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From: Casey Schaufler <casey.schaufler@intel.com>
To: kernel-hardening@lists.openwall.com,
	linux-kernel@vger.kernel.org,
	linux-security-module@vger.kernel.org, selinux@tycho.nsa.gov,
	casey.schaufler@intel.com, dave.hansen@intel.com,
	deneen.t.dock@intel.com, kristen@linux.intel.com,
	arjan@linux.intel.com
Subject: [PATCH v5 3/5] SELinux: Prepare for PTRACE_MODE_SCHED
Date: Wed, 26 Sep 2018 13:34:44 -0700	[thread overview]
Message-ID: <20180926203446.2004-4-casey.schaufler@intel.com> (raw)
In-Reply-To: <20180926203446.2004-1-casey.schaufler@intel.com>

From: Casey Schaufler <casey@schaufler-ca.com>

A ptrace access check with mode PTRACE_MODE_SCHED gets called
from process switching code. This precludes the use of audit or avc,
as the locking is incompatible. The only available check that
can be made without using avc is a comparison of the secids.
This is not very satisfactory as it will indicate possible
vulnerabilies much too aggressively.

Signed-off-by: Casey Schaufler <casey.schaufler@intel.com>
---
 security/selinux/hooks.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index ad9a9b8e9979..160239791007 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2267,6 +2267,8 @@ static int selinux_ptrace_access_check(struct task_struct *child,
 	u32 sid = current_sid();
 	u32 csid = task_sid(child);
 
+	if (mode & PTRACE_MODE_SCHED)
+		return sid == csid ? 0 : -EACCES;
 	if (mode & PTRACE_MODE_READ)
 		return avc_has_perm(&selinux_state,
 				    sid, csid, SECCLASS_FILE, FILE__READ, NULL);
-- 
2.17.1


WARNING: multiple messages have this Message-ID (diff)
From: casey.schaufler@intel.com (Casey Schaufler)
To: linux-security-module@vger.kernel.org
Subject: [PATCH v5 3/5] SELinux: Prepare for PTRACE_MODE_SCHED
Date: Wed, 26 Sep 2018 13:34:44 -0700	[thread overview]
Message-ID: <20180926203446.2004-4-casey.schaufler@intel.com> (raw)
In-Reply-To: <20180926203446.2004-1-casey.schaufler@intel.com>

From: Casey Schaufler <casey@schaufler-ca.com>

A ptrace access check with mode PTRACE_MODE_SCHED gets called
from process switching code. This precludes the use of audit or avc,
as the locking is incompatible. The only available check that
can be made without using avc is a comparison of the secids.
This is not very satisfactory as it will indicate possible
vulnerabilies much too aggressively.

Signed-off-by: Casey Schaufler <casey.schaufler@intel.com>
---
 security/selinux/hooks.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index ad9a9b8e9979..160239791007 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2267,6 +2267,8 @@ static int selinux_ptrace_access_check(struct task_struct *child,
 	u32 sid = current_sid();
 	u32 csid = task_sid(child);
 
+	if (mode & PTRACE_MODE_SCHED)
+		return sid == csid ? 0 : -EACCES;
 	if (mode & PTRACE_MODE_READ)
 		return avc_has_perm(&selinux_state,
 				    sid, csid, SECCLASS_FILE, FILE__READ, NULL);
-- 
2.17.1

  parent reply	other threads:[~2018-09-26 20:35 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-26 20:34 [PATCH v5 0/5] LSM: Support ptrace sidechannel access checks Casey Schaufler
2018-09-26 20:34 ` Casey Schaufler
2018-09-26 20:34 ` [PATCH v5 1/5] AppArmor: Prepare for PTRACE_MODE_SCHED Casey Schaufler
2018-09-26 20:34   ` Casey Schaufler
2018-09-26 21:16   ` Jann Horn
2018-09-26 21:16     ` Jann Horn
2018-09-26 21:18     ` Jann Horn
2018-09-26 21:18       ` Jann Horn
2018-09-26 22:47       ` Schaufler, Casey
2018-09-26 22:47         ` Schaufler, Casey
2018-09-26 20:34 ` [PATCH v5 2/5] Smack: " Casey Schaufler
2018-09-26 20:34   ` Casey Schaufler
2018-09-26 21:30   ` Jann Horn
2018-09-26 21:30     ` Jann Horn
2018-09-26 22:53     ` Schaufler, Casey
2018-09-26 22:53       ` Schaufler, Casey
2018-09-26 22:58       ` Jann Horn
2018-09-26 22:58         ` Jann Horn
2018-10-04  7:47         ` Jiri Kosina
2018-10-04 11:36           ` Jann Horn
2018-10-16 11:44             ` Jiri Kosina
2018-09-26 20:34 ` Casey Schaufler [this message]
2018-09-26 20:34   ` [PATCH v5 3/5] SELinux: " Casey Schaufler
2018-09-27  1:53   ` Stephen Smalley
2018-09-27 15:50   ` Stephen Smalley
2018-09-27 15:50     ` Stephen Smalley
2018-09-27 16:23     ` Schaufler, Casey
2018-09-27 16:23       ` Schaufler, Casey
2018-09-27 16:23       ` Schaufler, Casey
2018-09-26 20:34 ` [PATCH v5 4/5] Capability: Complete PTRACE_MODE_SCHED Casey Schaufler
2018-09-26 20:34   ` Casey Schaufler
2018-09-26 21:26   ` Jann Horn
2018-09-26 21:26     ` Jann Horn
2018-09-26 22:24     ` Schaufler, Casey
2018-09-26 22:24       ` Schaufler, Casey
2018-09-26 20:34 ` [PATCH v5 5/5] sidechannel: Linux Security Module for sidechannel Casey Schaufler
2018-09-26 20:34   ` Casey Schaufler
2018-09-27 21:45   ` James Morris
2018-09-27 21:45     ` James Morris
2018-09-27 22:39     ` Casey Schaufler
2018-09-27 22:39       ` Casey Schaufler
2018-09-27 22:47       ` James Morris
2018-09-27 22:47         ` James Morris
2018-09-27 23:19         ` Schaufler, Casey
2018-09-27 23:19           ` Schaufler, Casey
2018-09-27 23:19           ` Schaufler, Casey
2018-09-27 23:43           ` James Morris
2018-09-27 23:43             ` James Morris
2018-09-27 23:43             ` James Morris
2018-09-27 23:47             ` Jann Horn
2018-09-27 23:47               ` Jann Horn
2018-09-28 16:33               ` James Morris
2018-09-28 16:33                 ` James Morris
2018-09-28 17:40                 ` Schaufler, Casey
2018-09-28 17:40                   ` Schaufler, Casey

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