Mercurial > cpython-lru_cache-weakref
diff Lib/cgi.py @ 39437:864172515ee7 2.4
Chris McDonough's patch to defend against certain DoS attacks on FieldStorage.
SF bug #1112549. (backport from rev. 51190)
| author | Georg Brandl <georg@python.org> |
|---|---|
| date | Fri, 11 Aug 2006 07:14:38 +0000 |
| parents | 846ba2972d7c |
| children |
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--- a/Lib/cgi.py Wed Aug 09 07:15:29 2006 +0000 +++ b/Lib/cgi.py Fri Aug 11 07:14:38 2006 +0000 @@ -247,6 +247,10 @@ XXX This should really be subsumed by FieldStorage altogether -- no point in having two implementations of the same parsing algorithm. + Also, FieldStorage protects itself better against certain DoS attacks + by limiting the size of the data read in one chunk. The API here + does not support that kind of protection. This also affects parse() + since it can call parse_multipart(). """ boundary = "" @@ -695,7 +699,7 @@ def read_lines_to_eof(self): """Internal: read lines until EOF.""" while 1: - line = self.fp.readline() + line = self.fp.readline(1<<16) if not line: self.done = -1 break @@ -706,12 +710,13 @@ next = "--" + self.outerboundary last = next + "--" delim = "" + last_line_lfend = True while 1: - line = self.fp.readline() + line = self.fp.readline(1<<16) if not line: self.done = -1 break - if line[:2] == "--": + if line[:2] == "--" and last_line_lfend: strippedline = line.strip() if strippedline == next: break @@ -722,11 +727,14 @@ if line[-2:] == "\r\n": delim = "\r\n" line = line[:-2] + last_line_lfend = True elif line[-1] == "\n": delim = "\n" line = line[:-1] + last_line_lfend = True else: delim = "" + last_line_lfend = False self.__write(odelim + line) def skip_lines(self): @@ -735,18 +743,20 @@ return next = "--" + self.outerboundary last = next + "--" + last_line_lfend = True while 1: - line = self.fp.readline() + line = self.fp.readline(1<<16) if not line: self.done = -1 break - if line[:2] == "--": + if line[:2] == "--" and last_line_lfend: strippedline = line.strip() if strippedline == next: break if strippedline == last: self.done = 1 break + last_line_lfend = line.endswith('\n') def make_file(self, binary=None): """Overridable: return a readable & writable file.