Since this module is used as a fallback in case no built-in modules
have been configured, string.atof() should not fail when "import re"
fails (usually because pcre is not there).
This opens up a tiny security hole: *if* an attacker can make "import
re" fail, they can also make string.atof(arbitrary_string) evaluate
the arbitrary string. Nothing to keep me awake at night...
diff --git a/Lib/string.py b/Lib/string.py
index 2139a75..8c64952 100644
--- a/Lib/string.py
+++ b/Lib/string.py
@@ -203,7 +203,11 @@
def atof(str):
global re
if re is None:
- import re
+ # Don't fail if re doesn't exist -- just skip the syntax check
+ try:
+ import re
+ except ImportError:
+ re = 0
sign = ''
s = strip(str)
if s and s[0] in '+-':
@@ -212,10 +216,10 @@
if not s:
raise ValueError, 'non-float argument to string.atof'
while s[0] == '0' and len(s) > 1 and s[1] in digits: s = s[1:]
- if not re.match('[0-9]*(\.[0-9]*)?([eE][-+]?[0-9]+)?$', s):
+ if re and not re.match('[0-9]*(\.[0-9]*)?([eE][-+]?[0-9]+)?$', s):
raise ValueError, 'non-float argument to string.atof'
try:
- return float(eval(sign + s))
+ return float(eval(sign + s, {}))
except SyntaxError:
raise ValueError, 'non-float argument to string.atof'
diff --git a/Lib/stringold.py b/Lib/stringold.py
index 2139a75..8c64952 100644
--- a/Lib/stringold.py
+++ b/Lib/stringold.py
@@ -203,7 +203,11 @@
def atof(str):
global re
if re is None:
- import re
+ # Don't fail if re doesn't exist -- just skip the syntax check
+ try:
+ import re
+ except ImportError:
+ re = 0
sign = ''
s = strip(str)
if s and s[0] in '+-':
@@ -212,10 +216,10 @@
if not s:
raise ValueError, 'non-float argument to string.atof'
while s[0] == '0' and len(s) > 1 and s[1] in digits: s = s[1:]
- if not re.match('[0-9]*(\.[0-9]*)?([eE][-+]?[0-9]+)?$', s):
+ if re and not re.match('[0-9]*(\.[0-9]*)?([eE][-+]?[0-9]+)?$', s):
raise ValueError, 'non-float argument to string.atof'
try:
- return float(eval(sign + s))
+ return float(eval(sign + s, {}))
except SyntaxError:
raise ValueError, 'non-float argument to string.atof'