From 618719c14729b2c9ef82cb462308671d11284a38 Mon Sep 17 00:00:00 2001
From: Dmitry Kasatkin <d.kasatkin@samsung.com>
Date: Fri, 14 Mar 2014 17:44:49 +0000
Subject: [PATCH 22/54] smack: fix key permission verification

For any keyring access type SMACK always used MAY_READWRITE access check.
It prevents reading the key with label "_", which should be allowed for anyone.

This patch changes default access check to MAY_READ and use MAY_READWRITE in only
appropriate cases.

Change-Id: I372968d614550d4c691301b2ef4b6478e76c62bf
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
---
 security/smack/smack_lsm.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 14f52be..16dcf7f 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3465,6 +3465,7 @@ static void smack_inet_csk_clone(struct sock *sk,
  * If you care about keys please have a look.
  */
 #ifdef CONFIG_KEYS
+#include "../keys/internal.h" /* HACK FOR THE BACKPORT */
 
 /**
  * smack_key_alloc - Set the key security blob
@@ -3511,6 +3512,7 @@ static int smack_key_permission(key_ref_t key_ref,
 	struct key *keyp;
 	struct smk_audit_info ad;
 	struct smack_known *tkp = smk_of_task(cred->security);
+	int request = 0;
 
 	keyp = key_ref_to_ptr(key_ref);
 	if (keyp == NULL)
@@ -3531,7 +3533,11 @@ static int smack_key_permission(key_ref_t key_ref,
 	ad.a.u.key_struct.key = keyp->serial;
 	ad.a.u.key_struct.key_desc = keyp->description;
 #endif
-	return smk_access(tkp, keyp->security, MAY_READWRITE, &ad);
+	if (perm & KEY_READ)
+		request = MAY_READ;
+	if (perm & (KEY_WRITE | KEY_LINK | KEY_SETATTR))
+		request = MAY_WRITE;
+	return smk_access(tkp, keyp->security, request, &ad);
 }
 #endif /* CONFIG_KEYS */
 
-- 
2.1.4