Kconfig: enhance DEFAULT_MMAP_MIN_ADDR description
PATCH 1/1 Kconfig: 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.
--- security/Kconfig | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-)
security/Kconfig +3 -2
@@ -113,8 +113,9 @@ 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 + For most 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.
Signature · 1 line
1.5.5
Quoted 6 lines · maximilian attems
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.
I certainly don't have a problem with the patch.
Although I do have reports of ppc64 and ia64 working fine with 64k I don't see the need to clutter up the issue by listing all 3 arches I've seen it not break instead of your message just mentioning x86.
-Eric
maximilian attems
Acked-by Eric ParisGot 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.
security/Kconfig +6 -4
@@ -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.
James Morris
maintainerQuoted 7 lines · maximilian attems
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.
Quoted 6 lines
Reword to mention working archs ia64 and ppc64 too.
Signed-off-by maximilian attems <[email protected]>Cc Martin Michlmayr <[email protected]>Cc Gordon Farquharson <[email protected]>Acked-by Eric Paris <[email protected]>
Applied togit://git.kernel.org/pub/scm/linux/kernel/git/jmorris/selinux-2.6.git#for-akpm
Signature · 2 lines
James Morris <[email protected]>