Skip to main content

Browse the archive

https://github.com/torvalds/linux
23 October 2021, 00:29:24 UTC
Revision 4ae69e6b718589abe97c9625ccbb1e0bc95a8c0e authored by Kees Cook on 22 April 2010, 19:19:17 UTC, committed by James Morris on 14 May 2010, 09:03:15 UTC 
mmap_min_addr check CAP_SYS_RAWIO only for write
 
Redirecting directly to lsm, here's the patch discussed on lkml:
http://lkml.org/lkml/2010/4/22/219

The mmap_min_addr value is useful information for an admin to see without
being root ("is my system vulnerable to kernel NULL pointer attacks?") and
its setting is trivially easy for an attacker to determine by calling
mmap() in PAGE_SIZE increments starting at 0, so trying to keep it private
has no value.

Only require CAP_SYS_RAWIO if changing the value, not reading it.

Comment from Serge :

  Me, I like to write my passwords with light blue pen on dark blue
  paper, pasted on my window - if you're going to get my password, you're
  gonna get a headache.

Signed-off-by: Kees Cook <kees.cook@canonical.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
(cherry picked from commit 822cceec7248013821d655545ea45d1c6a9d15b3)
1 parent 6a251b0
History
Tip revision: 4ae69e6b718589abe97c9625ccbb1e0bc95a8c0e authored by Kees Cook on 22 April 2010, 19:19:17 UTC
mmap_min_addr check CAP_SYS_RAWIO only for write
Tip revision: 4ae69e6
File Mode Size
Documentation
arch
block
crypto
drivers
firmware
fs
include
init
ipc
kernel
lib
mm
net
samples
scripts
security
sound
tools
usr
virt
.gitignore -rw-r--r-- 930 bytes
.mailmap -rw-r--r-- 3.9 KB
COPYING -rw-r--r-- 18.3 KB
CREDITS -rw-r--r-- 91.8 KB
Kbuild -rw-r--r-- 2.4 KB
MAINTAINERS -rw-r--r-- 166.4 KB
Makefile -rw-r--r-- 51.9 KB
README -rw-r--r-- 17.0 KB
REPORTING-BUGS -rw-r--r-- 3.3 KB

README

back to top