(patch 1/3) lsm: add control over /proc/ visibility

Serge Hallyn
2004-10-06T19:14:21Z

Attached is a patch which introduces a new LSM hook,
security_task_lookup. This hook allows an LSM to mediate visibility of
/proc/<pid> on a per-pid level. The bsdjail lsm which will be sent
next is a user of this hook.

Please apply.

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>

diff -Nrup linux-2.6.9-rc3-bk6/fs/proc/base.c
linux-2.6.9-rc3-bk6-jail/fs/proc/base.c
--- linux-2.6.9-rc3-bk6/fs/proc/base.c 2004-10-06 10:07:55.000000000
-0500
+++ linux-2.6.9-rc3-bk6-jail/fs/proc/base.c 2004-10-06
10:51:04.000000000 -0500
@@ -1683,6 +1683,8 @@ static int get_tgid_list(int index, unsi
int tgid = p->pid;
if (!pid_alive(p))
continue;
+ if (security_task_lookup(p))
+ continue;
if (--index >= 0)
continue;
tgids[nr_tgids] = tgid;
diff -Nrup linux-2.6.9-rc3-bk6/include/linux/security.h
linux-2.6.9-rc3-bk6-jail/include/linux/security.h
--- linux-2.6.9-rc3-bk6/include/linux/security.h 2004-08-14
00:37:30.000000000 -0500
+++ linux-2.6.9-rc3-bk6-jail/include/linux/security.h 2004-10-06
10:51:04.000000000 -0500
@@ -627,6 +627,11 @@ struct swap_info_struct;
* Set the security attributes in @p->security for a kernel thread
that
* is being reparented to the init task.
* @p contains the task_struct for the kernel thread.
+ * @task_lookup:
+ * Check permission to see the /proc/<pid> entry for process @p.
+ * @p contains the task_struct for task <pid> which is being looked
+ * up under /proc
+ * return 0 if permission is granted.
* @task_to_inode:
* Set the security attributes for an inode based on an associated
task's
* security attributes, e.g. for /proc/pid inodes.
@@ -1152,6 +1157,7 @@ struct security_operations {
unsigned long arg3, unsigned long arg4,
unsigned long arg5);
void (*task_reparent_to_init) (struct task_struct * p);
+ int (*task_lookup)(struct task_struct *p);
void (*task_to_inode)(struct task_struct *p, struct inode *inode);

int (*ipc_permission) (struct kern_ipc_perm * ipcp, short flag);
@@ -1751,6 +1757,11 @@ static inline void security_task_reparen
security_ops->task_reparent_to_init (p);
}

+static inline int security_task_lookup(struct task_struct *p)
+{
+ return security_ops->task_lookup(p);
+}
+
static inline void security_task_to_inode(struct task_struct *p, struct
inode *inode)
{
security_ops->task_to_inode(p, inode);
@@ -2386,6 +2397,11 @@ static inline void security_task_reparen
cap_task_reparent_to_init (p);
}

+static inline int security_task_lookup(struct task_struct *p)
+{
+ return 0;
+}
+
static inline void security_task_to_inode(struct task_struct *p, struct
inode *inode)
{ }

diff -Nrup linux-2.6.9-rc3-bk6/security/dummy.c
linux-2.6.9-rc3-bk6-jail/security/dummy.c
--- linux-2.6.9-rc3-bk6/security/dummy.c 2004-10-06 10:11:29.000000000
-0500
+++ linux-2.6.9-rc3-bk6-jail/security/dummy.c 2004-10-06
10:51:04.000000000 -0500
@@ -616,6 +616,11 @@ static void dummy_task_reparent_to_init
return;
}

+static int dummy_task_lookup(struct task_struct *p)
+{
+ return 0;
+}
+
static void dummy_task_to_inode(struct task_struct *p, struct inode
*inode)
{ }

@@ -978,6 +983,7 @@ void security_fixup_ops (struct security
set_to_dummy_if_null(ops, task_kill);
set_to_dummy_if_null(ops, task_prctl);
set_to_dummy_if_null(ops, task_reparent_to_init);
+ set_to_dummy_if_null(ops, task_lookup);
set_to_dummy_if_null(ops, task_to_inode);
set_to_dummy_if_null(ops, ipc_permission);
set_to_dummy_if_null(ops, msg_msg_alloc_security);