Commit Graph

38 Commits

Author SHA1 Message Date
Lai Jiangshan
505f14f7b8 tomoyo: use DEFINE_SRCU() to define tomoyo_ss
DEFINE_STATIC_SRCU() defines srcu struct and do init at build time.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2013-03-18 23:53:00 +11:00
Al Viro
808d4e3cfd consitify do_mount() arguments
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-10-11 20:02:04 -04:00
Eric W. Biederman
d2b31ca644 userns: Teach security_path_chown to take kuids and kgids
Don't make the security modules deal with raw user space uid and
gids instead pass in a kuid_t and a kgid_t so that security modules
only have to deal with internal kernel uids and gids.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: James Morris <james.l.morris@oracle.com>
Cc: John Johansen <john.johansen@canonical.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2012-09-21 03:13:25 -07:00
Eric Paris
83d498569e SELinux: rename dentry_open to file_open
dentry_open takes a file, rename it to file_open

Signed-off-by: Eric Paris <eparis@redhat.com>
2012-04-09 12:22:50 -04:00
Al Viro
cdcf116d44 switch security_path_chmod() to struct path *
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-06 23:16:53 -05:00
Al Viro
04fc66e789 switch ->path_mknod() to umode_t
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:55:19 -05:00
Al Viro
4572befe24 switch ->path_mkdir() to umode_t
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:55:18 -05:00
Al Viro
910f4ecef3 switch security_path_chmod() to umode_t
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:55:13 -05:00
Tetsuo Handa
059d84dbb3 TOMOYO: Add socket operation restriction support.
This patch adds support for permission checks for PF_INET/PF_INET6/PF_UNIX
socket's bind()/listen()/connect()/send() operations.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2011-09-14 08:27:05 +10:00
Tetsuo Handa
0f2a55d5bb TOMOYO: Update kernel-doc.
Update comments for scripts/kernel-doc and fix some of errors reported by
scripts/checkpatch.pl .

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2011-07-14 17:50:03 +10:00
Tetsuo Handa
97fb35e413 TOMOYO: Enable conditional ACL.
Enable conditional ACL by passing object's pointers.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2011-07-11 11:05:34 +10:00
Tetsuo Handa
7986cf28bc TOMOYO: Fix build error with CONFIG_SECURITY_TOMOYO_OMIT_USERSPACE_LOADER=y .
I forgot to add #ifndef in commit 0e4ae0e0 "TOMOYO: Make several options
configurable.", resulting

  security/built-in.o: In function `tomoyo_bprm_set_creds':
  tomoyo.c:(.text+0x4698e): undefined reference to `tomoyo_load_policy'

error.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2011-06-30 18:48:37 +10:00
Tetsuo Handa
7c75964f43 TOMOYO: Cleanup part 1.
In order to synchronize with TOMOYO 1.8's syntax,

(1) Remove special handling for allow_read/write permission.
(2) Replace deny_rewrite/allow_rewrite permission with allow_append permission.
(3) Remove file_pattern keyword.
(4) Remove allow_read permission from exception policy.
(5) Allow creating domains in enforcing mode without calling supervisor.
(6) Add permission check for opening directory for reading.
(7) Add permission check for stat() operation.
(8) Make "cat < /sys/kernel/security/tomoyo/self_domain" behave as if
    "cat /sys/kernel/security/tomoyo/self_domain".

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2011-06-29 09:31:19 +10:00
Tetsuo Handa
75093152a9 TOMOYO: Rename symbols.
Use shorter name in order to make it easier to fix 80 columns limit.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2010-08-02 15:34:33 +10:00
Tetsuo Handa
ea0d3ab239 LSM: Remove unused arguments from security_path_truncate().
When commit be6d3e56a6 "introduce new LSM hooks
where vfsmount is available." was proposed, regarding security_path_truncate(),
only "struct file *" argument (which AppArmor wanted to use) was removed.
But length and time_attrs arguments are not used by TOMOYO nor AppArmor.
Thus, let's remove these arguments.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: James Morris <jmorris@namei.org>
2010-08-02 15:33:40 +10:00
Tetsuo Handa
c3ef1500ec TOMOYO: Split files into some pieces.
security/tomoyo/common.c became too large to read.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2010-08-02 15:33:39 +10:00
Tetsuo Handa
2106ccd972 TOMOYO: Add mount restriction.
mount(2) has three string and one numeric parameters.
Split mount restriction code from security/tomoyo/file.c .

