diff options
| author | Eric Paris <eparis@redhat.com> | 2007-06-28 15:55:21 -0400 |
|---|---|---|
| committer | James Morris <jmorris@namei.org> | 2007-07-11 22:52:29 -0400 |
| commit | ed0321895182ffb6ecf210e066d87911b270d587 (patch) | |
| tree | 832bb54666f73b06e55322df40f915c5e9ef64d7 /security/dummy.c | |
| parent | 13bddc2e9d591e31bf20020dc19ea6ca85de420e (diff) | |
security: Protection for exploiting null dereference using mmap
Add a new security check on mmap operations to see if the user is attempting
to mmap to low area of the address space. The amount of space protected is
indicated by the new proc tunable /proc/sys/vm/mmap_min_addr and defaults to
0, preserving existing behavior.
This patch uses a new SELinux security class "memprotect." Policy already
contains a number of allow rules like a_t self:process * (unconfined_t being
one of them) which mean that putting this check in the process class (its
best current fit) would make it useless as all user processes, which we also
want to protect against, would be allowed. By taking the memprotect name of
the new class it will also make it possible for us to move some of the other
memory protect permissions out of 'process' and into the new class next time
we bump the policy version number (which I also think is a good future idea)
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security/dummy.c')
| -rw-r--r-- | security/dummy.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/security/dummy.c b/security/dummy.c index 8ffd76405b5..d6a112ce297 100644 --- a/security/dummy.c +++ b/security/dummy.c @@ -420,8 +420,12 @@ static int dummy_file_ioctl (struct file *file, unsigned int command, static int dummy_file_mmap (struct file *file, unsigned long reqprot, unsigned long prot, - unsigned long flags) + unsigned long flags, + unsigned long addr, + unsigned long addr_only) { + if (addr < mmap_min_addr) + return -EACCES; return 0; } |