Merge branch 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

Pull security system updates from James Morris:

 - incorporate new socketpair() hook into LSM and wire up the SELinux
   and Smack modules. From David Herrmann:

     "The idea is to allow SO_PEERSEC to be called on AF_UNIX sockets
      created via socketpair(2), and return the same information as if
      you emulated socketpair(2) via a temporary listener socket.

      Right now SO_PEERSEC will return the unlabeled credentials for a
      socketpair, rather than the actual credentials of the creating
      process."

 - remove the unused security_settime LSM hook (Sargun Dhillon).

 - remove some stack allocated arrays from the keys code (Tycho
   Andersen)

* 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  dh key: get rid of stack allocated array for zeroes
  dh key: get rid of stack allocated array
  big key: get rid of stack array allocation
  smack: provide socketpair callback
  selinux: provide socketpair callback
  net: hook socketpair() into LSM
  security: add hook for socketpair()
  security: remove security_settime

include/linux/lsm_hooks.h

@@ -757,6 +757,11 @@
  *	@type contains the requested communications type.
  *	@protocol contains the requested protocol.
  *	@kern set to 1 if a kernel socket.
+ * @socket_socketpair:
+ *	Check permissions before creating a fresh pair of sockets.
+ *	@socka contains the first socket structure.
+ *	@sockb contains the second socket structure.
+ *	Return 0 if permission is granted and the connection was established.
  * @socket_bind:
  *	Check permission before socket protocol layer bind operation is
  *	performed and the socket @sock is bound to the address specified in the
@@ -1656,6 +1661,7 @@ union security_list_options {
 	int (*socket_create)(int family, int type, int protocol, int kern);
 	int (*socket_post_create)(struct socket *sock, int family, int type,
 					int protocol, int kern);
+	int (*socket_socketpair)(struct socket *socka, struct socket *sockb);
 	int (*socket_bind)(struct socket *sock, struct sockaddr *address,
 				int addrlen);
 	int (*socket_connect)(struct socket *sock, struct sockaddr *address,
@@ -1922,6 +1928,7 @@ struct security_hook_heads {
 	struct hlist_head unix_may_send;
 	struct hlist_head socket_create;
 	struct hlist_head socket_post_create;
+	struct hlist_head socket_socketpair;
 	struct hlist_head socket_bind;
 	struct hlist_head socket_connect;
 	struct hlist_head socket_listen;

include/linux/security.h

@@ -220,12 +220,6 @@ int security_quotactl(int cmds, int type, int id, struct super_block *sb);
 int security_quota_on(struct dentry *dentry);
 int security_syslog(int type);
 int security_settime64(const struct timespec64 *ts, const struct timezone *tz);
-static inline int security_settime(const struct timespec *ts, const struct timezone *tz)
-{
-	struct timespec64 ts64 = timespec_to_timespec64(*ts);
-
-	return security_settime64(&ts64, tz);
-}
 int security_vm_enough_memory_mm(struct mm_struct *mm, long pages);
 int security_bprm_set_creds(struct linux_binprm *bprm);
 int security_bprm_check(struct linux_binprm *bprm);
@@ -508,14 +502,6 @@ static inline int security_settime64(const struct timespec64 *ts,
 	return cap_settime(ts, tz);
 }
 
-static inline int security_settime(const struct timespec *ts,
-				   const struct timezone *tz)
-{
-	struct timespec64 ts64 = timespec_to_timespec64(*ts);
-
-	return cap_settime(&ts64, tz);
-}
-
 static inline int security_vm_enough_memory_mm(struct mm_struct *mm, long pages)
 {
 	return __vm_enough_memory(mm, pages, cap_vm_enough_memory(mm, pages));
@@ -1191,6 +1177,7 @@ int security_unix_may_send(struct socket *sock,  struct socket *other);
 int security_socket_create(int family, int type, int protocol, int kern);
 int security_socket_post_create(struct socket *sock, int family,
 				int type, int protocol, int kern);
+int security_socket_socketpair(struct socket *socka, struct socket *sockb);
 int security_socket_bind(struct socket *sock, struct sockaddr *address, int addrlen);
 int security_socket_connect(struct socket *sock, struct sockaddr *address, int addrlen);
 int security_socket_listen(struct socket *sock, int backlog);
@@ -1262,6 +1249,12 @@ static inline int security_socket_post_create(struct socket *sock,
 	return 0;
 }
 
+static inline int security_socket_socketpair(struct socket *socka,
+					     struct socket *sockb)
+{
+	return 0;
+}
+
 static inline int security_socket_bind(struct socket *sock,
 				       struct sockaddr *address,
 				       int addrlen)

net/socket.c

@@ -1445,6 +1445,13 @@ int __sys_socketpair(int family, int type, int protocol, int __user *usockvec)
 		goto out;
 	}
 
+	err = security_socket_socketpair(sock1, sock2);
+	if (unlikely(err)) {
+		sock_release(sock2);
+		sock_release(sock1);
+		goto out;
+	}
+
 	err = sock1->ops->socketpair(sock1, sock2);
 	if (unlikely(err < 0)) {
 		sock_release(sock2);

security/keys/big_key.c

@@ -22,6 +22,7 @@
 #include <keys/user-type.h>
 #include <keys/big_key-type.h>
 #include <crypto/aead.h>
+#include <crypto/gcm.h>
 
 struct big_key_buf {
 	unsigned int		nr_pages;
@@ -85,6 +86,7 @@ struct key_type key_type_big_key = {
  * Crypto names for big_key data authenticated encryption
  */
 static const char big_key_alg_name[] = "gcm(aes)";
+#define BIG_KEY_IV_SIZE		GCM_AES_IV_SIZE
 
 /*
  * Crypto algorithms for big_key data authenticated encryption
@@ -109,7 +111,7 @@ static int big_key_crypt(enum big_key_op op, struct big_key_buf *buf, size_t dat
 	 * an .update function, so there's no chance we'll wind up reusing the
 	 * key to encrypt updated data. