https://github.com/torvalds/linux
Revision b45c6e76bc2c72f6426c14bed64fdcbc9bf37cb0 authored by Andi Kleen on 08 January 2010, 22:42:52 UTC, committed by Linus Torvalds on 11 January 2010, 17:34:05 UTC
When print-fatal-signals is enabled it's possible to dump any memory
reachable by the kernel to the log by simply jumping to that address from
user space.

Or crash the system if there's some hardware with read side effects.

The fatal signals handler will dump 16 bytes at the execution address,
which is fully controlled by ring 3.

In addition when something jumps to a unmapped address there will be up to
16 additional useless page faults, which might be potentially slow (and at
least is not very efficient)

Fortunately this option is off by default and only there on i386.

But fix it by checking for kernel addresses and also stopping when there's
a page fault.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent bd4f490
History
Tip revision: b45c6e76bc2c72f6426c14bed64fdcbc9bf37cb0 authored by Andi Kleen on 08 January 2010, 22:42:52 UTC
kernel/signal.c: fix kernel information leak with print-fatal-signals=1
Tip revision: b45c6e7
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