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2010-08-02 15:33:37 +10:00
Tetsuo Handa
a1f9bb6a37 TOMOYO: Split file access control functions by type of parameters.
Check numeric parameters for operations that deal them
(e.g. chmod/chown/ioctl).

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2010-08-02 15:33:37 +10:00
Tetsuo Handa
cb0abe6a5b TOMOYO: Use structure for passing common arguments.
Use "struct tomoyo_request_info" instead of passing individual arguments.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2010-08-02 15:33:36 +10:00
James Morris
b4ccebdd37 Merge branch 'next' into for-linus 2010-03-01 09:36:31 +11:00
Tetsuo Handa
97d6931ead TOMOYO: Remove unneeded parameter.
tomoyo_path_perm() tomoyo_path2_perm() and tomoyo_check_rewrite_permission()
always receive tomoyo_domain(). We can move it from caller to callee.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2010-02-16 17:26:36 +11:00
Tetsuo Handa
7ef612331f TOMOYO: Use shorter names.
Use shorter name to reduce newlines needed for 80 columns limit.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2010-02-16 11:17:16 +11:00
Tetsuo Handa
ec8e6a4e06 TOMOYO: Add refcounter on domain structure.
Add refcounter to "struct tomoyo_domain_info" since garbage collector needs to
determine whether this struct is referred by "struct cred"->security or not.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2010-02-15 09:00:21 +11:00
Tetsuo Handa
76bb0895d0 TOMOYO: Merge headers.
Gather structures and constants scattered around security/tomoyo/ directory.
This is for preparation for adding garbage collector since garbage collector
needs to know structures and constants which TOMOYO uses.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2010-02-15 09:00:18 +11:00
Al Viro
6d125529c6 Fix ACC_MODE() for real
commit 5300990c03 had stepped on a rather
nasty mess: definitions of ACC_MODE used to be different.  Fixed the
resulting breakage, converting them to variant that takes O_... value;
all callers have that and it actually simplifies life (see tomoyo part
of changes).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-01-14 09:05:26 -05:00
Tetsuo Handa
fdb8ebb729 TOMOYO: Use RCU primitives for list operation
Replace list operation with RCU primitives and replace
down_read()/up_read() with srcu_read_lock()/srcu_read_unlock().

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2009-12-15 15:46:31 +11:00
James Morris
1ad1f10cd9 Merge branch 'master' into next 2009-12-09 19:01:03 +11:00
Tetsuo Handa
937bf6133b TOMOYO: Add rest of file operation restrictions.
LSM hooks for chmod()/chown()/chroot() are now ready.
This patch utilizes these hooks.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2009-12-08 14:58:05 +11:00
Eric W. Biederman
c656ae95d1 security/tomoyo: Remove now unnecessary handling of security_sysctl.
Now that sys_sysctl is an emulation on top of proc sys all sysctl
operations look like normal filesystem operations and we don't need
to use the special sysctl hook to authenticate them.

Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2009-11-20 09:37:51 -08:00
Tetsuo Handa
86b1bc68e2 sysctl security/tomoyo: Don't look at ctl_name
ctl_name field was removed. Always use procname field.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2009-11-12 02:05:05 -08:00
David Howells
ee18d64c1f KEYS: Add a keyctl to install a process's session keyring on its parent [try #6]
Add a keyctl to install a process's session keyring onto its parent.  This
replaces the parent's session keyring.  Because the COW credential code does
not permit one process to change another process's credentials directly, the
change is deferred until userspace next starts executing again.  Normally this
will be after a wait*() syscall.

To support this, three new security hooks have been provided:
cred_alloc_blank() to allocate unset security creds, cred_transfer() to fill in
the blank security creds and key_session_to_parent() - which asks the LSM if
the process may replace its parent's session keyring.

The replacement may only happen if the process has the same ownership details
as its parent, and the process has LINK permission on the session keyring, and
the session keyring is owned by the process, and the LSM permits it.

