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authorOleg Nesterov <oleg@redhat.com>2009-12-15 16:47:22 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-16 07:20:08 -0800
commit614c517d7c00af1b26ded20646b329397d6f51a1 (patch)
treeddd7a82b3479c9fabe141b4c82a1794650a82b4f
parentd51965037325e51f6cd68583413243c3573e47b0 (diff)
downloadop-kernel-dev-614c517d7c00af1b26ded20646b329397d6f51a1.zip
op-kernel-dev-614c517d7c00af1b26ded20646b329397d6f51a1.tar.gz
signals: SEND_SIG_NOINFO should be considered as SI_FROMUSER()
No changes in compiled code. The patch adds the new helper, si_fromuser() and changes check_kill_permission() to use this helper. The real effect of this patch is that from now we "officially" consider SEND_SIG_NOINFO signal as "from user-space" signals. This is already true if we look at the code which uses SEND_SIG_NOINFO, except __send_signal() has another opinion - see the next patch. The naming of these special SEND_SIG_XXX siginfo's is really bad imho. From __send_signal()'s pov they mean SEND_SIG_NOINFO from user SEND_SIG_PRIV from kernel SEND_SIG_FORCED no info Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Roland McGrath <roland@redhat.com> Reviewed-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/sched.h5
-rw-r--r--kernel/signal.c16
2 files changed, 13 insertions, 8 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index f4c1454..57b3516 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2102,11 +2102,6 @@ static inline int kill_cad_pid(int sig, int priv)
#define SEND_SIG_PRIV ((struct siginfo *) 1)
#define SEND_SIG_FORCED ((struct siginfo *) 2)
-static inline int is_si_special(const struct siginfo *info)
-{
- return info <= SEND_SIG_FORCED;
-}
-
/*
* True if we are on the alternate signal stack.
*/
diff --git a/kernel/signal.c b/kernel/signal.c
index 6b982f2..a0ba428 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -607,6 +607,17 @@ static int rm_from_queue(unsigned long mask, struct sigpending *s)
return 1;
}
+static inline int is_si_special(const struct siginfo *info)
+{
+ return info <= SEND_SIG_FORCED;
+}
+
+static inline bool si_fromuser(const struct siginfo *info)
+{
+ return info == SEND_SIG_NOINFO ||
+ (!is_si_special(info) && SI_FROMUSER(info));
+}
+
/*
* Bad permissions for sending the signal
* - the caller must hold at least the RCU read lock
@@ -621,7 +632,7 @@ static int check_kill_permission(int sig, struct siginfo *info,
if (!valid_signal(sig))
return -EINVAL;
- if (info != SEND_SIG_NOINFO && (is_si_special(info) || SI_FROMKERNEL(info)))
+ if (!si_fromuser(info))
return 0;
error = audit_signal_info(sig, t); /* Let audit system see the signal */
@@ -1186,8 +1197,7 @@ int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid,
goto out_unlock;
}
pcred = __task_cred(p);
- if ((info == SEND_SIG_NOINFO ||
- (!is_si_special(info) && SI_FROMUSER(info))) &&
+ if (si_fromuser(info) &&
euid != pcred->suid && euid != pcred->uid &&
uid != pcred->suid && uid != pcred->uid) {
ret = -EPERM;
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