FazBrowse GitHub Viewer | Trending |
URL:
| Home
Tools: [Download Repo ZIP]   [Original HTTPS Page]

bpo-45507: Throw EOF error when gzip headers or trailers are truncated by rhpvorderman · Pull Request #29023 · python/cpython · GitHub

/ cpython Public

bpo-45507: Throw EOF error when gzip headers or trailers are truncated #29023

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
rhpvorderman wants to merge 2 commits into from
Conversation 2 Commits 2 Checks 0 Files changed
Closed

bpo-45507: Throw EOF error when gzip headers or trailers are truncated #29023

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
83e58a2
Throw EOF error when trailer is not present in gzip member
rhpvorderman Oct 18, 2021
773c4f1
Fix bug where missing NAME or COMMENt fields do not trigger an error
rhpvorderman Oct 18, 2021
File filter

Filter by extension

Filter by extension .py  (2) .rst  (1) All 2 file types selected
Viewed files
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Unified
Split
Hide whitespace
Diff view
Unified
Split
Hide whitespace
11 changes: 7 additions & 4 deletions Lib/gzip.py
Show comments
View file
Open in desktop
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode characters
Show hidden characters
Original file line number Diff line number Diff line change
Expand Up @@ -442,14 +442,14 @@ def _read_gzip_header(fp):
if flag & FNAME:
# Read and discard a null-terminated string containing the filename
while True:
s = fp.read(1)
if not s or s==b'\000':
s = _read_exact(fp, 1)
if s == b'\000':
break
if flag & FCOMMENT:
# Read and discard a null-terminated string containing a comment
while True:
s = fp.read(1)
if not s or s==b'\000':
s = _read_exact(fp, 1)
if s == b'\000':
break
if flag & FHCRC:
_read_exact(fp, 2) # Read & discard the 16-bit header CRC
Expand Down Expand Up @@ -607,6 +607,9 @@ def decompress(data):
do = zlib.decompressobj(wbits=-zlib.MAX_WBITS)
# Read all the data except the header
decompressed = do.decompress(data[fp.tell():])
if not do.eof or len(do.unused_data) < 8:
raise EOFError("Compressed file ended before the end-of-stream "
"marker was reached")
crc, length = struct.unpack("<II", do.unused_data[:8])
if crc != zlib.crc32(decompressed):
raise BadGzipFile("CRC check failed")
Expand Down
14 changes: 14 additions & 0 deletions Lib/test/test_gzip.py
Show comments
View file
Open in desktop
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode characters
Show hidden characters
Original file line number Diff line number Diff line change
Expand Up @@ -562,6 +562,20 @@ def test_decompress(self):
datac = gzip.compress(data)
self.assertEqual(gzip.decompress(datac), data)

def test_truncated_header(self):
truncated_headers = [
b"\x1f\x8b\x08\x00\x00\x00\x00\x00\x00", # Missing OS byte
b"\x1f\x8b\x08\x02\x00\x00\x00\x00\x00\xff", # FHRC, but no checksum
b"\x1f\x8b\x08\x04\x00\x00\x00\x00\x00\xff", # FEXTRA, but no xlen
b"\x1f\x8b\x08\x04\x00\x00\x00\x00\x00\xff\xaa\x00", # FEXTRA, xlen, but no data
b"\x1f\x8b\x08\x08\x00\x00\x00\x00\x00\xff", # FNAME but no fname
b"\x1f\x8b\x08\x10\x00\x00\x00\x00\x00\xff", # FCOMMENT, but no fcomment
]
for header in truncated_headers:
with self.subTest(header=header):
self.assertRaises(EOFError, gzip._read_gzip_header,
io.BytesIO(header))

def test_read_truncated(self):
data = data1*50
# Drop the CRC (4 bytes) and file size (4 bytes).
Expand Down
3 changes: 3 additions & 0 deletions Misc/NEWS.d/next/Library/2021-10-18-11-20-24.bpo-45507.vWx2yS.rst
Show comments
View file
Open in desktop
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode characters
Show hidden characters
Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
Make sure EOFerror is thrown when gzip headers have missing or truncated
NAME or COMMENT fields when FNAME or FCOMMENT flags are set.

Back | FazBrowse Home | New Git URL