Note that this requires alteration to each architecture's notify_resume path.
This has been done for all arches barring blackfin, m68k* and xtensa, all of
which need assembly alteration to support TIF_NOTIFY_RESUME.  This allows the
replacement to be performed at the point the parent process resumes userspace
execution.

This allows the userspace AFS pioctl emulation to fully emulate newpag() and
the VIOCSETTOK and VIOCSETTOK2 pioctls, all of which require the ability to
alter the parent process's PAG membership.  However, since kAFS doesn't use
PAGs per se, but rather dumps the keys into the session keyring, the session
keyring of the parent must be replaced if, for example, VIOCSETTOK is passed
the newpag flag.

This can be tested with the following program:

	#include <stdio.h>
	#include <stdlib.h>
	#include <keyutils.h>

	#define KEYCTL_SESSION_TO_PARENT	18

	#define OSERROR(X, S) do { if ((long)(X) == -1) { perror(S); exit(1); } } while(0)

	int main(int argc, char **argv)
	{
		key_serial_t keyring, key;
		long ret;

		keyring = keyctl_join_session_keyring(argv[1]);
		OSERROR(keyring, "keyctl_join_session_keyring");

		key = add_key("user", "a", "b", 1, keyring);
		OSERROR(key, "add_key");

		ret = keyctl(KEYCTL_SESSION_TO_PARENT);
		OSERROR(ret, "KEYCTL_SESSION_TO_PARENT");

		return 0;
	}

Compiled and linked with -lkeyutils, you should see something like:

	[dhowells@andromeda ~]$ keyctl show
	Session Keyring
	       -3 --alswrv   4043  4043  keyring: _ses
	355907932 --alswrv   4043    -1   \_ keyring: _uid.4043
	[dhowells@andromeda ~]$ /tmp/newpag
	[dhowells@andromeda ~]$ keyctl show
	Session Keyring
	       -3 --alswrv   4043  4043  keyring: _ses
	1055658746 --alswrv   4043  4043   \_ user: a
	[dhowells@andromeda ~]$ /tmp/newpag hello
	[dhowells@andromeda ~]$ keyctl show
	Session Keyring
	       -3 --alswrv   4043  4043  keyring: hello
	340417692 --alswrv   4043  4043   \_ user: a

Where the test program creates a new session keyring, sticks a user key named
'a' into it and then installs it on its parent.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2009-09-02 21:29:22 +10:00
Tetsuo Handa
56f8c9bc41 TOMOYO: Remove next_domain from tomoyo_find_next_domain().
We can update bprm->cred->security inside tomoyo_find_next_domain().

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2009-06-19 18:48:18 +10:00
Tetsuo Handa
c3fa109a58 TOMOYO: Add description of lists and structures.
This patch adds some descriptions of lists and structures.
This patch contains no code changes.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2009-06-09 09:30:24 +10:00
Herton Ronaldo Krzesinski
b1338d199d tomoyo: add missing call to cap_bprm_set_creds
cap_bprm_set_creds() has to be called from security_bprm_set_creds().
TOMOYO forgot to call cap_bprm_set_creds() from tomoyo_bprm_set_creds()
and suid executables were not being working.

Make sure we call cap_bprm_set_creds() with TOMOYO, to set credentials
properly inside tomoyo_bprm_set_creds().

Signed-off-by: Herton Ronaldo Krzesinski <herton@mandriva.com.br>
Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2009-05-27 09:46:48 +10:00
Tetsuo Handa
39826a1e17 tomoyo: version bump to 2.2.0.
Signed-off-by: Kentaro Takeda <takedakn@nttdata.co.jp>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Toshiharu Harada <haradats@nttdata.co.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2009-04-14 09:15:02 +10:00
Tetsuo Handa
1581e7ddbd TOMOYO: Do not call tomoyo_realpath_init unless registered.
tomoyo_realpath_init() is unconditionally called by security_initcall().
But nobody will use realpath related functions if TOMOYO is not registered.

So, let tomoyo_init() call tomoyo_realpath_init().

This patch saves 4KB of memory allocation if TOMOYO is not registered.

Signed-off-by: Kentaro Takeda <takedakn@nttdata.co.jp>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Toshiharu Harada <haradats@nttdata.co.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2009-02-23 09:45:05 +11:00
Tetsuo Handa
35d50e60e8 tomoyo: fix sparse warning
Fix sparse warning.

