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enable hash randomization by default

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Benjamin Peterson 2012-02-21 16:08:05 -05:00
parent 6ca5a4d49f
commit c9f54cf512
9 changed files with 44 additions and 65 deletions
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23
Misc/python.man
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@ -37,9 +37,6 @@ python \- an interpreted, interactive, object-oriented programming language
.B \-OO
]
[
.B \-R
]
[
.B \-s
]
[
@ -151,18 +148,6 @@ Discard docstrings in addition to the \fB-O\fP optimizations.
Do not print the version and copyright messages. These messages are
also suppressed in non-interactive mode.
.TP
.B \-R
Turn on "hash randomization", so that the hash() values of str, bytes and
datetime objects are "salted" with an unpredictable pseudo-random value.
Although they remain constant within an individual Python process, they are
not predictable between repeated invocations of Python.
.IP
This is intended to provide protection against a denial of service
caused by carefully-chosen inputs that exploit the worst case performance
of a dict insertion, O(n^2) complexity. See
http://www.ocert.org/advisories/ocert-2011-003.html
for details.
.TP
.B \-s
Don't add user site directory to sys.path.
.TP
@ -418,9 +403,8 @@ specifying \fB\-v\fP multiple times.
If this is set to a comma-separated string it is equivalent to
specifying the \fB\-W\fP option for each separate value.
.IP PYTHONHASHSEED
If this variable is set to "random", the effect is the same as specifying
the \fB-R\fP option: a random value is used to seed the hashes of str,
bytes and datetime objects.
If this variable is set to "random", a random value is used to seed the hashes
of str, bytes and datetime objects.
If PYTHONHASHSEED is set to an integer value, it is used as a fixed seed for
generating the hash() of the types covered by the hash randomization. Its
@ -429,8 +413,7 @@ interpreter itself, or to allow a cluster of python processes to share hash
values.
The integer must be a decimal number in the range [0,4294967295]. Specifying
the value 0 will lead to the same hash values as when hash randomization is
disabled.
the value 0 will disable hash randomization.
.SH AUTHOR
The Python Software Foundation: http://www.python.org/psf
.SH INTERNET RESOURCES