[PATCH 8/9] Task Watchers v2: Register process keyrings task watcher

From: Matt Helsley
Date: Thu Nov 02 2006 - 23:30:53 EST

Make the keyring code use a task watcher to initialize and free per-task data.

NOTE:
We can't make copy_thread_group_keys() in copy_signal() a task watcher because it needs the task's signal field (struct signal_struct).

Signed-off-by: Matt Helsley <matthltc@xxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
---
include/linux/key.h | 8 --------
kernel/exit.c | 2 --
kernel/fork.c | 6 +-----
kernel/sys.c | 8 --------
security/keys/process_keys.c | 19 ++++++++++++-------
5 files changed, 13 insertions(+), 30 deletions(-)

Benchmark results:
System: 4 1.7GHz ppc64 (Power 4+) processors, 30968600MB RAM, 2.6.19-rc2-mm2 kernel

Clone Number of Children Cloned
5000 7500 10000 12500 15000 17500
---------------------------------------------------------------------------------------
Mean 17746.8 17923.4 18079.1 18128.9 18182.7 18140.9
Dev 305.931 297.937 287.602 289.916 290.541 278.494
Err (%) 1.72387 1.66228 1.5908 1.5992 1.59789 1.53517

Fork Number of Children Forked
5000 7500 10000 12500 15000 17500
---------------------------------------------------------------------------------------
Mean 17678.6 17872.6 17975.1 18072.5 18166.1 18167.7
Dev 311.175 279.804 293.091 296.378 293.13 292.623
Err (%) 1.76017 1.56555 1.63054 1.63993 1.61361 1.61068

Kernbench:
Elapsed: 124.357s User: 439.753s System: 46.582s CPU: 390.6%
439.90user 46.56system 2:04.09elapsed 392%CPU (0avgtext+0avgdata 0maxresident)k
439.71user 46.48system 2:04.23elapsed 391%CPU (0avgtext+0avgdata 0maxresident)k
439.82user 46.71system 2:04.77elapsed 389%CPU (0avgtext+0avgdata 0maxresident)k
439.67user 46.53system 2:04.31elapsed 391%CPU (0avgtext+0avgdata 0maxresident)k
439.80user 46.55system 2:04.10elapsed 391%CPU (0avgtext+0avgdata 0maxresident)k
439.76user 46.54system 2:04.11elapsed 391%CPU (0avgtext+0avgdata 0maxresident)k
439.85user 46.79system 2:04.17elapsed 391%CPU (0avgtext+0avgdata 0maxresident)k
439.65user 46.50system 2:04.63elapsed 390%CPU (0avgtext+0avgdata 0maxresident)k
439.57user 46.55system 2:04.62elapsed 390%CPU (0avgtext+0avgdata 0maxresident)k
439.80user 46.61system 2:04.54elapsed 390%CPU (0avgtext+0avgdata 0maxresident)k

Index: linux-2.6.19-rc2-mm2/include/linux/key.h
===================================================================
--- linux-2.6.19-rc2-mm2.orig/include/linux/key.h
+++ linux-2.6.19-rc2-mm2/include/linux/key.h
@@ -335,18 +335,14 @@ extern void keyring_replace_payload(stru
*/
extern struct key root_user_keyring, root_session_keyring;
extern int alloc_uid_keyring(struct user_struct *user,
struct task_struct *ctx);
extern void switch_uid_keyring(struct user_struct *new_user);
-extern int copy_keys(unsigned long clone_flags, struct task_struct *tsk);
extern int copy_thread_group_keys(struct task_struct *tsk);
-extern void exit_keys(struct task_struct *tsk);
extern void exit_thread_group_keys(struct signal_struct *tg);
extern int suid_keys(struct task_struct *tsk);
extern int exec_keys(struct task_struct *tsk);
-extern void key_fsuid_changed(struct task_struct *tsk);
-extern void key_fsgid_changed(struct task_struct *tsk);
extern void key_init(void);

#define __install_session_keyring(tsk, keyring) \
({ \
struct key *old_session = tsk->signal->session_keyring; \
@@ -365,18 +361,14 @@ extern void key_init(void);
#define key_ref_to_ptr(k) ({ NULL; })
#define is_key_possessed(k) 0
#define alloc_uid_keyring(u,c) 0
#define switch_uid_keyring(u) do { } while(0)
#define __install_session_keyring(t, k) ({ NULL; })
-#define copy_keys(f,t) 0
#define copy_thread_group_keys(t) 0
-#define exit_keys(t) do { } while(0)
#define exit_thread_group_keys(tg) do { } while(0)
#define suid_keys(t) do { } while(0)
#define exec_keys(t) do { } while(0)
-#define key_fsuid_changed(t) do { } while(0)
-#define key_fsgid_changed(t) do { } while(0)
#define key_init() do { } while(0)

