%e in /proc/sys/kernel/core_pattern and empty current->comm

From: Earl Chew
Date: Sun Aug 28 2011 - 12:50:05 EST


It is possible to set /proc/sys/kernel/core_pattern to %e:

echo '%e' > /proc/sys/kernel/core_pattern


A couple of interesting effects:

a. Cores will tend to try to overwrite the executable.

Is this considered an issue ?


b. Apparently it seems possible to set current->comm to be empty:

prctl(PR_SET_NAME, "", 0, 0, 0);

No core dump is generated since the resulting corename is empty,
and filp_open() fails.

Is this considered a defect, or potential security concern ?


c. Consequential to (b), setting /proc/sys/kernel/core_pattern to empty
and /proc/sys/kernel/core_uses_pid to zero universally prevents
core dumps.

I'm wondering if this behaviour is provided intentionally.


Earl

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