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gh-143241: Fix infinite loop in zoneinfo._common.load_data #143243

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Merged
picnixz merged 10 commits into from
Dec 28, 2025
Merged

gh-143241: Fix infinite loop in zoneinfo._common.load_data #143243

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be21254
gh-143241: Fix infinite loop DoS in zoneinfo._common.load_data
fatihhcelik Dec 28, 2025
a240d3a
📜🤖 Added by blurb_it.
blurb-it[bot] Dec 28, 2025
4b7f241
Update Lib/test/test_zoneinfo/test_zoneinfo.py
fatihhcelik Dec 28, 2025
3691e9a
Update Lib/test/test_zoneinfo/test_zoneinfo.py
fatihhcelik Dec 28, 2025
d6f950f
📜🤖 Added by blurb_it.
blurb-it[bot] Dec 28, 2025
7f46a5b
Apply suggestions from code review
fatihhcelik Dec 28, 2025
ddd029b
gh-143241: Document ValueError for invalid files in ZoneInfo.from_file
fatihhcelik Dec 28, 2025
79042d2
Delete Misc/NEWS.d/next/Library/2025-12-28-12-38-53.gh-issue-143241.y…
fatihhcelik Dec 28, 2025
c2b00dc
Update Misc/NEWS.d/next/Library/2025-12-28-13-49-06.gh-issue-143241.5…
fatihhcelik Dec 28, 2025
af90693
gh-143241: Add Patch by credit to NEWS
fatihhcelik Dec 28, 2025
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2 changes: 2 additions & 0 deletions Lib/test/test_zoneinfo/test_zoneinfo.py
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Original file line number Diff line number Diff line change
Expand Up @@ -252,6 +252,8 @@ def test_bad_zones(self):
bad_zones = [
b"", # Empty file
b"AAAA3" + b" " * 15, # Bad magic
# Truncated V2 file (infinite loop DoS)
b"TZif2" + (b"\x00" * 39) + b"TZif2" + (b"\x00" * 39) + b"\n" + b"Part",
]

for bad_zone in bad_zones:
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6 changes: 4 additions & 2 deletions Lib/zoneinfo/_common.py
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Original file line number Diff line number Diff line change
Expand Up @@ -119,8 +119,10 @@ def get_abbr(idx):
assert c == b"\n", c

tz_bytes = b""
while (c := fobj.read(1)) != b"\n":
tz_bytes += c
line = fobj.readline()
if not line.endswith(b"\n"):
raise ValueError("Invalid TZif file: unexpected end of file")
tz_bytes = line.rstrip(b"\n")

tz_str = tz_bytes
else:
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