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 <max@stro.at> Cc: Martin Michlmayr <tbm@cyrius.com> Cc: Gordon Farquharson <gordonfarquharson@gmail.com> Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>

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 <max@stro.at> Cc: Martin Michlmayr <tbm@cyrius.com> Cc: Gordon Farquharson <gordonfarquharson@gmail.com> Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
maximilian attems · James Morris
1 parent 27cc2a6e57
Showing 1 changed file with 6 additions and 4 deletions Side-by-side Diff
security/Kconfig
@@ -113,10 +113,12 @@
 	  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.
...	...	@@ -113,10 +113,12 @@
113	113	from userspace allocation. Keeping a user from writing to low pages
114	114	can help reduce the impact of kernel NULL pointer bugs.
115	115
116		- For most users with lots of address space a value of 65536 is
117		- reasonable and should cause no problems. Programs which use vm86
118		- functionality would either need additional permissions from either
119		- the LSM or the capabilities module or have this protection disabled.
	116	+ For most ia64, ppc64 and x86 users with lots of address space
	117	+ a value of 65536 is reasonable and should cause no problems.
	118	+ On arm and other archs it should not be higher than 32768.
	119	+ Programs which use vm86 functionality would either need additional
	120	+ permissions from either the LSM or the capabilities module or have
	121	+ this protection disabled.
120	122
121	123	This value can be changed after boot using the
122	124	/proc/sys/vm/mmap_min_addr tunable.