From 5f46ce14bd432cf52bf91079270af164ca48f821 Mon Sep 17 00:00:00 2001 From: maximilian attems Date: Wed, 16 Apr 2008 19:36:36 +0200 Subject: [PATCH] security: enhance DEFAULT_MMAP_MIN_ADDR description Got burned by setting the proposed default of 65536 across all Debian archs. Thus proposing to be more specific on which archs you may set this. Also propose a value for arm and friends that doesn't break sshd. Reword to mention working archs ia64 and ppc64 too. Signed-off-by: maximilian attems Cc: Martin Michlmayr Cc: Gordon Farquharson Acked-by: Eric Paris Signed-off-by: James Morris --- security/Kconfig | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/security/Kconfig b/security/Kconfig index 5dfc206748cf..49b51f964897 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -113,10 +113,12 @@ config SECURITY_DEFAULT_MMAP_MIN_ADDR from userspace allocation. Keeping a user from writing to low pages can help reduce the impact of kernel NULL pointer bugs. - For most users with lots of address space a value of 65536 is - reasonable and should cause no problems. Programs which use vm86 - functionality would either need additional permissions from either - the LSM or the capabilities module or have this protection disabled. + For most ia64, ppc64 and x86 users with lots of address space + a value of 65536 is reasonable and should cause no problems. + On arm and other archs it should not be higher than 32768. + Programs which use vm86 functionality would either need additional + permissions from either the LSM or the capabilities module or have + this protection disabled. This value can be changed after boot using the /proc/sys/vm/mmap_min_addr tunable.