Apache scoreboard invalid free on shutdown in master process

[halfdog <me () halfdog net>]

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Hello List,

Modification of apache scoreboard data, shared by root (uid=0) and
www-data process, allows triggering of invalid free in root process
during apache shutdown, exploitation seems impossible except for really
broken chroot configs.

The free is triggered by setting the scoreboard type from
shared-mem-type to malloc-type. This is possible because the
scoreboard type setting is also stored in shared memory and hence
changeable by lower-privileged worker process.

See
http://www.halfdog.net/Security/2011/ApacheScoreboardInvalidFreeOnShutdown/

- -- 
http://www.halfdog.net/
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