zulip/zerver/lib/unminify.py

71 lines
3.0 KiB
Python

import re
import os
import sourcemap
from typing import Dict, List
from zerver.lib.pysa import mark_sanitized
class SourceMap:
'''Map (line, column) pairs from generated to source file.'''
def __init__(self, sourcemap_dirs: List[str]) -> None:
self._dirs = sourcemap_dirs
self._indices: Dict[str, sourcemap.SourceMapDecoder] = {}
def _index_for(self, minified_src: str) -> sourcemap.SourceMapDecoder:
'''Return the source map index for minified_src, loading it if not
already loaded.'''
# Prevent path traversal
assert ".." not in minified_src and "/" not in minified_src
if minified_src not in self._indices:
for source_dir in self._dirs:
filename = os.path.join(source_dir, minified_src + '.map')
if os.path.isfile(filename):
# Use 'mark_sanitized' to force Pysa to ignore the fact that
# 'filename' is user controlled. While putting user
# controlled data into a filesystem operation is bad, in
# this case it's benign because 'filename' can't traverse
# directories outside of the pre-configured 'sourcemap_dirs'
# (due to the above assertions) and will always end in
# '.map'. Additionally, the result of this function is used
# for error logging and not returned to the user, so
# controlling the loaded file would not be useful to an
# attacker.
with open(mark_sanitized(filename)) as fp:
self._indices[minified_src] = sourcemap.load(fp)
break
return self._indices[minified_src]
def annotate_stacktrace(self, stacktrace: str) -> str:
out: str = ''
for ln in stacktrace.splitlines():
out += ln + '\n'
match = re.search(r'/static/webpack-bundles/([^:]+):(\d+):(\d+)', ln)
if match:
# Get the appropriate source map for the minified file.
minified_src = match.groups()[0]
index = self._index_for(minified_src)
gen_line, gen_col = list(map(int, match.groups()[1:3]))
# The sourcemap lib is 0-based, so subtract 1 from line and col.
try:
result = index.lookup(line=gen_line-1, column=gen_col-1)
display_src = result.src
if display_src is not None:
webpack_prefix = "webpack:///"
if display_src.startswith(webpack_prefix):
display_src = display_src[len(webpack_prefix):]
out += (' = %s line %d column %d\n' %
(display_src, result.src_line+1, result.src_col+1))
except IndexError:
out += ' [Unable to look up in source map]\n'
if ln.startswith(' at'):
out += '\n'
return out