linux-kernel - [PATCH 7/7][v7] proc: Show SIG_DFL signals to init as "ignored" signals

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20090117203753.GH11825@us.ibm.com>
Date:	Sat, 17 Jan 2009 12:37:53 -0800
From:	Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com>
To:	oleg@...hat.com, ebiederm@...ssion.com, roland@...hat.com,
	bastian@...di.eu.org
Cc:	daniel@...ac.com, xemul@...nvz.org, containers@...ts.osdl.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 7/7][v7] proc: Show SIG_DFL signals to init as "ignored"
	signals


From: Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com>
Date: Sat, 17 Jan 2009 09:26:26 -0800
Subject: [PATCH 7/7][v7] proc: Show SIG_DFL signals to init as "ignored" signals

Init processes ignore SIG_DFL signals unless they are from an ancestor
namespace.  Ensure /proc/pid/status correcly reports these signals.

Values for "normal" /bin/bash from /proc/pid/status:

	SigIgn: 0000000000384004
	SigCgt: 000000004b813efb

	Signals 9, 16, 19 etc are neither ignored nor caught

/bin/bash as container-init, Status viewed from outside container:

	SigIgn: 0000000000384004
	SigCgt: 000000004b813efb

	(same as 'normal')

/bin/bash as container-init, Status viewed from inside container:

	SigIgn: ffffffffb47ec104
	SigCgt: 000000004b813efb

	All "uncaught" signals, including SIGKILL(9) SIGSTOP(19) are ignored.

Signed-off-by: Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com>
---
 fs/proc/array.c |   18 +++++++++++++++++-
 1 files changed, 17 insertions(+), 1 deletions(-)

diff --git a/fs/proc/array.c b/fs/proc/array.c
index 7e4877d..16e39db 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -228,15 +228,31 @@ static void render_sigset_t(struct seq_file *m, const char *header,
 	seq_printf(m, "\n");
 }
 
+static int is_unkillable(struct task_struct *p)
+{
+	if (!(p->signal->flags & SIGNAL_UNKILLABLE))
+		return 0;
+
+	/* If caller is an ancestor, we are not unkillable */
+	if (task_pid_nr_ns(current, task_active_pid_ns(p)) <= 0)
+		return 0;
+
+	return 1;
+}
+
 static void collect_sigign_sigcatch(struct task_struct *p, sigset_t *ign,
 				    sigset_t *catch)
 {
 	struct k_sigaction *k;
 	int i;
+	int unkillable;
+	
+	unkillable = is_unkillable(p);
 
 	k = p->sighand->action;
 	for (i = 1; i <= _NSIG; ++i, ++k) {
-		if (k->sa.sa_handler == SIG_IGN)
+		if (k->sa.sa_handler == SIG_IGN ||
+				(k->sa.sa_handler == SIG_DFL && unkillable))
 			sigaddset(ign, i);
 		else if (k->sa.sa_handler != SIG_DFL)
 			sigaddset(catch, i);
-- 
1.5.2.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/