/* Initial keyrings */
extern struct key root_user_keyring;
extern struct key root_session_keyring;
Index: linux-2.6.19-rc2-mm2/kernel/fork.c
===================================================================
--- linux-2.6.19-rc2-mm2.orig/kernel/fork.c
+++ linux-2.6.19-rc2-mm2/kernel/fork.c
@@ -1070,14 +1070,12 @@ static struct task_struct *copy_process(
goto bad_fork_cleanup_fs;
if ((retval = copy_signal(clone_flags, p)))
goto bad_fork_cleanup_sighand;
if ((retval = copy_mm(clone_flags, p)))
goto bad_fork_cleanup_signal;
- if ((retval = copy_keys(clone_flags, p)))
- goto bad_fork_cleanup_mm;
if ((retval = copy_namespaces(clone_flags, p)))
- goto bad_fork_cleanup_keys;
+ goto bad_fork_cleanup_mm;
retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs);
if (retval)
goto bad_fork_cleanup_namespaces;

p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL;
@@ -1219,12 +1217,10 @@ static struct task_struct *copy_process(
proc_fork_connector(p);
return p;

bad_fork_cleanup_namespaces:
exit_task_namespaces(p);
-bad_fork_cleanup_keys:
- exit_keys(p);
bad_fork_cleanup_mm:
if (p->mm)
mmput(p->mm);
bad_fork_cleanup_signal:
cleanup_signal(p);
Index: linux-2.6.19-rc2-mm2/security/keys/process_keys.c
===================================================================
--- linux-2.6.19-rc2-mm2.orig/security/keys/process_keys.c
+++ linux-2.6.19-rc2-mm2/security/keys/process_keys.c
@@ -15,10 +15,11 @@
#include <linux/slab.h>
#include <linux/keyctl.h>
#include <linux/fs.h>
#include <linux/err.h>
#include <linux/mutex.h>
+#include <linux/task_watchers.h>
#include <asm/uaccess.h>
#include "internal.h"

/* session keyring create vs join semaphore */
static DEFINE_MUTEX(key_session_mutex);
@@ -276,11 +277,11 @@ int copy_thread_group_keys(struct task_s

/*****************************************************************************/
/*
* copy the keys for fork
*/
-int copy_keys(unsigned long clone_flags, struct task_struct *tsk)
+static int copy_keys(unsigned long clone_flags, struct task_struct *tsk)
{
key_check(tsk->thread_keyring);
key_check(tsk->request_key_auth);

/* no thread keyring yet */
@@ -290,10 +291,11 @@ int copy_keys(unsigned long clone_flags,
key_get(tsk->request_key_auth);

return 0;

} /* end copy_keys() */
+task_watcher_func(init, copy_keys);

/*****************************************************************************/
/*
* dispose of thread group keys upon thread group destruction
*/
@@ -306,16 +308,17 @@ void exit_thread_group_keys(struct signa

/*****************************************************************************/
/*
* dispose of per-thread keys upon thread exit
*/
-void exit_keys(struct task_struct *tsk)
+static int exit_keys(unsigned long exit_code, struct task_struct *tsk)
{
key_put(tsk->thread_keyring);
key_put(tsk->request_key_auth);
-
+ return 0;
} /* end exit_keys() */
+task_watcher_func(free, exit_keys);

/*****************************************************************************/
/*
* deal with execve()
*/
@@ -356,35 +359,37 @@ int suid_keys(struct task_struct *tsk)

/*****************************************************************************/
/*
* the filesystem user ID changed
*/
-void key_fsuid_changed(struct task_struct *tsk)
+static int key_fsuid_changed(unsigned long ignored, struct task_struct *tsk)
{
/* update the ownership of the thread keyring */
if (tsk->thread_keyring) {
down_write(&tsk->thread_keyring->sem);
tsk->thread_keyring->uid = tsk->fsuid;
up_write(&tsk->thread_keyring->sem);
}
-
+ return 0;
} /* end key_fsuid_changed() */
+task_watcher_func(uid, key_fsuid_changed);

/*****************************************************************************/
/*
* the filesystem group ID changed
*/
-void key_fsgid_changed(struct task_struct *tsk)
+static int key_fsgid_changed(unsigned long ignored, struct task_struct *tsk)
{
/* update the ownership of the thread keyring */
if (tsk->thread_keyring) {
down_write(&tsk->thread_keyring->sem);
tsk->thread_keyring->gid = tsk->fsgid;
up_write(&tsk->thread_keyring->sem);
}
-
+ return 0;
} /* end key_fsgid_changed() */
+task_watcher_func(gid, key_fsgid_changed);

