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.
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>
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index c47dd8c..8177e7d 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3511,6 +3511,7 @@
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 +3532,11 @@
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_NEED_READ)
+ request = MAY_READ;
+ if (perm & (KEY_NEED_WRITE | KEY_NEED_LINK | KEY_NEED_SETATTR))
+ request = MAY_WRITE;
+ return smk_access(tkp, keyp->security, request, &ad);
}
#endif /* CONFIG_KEYS */