$ make C=2 SUBDIRS=security/tomoyo CF="-D__cold__="
 CHECK   security/tomoyo/common.c
 CHECK   security/tomoyo/realpath.c
 CHECK   security/tomoyo/tomoyo.c
security/tomoyo/tomoyo.c:110:8: warning: symbol 'buf' shadows an earlier one
security/tomoyo/tomoyo.c💯7: originally declared here

Signed-off-by: Kentaro Takeda <takedakn@nttdata.co.jp>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Toshiharu Harada <haradats@nttdata.co.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2009-02-12 20:21:10 +11:00
Kentaro Takeda
f743324377 LSM adapter functions.
DAC's permissions and TOMOYO's permissions are not one-to-one mapping.

Regarding DAC, there are "read", "write", "execute" permissions.
Regarding TOMOYO, there are "allow_read", "allow_write", "allow_read/write",
"allow_execute", "allow_create", "allow_unlink", "allow_mkdir", "allow_rmdir",
"allow_mkfifo", "allow_mksock", "allow_mkblock", "allow_mkchar",
"allow_truncate", "allow_symlink", "allow_rewrite", "allow_link",
"allow_rename" permissions.

+----------------------------------+----------------------------------+
| requested operation              | required TOMOYO's permission     |
+----------------------------------+----------------------------------+
| sys_open(O_RDONLY)               | allow_read                       |
+----------------------------------+----------------------------------+
| sys_open(O_WRONLY)               | allow_write                      |
+----------------------------------+----------------------------------+
| sys_open(O_RDWR)                 | allow_read/write                 |
+----------------------------------+----------------------------------+
| open_exec() from do_execve()     | allow_execute                    |
+----------------------------------+----------------------------------+
| open_exec() from !do_execve()    | allow_read                       |
+----------------------------------+----------------------------------+
| sys_read()                       | (none)                           |
+----------------------------------+----------------------------------+
| sys_write()                      | (none)                           |
+----------------------------------+----------------------------------+
| sys_mmap()                       | (none)                           |
+----------------------------------+----------------------------------+
| sys_uselib()                     | allow_read                       |
+----------------------------------+----------------------------------+
| sys_open(O_CREAT)                | allow_create                     |
+----------------------------------+----------------------------------+
| sys_open(O_TRUNC)                | allow_truncate                   |
+----------------------------------+----------------------------------+
| sys_truncate()                   | allow_truncate                   |
+----------------------------------+----------------------------------+
| sys_ftruncate()                  | allow_truncate                   |
+----------------------------------+----------------------------------+
| sys_open() without O_APPEND      | allow_rewrite                    |
+----------------------------------+----------------------------------+
| setfl() without O_APPEND         | allow_rewrite                    |
+----------------------------------+----------------------------------+
| sys_sysctl() for writing         | allow_write                      |
+----------------------------------+----------------------------------+
| sys_sysctl() for reading         | allow_read                       |
+----------------------------------+----------------------------------+
| sys_unlink()                     | allow_unlink                     |
+----------------------------------+----------------------------------+
| sys_mknod(S_IFREG)               | allow_create                     |
+----------------------------------+----------------------------------+
| sys_mknod(0)                     | allow_create                     |
+----------------------------------+----------------------------------+
| sys_mknod(S_IFIFO)               | allow_mkfifo                     |
+----------------------------------+----------------------------------+
| sys_mknod(S_IFSOCK)              | allow_mksock                     |
+----------------------------------+----------------------------------+
| sys_bind(AF_UNIX)                | allow_mksock                     |
+----------------------------------+----------------------------------+
| sys_mknod(S_IFBLK)               | allow_mkblock                    |
+----------------------------------+----------------------------------+
| sys_mknod(S_IFCHR)               | allow_mkchar                     |
+----------------------------------+----------------------------------+
| sys_symlink()                    | allow_symlink                    |
+----------------------------------+----------------------------------+
| sys_mkdir()                      | allow_mkdir                      |
+----------------------------------+----------------------------------+
| sys_rmdir()                      | allow_rmdir                      |
+----------------------------------+----------------------------------+
| sys_link()                       | allow_link                       |
+----------------------------------+----------------------------------+
| sys_rename()                     | allow_rename                     |
+----------------------------------+----------------------------------+

TOMOYO requires "allow_execute" permission of a pathname passed to do_execve()
but does not require "allow_read" permission of that pathname.
Let's consider 3 patterns (statically linked, dynamically linked,
shell script). This description is to some degree simplified.

