diff options
author | Oleg Nesterov <oleg@tv-sign.ru> | 2008-04-30 00:52:42 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-30 08:29:34 -0700 |
commit | 3b5e9e53c6f31b5a5a0f5c43707503c62bdefa46 (patch) | |
tree | 1244b7cf2755c06a8a793149ce4717e4a1311218 | |
parent | 9e3bd6c3fb2334be171e69b432039cd18bce4458 (diff) | |
download | linux-3b5e9e53c6f31b5a5a0f5c43707503c62bdefa46.tar.bz2 |
signals: cleanup security_task_kill() usage/implementation
Every implementation of ->task_kill() does nothing when the signal comes from
the kernel. This is correct, but means that check_kill_permission() should
call security_task_kill() only for SI_FROMUSER() case, and we can remove the
same check from ->task_kill() implementations.
(sadly, check_kill_permission() is the last user of signal->session/__session
but we can't s/task_session_nr/task_session/ here).
NOTE: Eric W. Biederman pointed out cap_task_kill() should die, and I think
he is very right.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: David Quigley <dpquigl@tycho.nsa.gov>
Cc: Eric Paris <eparis@redhat.com>
Cc: Harald Welte <laforge@gnumonks.org>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | kernel/signal.c | 27 | ||||
-rw-r--r-- | security/selinux/hooks.c | 3 | ||||
-rw-r--r-- | security/smack/smack_lsm.c | 9 |
3 files changed, 14 insertions, 25 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index f9a52c721274..91d57f89f5a5 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -533,22 +533,23 @@ static int rm_from_queue(unsigned long mask, struct sigpending *s) static int check_kill_permission(int sig, struct siginfo *info, struct task_struct *t) { - int error = -EINVAL; + int error; + if (!valid_signal(sig)) - return error; + return -EINVAL; - if (info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info))) { - error = audit_signal_info(sig, t); /* Let audit system see the signal */ - if (error) - return error; - error = -EPERM; - if (((sig != SIGCONT) || - (task_session_nr(current) != task_session_nr(t))) - && (current->euid ^ t->suid) && (current->euid ^ t->uid) - && (current->uid ^ t->suid) && (current->uid ^ t->uid) - && !capable(CAP_KILL)) + if (info != SEND_SIG_NOINFO && (is_si_special(info) || SI_FROMKERNEL(info))) + return 0; + + error = audit_signal_info(sig, t); /* Let audit system see the signal */ + if (error) return error; - } + + if (((sig != SIGCONT) || (task_session_nr(current) != task_session_nr(t))) + && (current->euid ^ t->suid) && (current->euid ^ t->uid) + && (current->uid ^ t->suid) && (current->uid ^ t->uid) + && !capable(CAP_KILL)) + return -EPERM; return security_task_kill(t, info, sig, 0); } diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 85a220465a8f..1b50a6ebc55f 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3286,9 +3286,6 @@ static int selinux_task_kill(struct task_struct *p, struct siginfo *info, if (rc) return rc; - if (info != SEND_SIG_NOINFO && (is_si_special(info) || SI_FROMKERNEL(info))) - return 0; - if (!sig) perm = PROCESS__SIGNULL; /* null signal; existence test */ else diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index fe0ae1bf1650..b5c8f9237008 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -1131,15 +1131,6 @@ static int smack_task_kill(struct task_struct *p, struct siginfo *info, int sig, u32 secid) { /* - * Special cases where signals really ought to go through - * in spite of policy. Stephen Smalley suggests it may - * make sense to change the caller so that it doesn't - * bother with the LSM hook in these cases. - */ - if (info != SEND_SIG_NOINFO && - (is_si_special(info) || SI_FROMKERNEL(info))) - return 0; - /* * Sending a signal requires that the sender * can write the receiver. */ |