/*****************************************************************************/
/*
* search the process keyrings for the first matching key
* - we use the supplied match function to see if the description (or other
Index: linux-2.6.19-rc2-mm2/kernel/exit.c
===================================================================
--- linux-2.6.19-rc2-mm2.orig/kernel/exit.c
+++ linux-2.6.19-rc2-mm2/kernel/exit.c
@@ -12,11 +12,10 @@
#include <linux/capability.h>
#include <linux/completion.h>
#include <linux/personality.h>
#include <linux/tty.h>
#include <linux/mnt_namespace.h>
-#include <linux/key.h>
#include <linux/security.h>
#include <linux/cpu.h>
#include <linux/acct.h>
#include <linux/tsacct_kern.h>
#include <linux/file.h>
@@ -919,11 +918,10 @@ fastcall NORET_TYPE void do_exit(long co
if (group_dead)
acct_process();
__exit_files(tsk);
__exit_fs(tsk);
exit_thread();
- exit_keys(tsk);

if (group_dead && tsk->signal->leader)
disassociate_ctty(1);

module_put(task_thread_info(tsk)->exec_domain->module);
Index: linux-2.6.19-rc2-mm2/kernel/sys.c
===================================================================
--- linux-2.6.19-rc2-mm2.orig/kernel/sys.c
+++ linux-2.6.19-rc2-mm2/kernel/sys.c
@@ -957,11 +957,10 @@ asmlinkage long sys_setregid(gid_t rgid,
(egid != (gid_t) -1 && egid != old_rgid))
current->sgid = new_egid;
current->fsgid = new_egid;
current->egid = new_egid;
current->gid = new_rgid;
- key_fsgid_changed(current);
proc_id_connector(current, PROC_EVENT_GID);
notify_task_watchers(WATCH_TASK_GID, 0, current);
return 0;
}

@@ -993,11 +992,10 @@ asmlinkage long sys_setgid(gid_t gid)
current->egid = current->fsgid = gid;
}
else
return -EPERM;

- key_fsgid_changed(current);
proc_id_connector(current, PROC_EVENT_GID);
notify_task_watchers(WATCH_TASK_GID, 0, current);
return 0;
}

@@ -1082,11 +1080,10 @@ asmlinkage long sys_setreuid(uid_t ruid,
if (ruid != (uid_t) -1 ||
(euid != (uid_t) -1 && euid != old_ruid))
current->suid = current->euid;
current->fsuid = current->euid;

- key_fsuid_changed(current);
proc_id_connector(current, PROC_EVENT_UID);
notify_task_watchers(WATCH_TASK_UID, 0, current);

return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
}
@@ -1130,11 +1127,10 @@ asmlinkage long sys_setuid(uid_t uid)
smp_wmb();
}
current->fsuid = current->euid = uid;
current->suid = new_suid;

- key_fsuid_changed(current);
proc_id_connector(current, PROC_EVENT_UID);
notify_task_watchers(WATCH_TASK_UID, 0, current);

return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
}
@@ -1179,11 +1175,10 @@ asmlinkage long sys_setresuid(uid_t ruid
}
current->fsuid = current->euid;
if (suid != (uid_t) -1)
current->suid = suid;

- key_fsuid_changed(current);
proc_id_connector(current, PROC_EVENT_UID);
notify_task_watchers(WATCH_TASK_UID, 0, current);

return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
}
@@ -1232,11 +1227,10 @@ asmlinkage long sys_setresgid(gid_t rgid
if (rgid != (gid_t) -1)
current->gid = rgid;
if (sgid != (gid_t) -1)
current->sgid = sgid;

- key_fsgid_changed(current);
proc_id_connector(current, PROC_EVENT_GID);
notify_task_watchers(WATCH_TASK_GID, 0, current);
return 0;
}

@@ -1274,11 +1268,10 @@ asmlinkage long sys_setfsuid(uid_t uid)
smp_wmb();
}
current->fsuid = uid;
}

- key_fsuid_changed(current);
proc_id_connector(current, PROC_EVENT_UID);
notify_task_watchers(WATCH_TASK_UID, 0, current);

security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);

@@ -1302,11 +1295,10 @@ asmlinkage long sys_setfsgid(gid_t gid)
if (gid != old_fsgid) {
current->mm->dumpable = suid_dumpable;
smp_wmb();
}
current->fsgid = gid;
- key_fsgid_changed(current);
proc_id_connector(current, PROC_EVENT_GID);
notify_task_watchers(WATCH_TASK_GID, 0, current);
}
return old_fsgid;
}

--
-
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