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memcpy(NULL, NULL, 0) in array_new() #66795

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jwilk mannequin opened this issue Oct 10, 2014 · 3 comments
Closed

memcpy(NULL, NULL, 0) in array_new() #66795

jwilk mannequin opened this issue Oct 10, 2014 · 3 comments
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stdlib Python modules in the Lib dir

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@jwilk
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jwilk mannequin commented Oct 10, 2014

BPO 22605
Nosy @jwilk
Files
  • 229023.patch
    		•

    Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

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    GitHub fields:

    assignee = None
closed_at = <Date 2014-10-11.00:58:50.265>
created_at = <Date 2014-10-10.19:15:10.423>
labels = ['library']
title = 'memcpy(NULL, NULL, 0) in array_new()'
updated_at = <Date 2014-10-11.00:58:50.224>
user = 'https://github.com/jwilk'

    bugs.python.org fields:

    activity = <Date 2014-10-11.00:58:50.224>
actor = 'python-dev'
assignee = 'none'
closed = True
closed_date = <Date 2014-10-11.00:58:50.265>
closer = 'python-dev'
components = ['Library (Lib)']
creation = <Date 2014-10-10.19:15:10.423>
creator = 'jwilk'
dependencies = []
files = ['36871']
hgrepos = []
issue_num = 22605
keywords = ['patch']
message_count = 3.0
messages = ['229023', '229024', '229054']
nosy_count = 2.0
nosy_names = ['jwilk', 'python-dev']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue22605'
versions = ['Python 3.5']
    @jwilk jwilk mannequin added the stdlib Python modules in the Lib dir label Oct 10, 2014
    @jwilk
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    jwilk mannequin commented Oct 10, 2014

    If you initialize array with another empty array, then this code runs:

    memcpy(self->ob_item, other->ob_item, len * other->ob_descr->itemsize);

    But self->ob_item and other->ob_item are NULL in such case.
    Passing null pointer to memcpy() is undefined behavior even when length is 0.

    @jwilk jwilk mannequin changed the title memcpy(NULL, NULL, 0) in memcpy(NULL, NULL, 0) in array_new() Oct 10, 2014
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    jwilk mannequin commented Oct 10, 2014

    The attached patch should fix the bug.

    @python-dev
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    python-dev mannequin commented Oct 11, 2014

    New changeset 4563fff4e099 by Benjamin Peterson in branch '3.4':
    prevent passing NULL to memcpy (closes bpo-22605)
    https://hg.python.org/cpython/rev/4563fff4e099

    New changeset 8165e44594c2 by Benjamin Peterson in branch 'default':
    merge 3.4 (closes bpo-22605)
    https://hg.python.org/cpython/rev/8165e44594c2

    @python-dev python-dev mannequin closed this as completed Oct 11, 2014
    @ezio-melotti ezio-melotti transferred this issue from another repository Apr 10, 2022
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