeDescrObject *_ffi_type(FFIObject *ffi, PyObject *arg,

if (x == NULL) {
const char *input_text = PyUnicode_AsUTF8(arg);
if (input_text == NULL) {
return NULL;
}
struct _cffi_parse_info_s info;
info.ctx = &ffi->types_builder.ctx;
info.output_size = FFI_COMPLEXITY_OUTPUT;
Expand Down