  $ cat hello.c
  #include <stdio.h>
  int main() {
          printf("Hello\n");
          return 0;
  }
  $ cat hello.sh
  #! /bin/sh
  echo "Hello"
  $ gcc -static -o hello-static hello.c
  $ gcc -o hello-dynamic hello.c
  $ chmod 755 hello.sh

Case 1 -- Executing hello-static from bash.

  (1) The bash process calls fork() and the child process requests
      do_execve("hello-static").

  (2) The kernel checks "allow_execute hello-static" from "bash" domain.

  (3) The kernel calculates "bash hello-static" as the domain to transit to.

  (4) The kernel overwrites the child process by "hello-static".

  (5) The child process transits to "bash hello-static" domain.

  (6) The "hello-static" starts and finishes.

Case 2 -- Executing hello-dynamic from bash.

  (1) The bash process calls fork() and the child process requests
      do_execve("hello-dynamic").

  (2) The kernel checks "allow_execute hello-dynamic" from "bash" domain.

  (3) The kernel calculates "bash hello-dynamic" as the domain to transit to.

  (4) The kernel checks "allow_read ld-linux.so" from "bash hello-dynamic"
      domain. I think permission to access ld-linux.so should be charged
      hello-dynamic program, for "hello-dynamic needs ld-linux.so" is not
      a fault of bash program.

  (5) The kernel overwrites the child process by "hello-dynamic".

  (6) The child process transits to "bash hello-dynamic" domain.

  (7) The "hello-dynamic" starts and finishes.

Case 3 -- Executing hello.sh from bash.

  (1) The bash process calls fork() and the child process requests
      do_execve("hello.sh").

  (2) The kernel checks "allow_execute hello.sh" from "bash" domain.

  (3) The kernel calculates "bash hello.sh" as the domain to transit to.

  (4) The kernel checks "allow_read /bin/sh" from "bash hello.sh" domain.
      I think permission to access /bin/sh should be charged hello.sh program,
      for "hello.sh needs /bin/sh" is not a fault of bash program.

  (5) The kernel overwrites the child process by "/bin/sh".

  (6) The child process transits to "bash hello.sh" domain.

  (7) The "/bin/sh" requests open("hello.sh").

  (8) The kernel checks "allow_read hello.sh" from  "bash hello.sh" domain.

  (9) The "/bin/sh" starts and finishes.

Whether a file is interpreted as a program or not depends on an application.
The kernel cannot know whether the file is interpreted as a program or not.
Thus, TOMOYO treats "hello-static" "hello-dynamic" "ld-linux.so" "hello.sh"
"/bin/sh" equally as merely files; no distinction between executable and
non-executable. Therefore, TOMOYO doesn't check DAC's execute permission.
TOMOYO checks "allow_read" permission instead.

Calling do_execve() is a bold gesture that an old program's instance (i.e.
current process) is ready to be overwritten by a new program and is ready to
transfer control to the new program. To split purview of programs, TOMOYO
requires "allow_execute" permission of the new program against the old
program's instance and performs domain transition. If do_execve() succeeds,
the old program is no longer responsible against the consequence of the new
program's behavior. Only the new program is responsible for all consequences.

But TOMOYO doesn't require "allow_read" permission of the new program.
If TOMOYO requires "allow_read" permission of the new program, TOMOYO will
allow an attacker (who hijacked the old program's instance) to open the new
program and steal data from the new program. Requiring "allow_read" permission
will widen purview of the old program.

Not requiring "allow_read" permission of the new program against the old
program's instance is my design for reducing purview of the old program.
To be able to know whether the current process is in do_execve() or not,
I want to add in_execve flag to "task_struct".

Signed-off-by: Kentaro Takeda <takedakn@nttdata.co.jp>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Toshiharu Harada <haradats@nttdata.co.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2009-02-12 15:15:05 +11:00