Skip to main content

Browse the archive

Staging
v0.5.1
https://github.com/python/cpython
09 December 2020, 11:06:31 UTC
Revision 30e769382dfb67a68fe8e6bfe8509addb4aa9514 authored by Miss Islington (bot) on 04 February 2020, 21:41:55 UTC, committed by GitHub on 04 February 2020, 21:41:55 UTC 
closes bpo-39510: Fix use-after-free in BufferedReader.readinto() (GH-18295)
 

When called on a closed object, readinto() segfaults on account
of a write to a freed buffer:

    ==220553== Process terminating with default action of signal 11 (SIGSEGV): dumping core
    ==220553==  Access not within mapped region at address 0x2A
    ==220553==    at 0x48408A0: memmove (vg_replace_strmem.c:1272)
    ==220553==    by 0x58DB0C: _buffered_readinto_generic (bufferedio.c:972)
    ==220553==    by 0x58DCBA: _io__Buffered_readinto_impl (bufferedio.c:1053)
    ==220553==    by 0x58DCBA: _io__Buffered_readinto (bufferedio.c.h:253)

Reproducer:

    reader = open ("/dev/zero", "rb")
    _void  = reader.read (42)
    reader.close ()
    reader.readinto (bytearray (42)) GH-GH-GH- BANG!

The problem exists since 2012 when commit dc469454ec added code
to free the read buffer on close().

Signed-off-by: Philipp Gesang <philipp.gesang@intra2net.com>
(cherry picked from commit cb1c0746f277052e45a60d6c436a765e34722821)

Co-authored-by: Philipp Gesang <phg@phi-gamma.net>
1 parent 9a740b6
History
Tip revision: 30e769382dfb67a68fe8e6bfe8509addb4aa9514 authored by Miss Islington (bot) on 04 February 2020, 21:41:55 UTC
closes bpo-39510: Fix use-after-free in BufferedReader.readinto() (GH-18295)
Tip revision: 30e7693
File Mode Size
Grammar -rw-r--r-- 9.6 KB
Tokens -rw-r--r-- 1.5 KB
back to top