diff options
| author | Serge Hallyn <serge@hallyn.com> | 2008-02-29 15:14:57 +0000 |
|---|---|---|
| committer | Chris Wright <chrisw@sous-sol.org> | 2008-04-18 18:53:30 -0700 |
| commit | 44996dccd89ce86c7c38e37e0635d30c66279772 (patch) | |
| tree | 6c07faa687a71f06d0e1454c305543f5c059bb58 /security | |
| parent | d7d835ba45a0a2b30ed47887275e271e9ddddbdb (diff) | |
file capabilities: remove cap_task_kill()
upstream commit: aedb60a67c10a0861af179725d060765262ba0fb
The original justification for cap_task_kill() was as follows:
check_kill_permission() does appropriate uid equivalence checks.
However with file capabilities it becomes possible for an
unprivileged user to execute a file with file capabilities
resulting in a more privileged task with the same uid.
However now that cap_task_kill() always returns 0 (permission
granted) when p->uid==current->uid, the whole hook is worthless,
and only likely to create more subtle problems in the corner cases
where it might still be called but return -EPERM. Those cases
are basically when uids are different but euid/suid is equivalent
as per the check in check_kill_permission().
One example of a still-broken application is 'at' for non-root users.
This patch removes cap_task_kill().
Signed-off-by: Serge Hallyn <serge@hallyn.com>
Acked-by: Andrew G. Morgan <morgan@kernel.org>
Earlier-version-tested-by: Luiz Fernando N. Capitulino <lcapitulino@mandriva.com.br>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[chrisw@sous-sol.org: backport to 2.6.24.4]
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Diffstat (limited to 'security')
| -rw-r--r-- | security/capability.c | 1 | ||||
| -rw-r--r-- | security/commoncap.c | 39 |
2 files changed, 0 insertions, 40 deletions
diff --git a/security/capability.c b/security/capability.c index 9e99f36a8b5..2c6e06d18fa 100644 --- a/security/capability.c +++ b/security/capability.c @@ -40,7 +40,6 @@ static struct security_operations capability_ops = { .inode_need_killpriv = cap_inode_need_killpriv, .inode_killpriv = cap_inode_killpriv, - .task_kill = cap_task_kill, .task_setscheduler = cap_task_setscheduler, .task_setioprio = cap_task_setioprio, .task_setnice = cap_task_setnice, diff --git a/security/commoncap.c b/security/commoncap.c index e87422e766d..6e9065cbb7b 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -527,40 +527,6 @@ int cap_task_setnice (struct task_struct *p, int nice) return cap_safe_nice(p); } -int cap_task_kill(struct task_struct *p, struct siginfo *info, - int sig, u32 secid) -{ - if (info != SEND_SIG_NOINFO && (is_si_special(info) || SI_FROMKERNEL(info))) - return 0; - - /* - * Running a setuid root program raises your capabilities. - * Killing your own setuid root processes was previously - * allowed. - * We must preserve legacy signal behavior in this case. - */ - if (p->uid == current->uid) - return 0; - - /* sigcont is permitted within same session */ - if (sig == SIGCONT && (task_session_nr(current) == task_session_nr(p))) - return 0; - - if (secid) - /* - * Signal sent as a particular user. - * Capabilities are ignored. May be wrong, but it's the - * only thing we can do at the moment. - * Used only by usb drivers? - */ - return 0; - if (cap_issubset(p->cap_permitted, current->cap_permitted)) - return 0; - if (capable(CAP_KILL)) - return 0; - - return -EPERM; -} #else int cap_task_setscheduler (struct task_struct *p, int policy, struct sched_param *lp) @@ -575,11 +541,6 @@ int cap_task_setnice (struct task_struct *p, int nice) { return 0; } -int cap_task_kill(struct task_struct *p, struct siginfo *info, - int sig, u32 secid) -{ - return 0; -} #endif void cap_task_reparent_to_init (struct task_struct *p) |