[CVE-2019-9674] bpo-36258: Add pitfalls to zipfile module documentation

We saw vulnerability warning description (including zip bomb) in Doc/library/xml.rst file.
This gave us the idea of documentation improvement.

So, we moved a little bit forward :P
And the doc patch can be found (pr).

Change-Id: Ib91b006010ce69b5a49525cb2c27a3ea1bdb7ec6
Signed-off-by: JinWang An <jinwang.an@samsung.com>

diff --git a/Doc/library/zipfile.rst b/Doc/library/zipfile.rst
index ba613b3..77a29fb 100644 (file)
--- a/Doc/library/zipfile.rst
+++ b/Doc/library/zipfile.rst
@@ -553,5 +553,45 @@ Command-line options
 
    Test whether the zipfile is valid or not.
 
+Decompression pitfalls
+----------------------
+
+The extraction in zipfile module might fail due to some pitfalls listed below.
+
+From file itself
+~~~~~~~~~~~~~~~~
+
+Decompression may fail due to incorrect password / CRC checksum / ZIP format or
+unsupported compression method / decryption.
+
+File System limitations
+~~~~~~~~~~~~~~~~~~~~~~~
+
+Exceeding limitations on different file systems can cause decompression failed.
+Such as allowable characters in the directory entries, length of the file name,
+length of the pathname, size of a single file, and number of files, etc.
+
+Resources limitations
+~~~~~~~~~~~~~~~~~~~~~
+
+The lack of memory or disk volume would lead to decompression
+failed. For example, decompression bombs (aka `ZIP bomb`_)
+apply to zipfile library that can cause disk volume exhaustion.
+
+Interruption
+~~~~~~~~~~~~
+
+Interruption during the decompression, such as pressing control-C or killing the
+decompression process may result in incomplete decompression of the archive.
+
+Default behaviors of extraction
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Not knowing the default extraction behaviors
+can cause unexpected decompression results.
+For example, when extracting the same archive twice,
+it overwrites files without asking.
+
 
+.. _ZIP bomb: https://en.wikipedia.org/wiki/Zip_bomb
 .. _PKZIP Application Note: https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT