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author | Serge Hallyn <serge@hallyn.com> | 2008-02-29 15:14:57 +0000 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-03-20 09:46:36 -0700 |
commit | aedb60a67c10a0861af179725d060765262ba0fb (patch) | |
tree | 4a4a316f9f7d1ab0bf4da2cdd5c802bfb05c947f /security/commoncap.c | |
parent | 457fb605834504af294916411be128a9b21fc3f6 (diff) | |
download | kernel_goldelico_gta04-aedb60a67c10a0861af179725d060765262ba0fb.zip kernel_goldelico_gta04-aedb60a67c10a0861af179725d060765262ba0fb.tar.gz kernel_goldelico_gta04-aedb60a67c10a0861af179725d060765262ba0fb.tar.bz2 |
file capabilities: remove cap_task_kill()
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>
Diffstat (limited to 'security/commoncap.c')
-rw-r--r-- | security/commoncap.c | 40 |
1 files changed, 0 insertions, 40 deletions
diff --git a/security/commoncap.c b/security/commoncap.c index bb0c095..06d5c94 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -540,41 +540,6 @@ 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; -} - /* * called from kernel/sys.c for prctl(PR_CABSET_DROP) * done without task_capability_lock() because it introduces @@ -605,11 +570,6 @@ 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) |