URL:
<http://savannah.gnu.org/bugs/?51840>
Summary: Local file corruption using default retry mechanism
when retry returns no data
Project: GNU Wget
Submitted by: None
Submitted on: Thu 24 Aug 2017 03:13:30 PM UTC
Category: Program Logic
Severity: 3 - Normal
Priority: 5 - Normal
Status: None
Privacy: Public
Assigned to: None
Originator Name: Andrew Caruth
Originator Email: [email protected]
Open/Closed: Open
Discussion Lock: Any
Release: 1.18
Operating System: GNU/Linux
Reproducibility: Every Time
Fixed Release: None
Planned Release: None
Regression: None
Work Required: None
Patch Included: None
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Details:
The following server behaviour results in a corrupt local download:
1: Accept TCP connection from wget
2: Return all of the HTTP response header and N bytes of the content
3: Close the connection
(wget retry attempt 1 begins from offset N using the range header)
4: Accept TCP connection from wget
5: Close the connection
(wget retry attempt 2 begins with no byte range)
6: Return all of the HTTP response header and all of the content
7: Close the connection
The local file will now contain the bytes received in step 2 as well as all of
the bytes received in step 6.
I believe that if a 'ranged' retry receives no data, further retries should
continue to make ranged requests. Alternatively the offset in the partial file
should be reset to 0 so the next non-ranged request starts from the correct
place.
I've attached a tcpdump capture and wget debug output. The file requested is
12 bytes ("hello world!") and the resulting file is 17 bytes ("hellohello
world!").
I have also reproduced this with wget 1.13.
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File Attachments:
-------------------------------------------------------
Date: Thu 24 Aug 2017 03:13:30 PM UTC Name: wget118_corruption.pcap Size:
3KiB By: None
<http://savannah.gnu.org/bugs/download.php?file_id=41642>
-------------------------------------------------------
Date: Thu 24 Aug 2017 03:13:30 PM UTC Name: wget_debug.log Size: 3KiB By:
None
<http://savannah.gnu.org/bugs/download.php?file_id=41643>
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<http://savannah.gnu.org/bugs/?51840>
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