korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-27 06:04:23 +08:00
Code Issues Packages Projects Releases Wiki Activity

selinux: add a map permission check for mmap

Browse Source 
Add a map permission check on mmap so that we can distinguish memory mapped
access (since it has different implications for revocation). When a file
is opened and then read or written via syscalls like read(2)/write(2),
we revalidate access on each read/write operation via
selinux_file_permission() and therefore can revoke access if the
process context, the file context, or the policy changes in such a
manner that access is no longer allowed. When a file is opened and then
memory mapped via mmap(2) and then subsequently read or written directly
in memory, we presently have no way to revalidate or revoke access.
The purpose of a separate map permission check on mmap(2) is to permit
policy to prohibit memory mapping of specific files for which we need
to ensure that every access is revalidated, particularly useful for
scenarios where we expect the file to be relabeled at runtime in order
to reflect state changes (e.g. cross-domain solution, assured pipeline
without data copying).

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This commit is contained in:
Stephen Smalley 2017-05-05 09:14:48 -04:00 committed by Paul Moore
parent db59000ab7
commit 3ba4bf5f1e
2 changed files with 13 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
security/selinux/hooks.c
View File

@ -3557,6 +3557,18 @@ static int selinux_mmap_addr(unsigned long addr)
static int selinux_mmap_file(struct file *file, unsigned long reqprot,
unsigned long prot, unsigned long flags)
{
struct common_audit_data ad;
int rc;
if (file) {
ad.type = LSM_AUDIT_DATA_FILE;
ad.u.file = file;
rc = inode_has_perm(current_cred(), file_inode(file),
FILE__MAP, &ad);
if (rc)
return rc;
}
if (selinux_checkreqprot)
prot = reqprot;

2
security/selinux/include/classmap.h
View File

@ -1,7 +1,7 @@
#include <linux/capability.h>
#define COMMON_FILE_SOCK_PERMS "ioctl", "read", "write", "create", \
"getattr", "setattr", "lock", "relabelfrom", "relabelto", "append"
"getattr", "setattr", "lock", "relabelfrom", "relabelto", "append", "map"
#define COMMON_FILE_PERMS COMMON_FILE_SOCK_PERMS, "unlink", "link", \
"rename", "execute", "quotaon", "mounton", "audit_access", \