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[2.7] bpo-30657: Check & prevent integer overflow in PyString_DecodeEscape #2174

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Merged
merged 2 commits into from
Jun 18, 2017
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[2.7] bpo-30657: Check & prevent integer overflow in PyString_DecodeEscape #2174

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[2.7] bpo-30657: Check & prevent integer overflow
jaybosamiya Jun 13, 2017
1c2659d
Add entry to Misc/NEWS and name to Misc/ACKS
jaybosamiya Jun 18, 2017
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1 change: 1 addition & 0 deletions Misc/ACKS
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Original file line number Diff line number Diff line change
Expand Up @@ -152,6 +152,7 @@ Gregory Bond
Matias Bordese
Jonas Borgström
Jurjen Bos
Jay Bosamiya
Peter Bosch
Dan Boswell
Eric Bouck
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3 changes: 3 additions & 0 deletions Misc/NEWS
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Expand Up @@ -10,6 +10,9 @@ What's New in Python 2.7.14?
Core and Builtins
-----------------

- bpo-30657: Fixed possible integer overflow in PyString_DecodeEscape.
Patch by Jay Bosamiya.

- bpo-27945: Fixed various segfaults with dict when input collections are
mutated during searching, inserting or comparing. Based on patches by
Duane Griffin and Tim Mitchell.
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8 changes: 7 additions & 1 deletion Objects/stringobject.c
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Expand Up @@ -612,7 +612,13 @@ PyObject *PyString_DecodeEscape(const char *s,
char *p, *buf;
const char *end;
PyObject *v;
Py_ssize_t newlen = recode_encoding ? 4*len:len;
Py_ssize_t newlen;
/* Check for integer overflow */
if (recode_encoding && (len > PY_SSIZE_T_MAX / 4)) {
PyErr_SetString(PyExc_OverflowError, "string is too large");
return NULL;
}
newlen = recode_encoding ? 4*len:len;
v = PyString_FromStringAndSize((char *)NULL, newlen);
if (v == NULL)
return NULL;
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