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_tarfile.py: Apply fixes from Python 3.11.17 #2198

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Merged
juergbi merged 1 commit into from
Oct 12, 2026
+15 −2
Merged

_tarfile.py: Apply fixes from Python 3.11.17 #2198

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17 changes: 15 additions & 2 deletions src/buildstream/plugins/sources/_tarfile.py
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Original file line number Diff line number Diff line change
Expand Up @@ -788,6 +788,13 @@ def _get_filtered_attrs(member, dest_path, for_data=True):
# For example, 'C:/foo' on Windows.
raise AbsolutePathError(member)
# Ensure we stay in the destination
if '..' in name.replace(os.sep, '/').split('/'):
# Directories are created from the name as given, so a name that
# leaves the destination part-way through would create them
# outside it even if the resolved path stays inside.
normalized = os.path.normpath(name)
if normalized != name:
name = new_attrs['name'] = normalized
target_path = _realpath_allow_missing(os.path.join(dest_path, name))
if os.path.commonpath([target_path, dest_path]) != dest_path:
raise OutsideDestinationError(member, target_path)
Expand Down Expand Up @@ -2658,7 +2665,11 @@ def makelink_with_filter(self, tarinfo, targetpath,
return
else:
if os.path.exists(tarinfo._link_target):
os.link(tarinfo._link_target, targetpath)
# Resolve the target so the hard link points to the file
# itself. Otherwise os.link() may duplicate a symlink to a
# shallower location, where it's relative target escapes the
# destination directory. (CVE-2026-82049)
os.link(os.path.realpath(tarinfo._link_target), targetpath)
return
except symlink_exception:
keyerror_to_extracterror = True
Expand All @@ -2680,9 +2691,11 @@ def makelink_with_filter(self, tarinfo, targetpath,
"makelink_with_filter: if filter_function is not None, "
+ "extraction_root must also not be None")
try:
filter_function(
filtered = filter_function(
unfiltered.replace(name=tarinfo.name, deep=False),
extraction_root)
if filtered is None:
return
filtered = filter_function(unfiltered, extraction_root)
except _FILTER_ERRORS as cause:
raise LinkFallbackError(tarinfo, unfiltered.name) from cause
Expand Down
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