]> git.karo-electronics.de Git - linux-beck.git/commit
powerpc: Ensure random space between stack and mmaps
authorAnton Blanchard <anton@samba.org>
Sun, 22 Feb 2009 01:50:05 +0000 (01:50 +0000)
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>
Mon, 23 Feb 2009 04:53:21 +0000 (15:53 +1100)
commita5adc91a4b44b5d1706b9d906cc14fe4f312afe9
treef0f5053b44b53fea4065bd05aeb9f0a53090d9dd
parent912f9ee21c836081e3c96dfe61025841ebeb95da
powerpc: Ensure random space between stack and mmaps

get_random_int() returns the same value within a 1 jiffy interval. This means
that the mmap and stack regions will almost always end up the same distance
apart, making a relative offset based attack possible.

To fix this, shift the randomness we use for the mmap region by 1 bit.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
arch/powerpc/mm/mmap.c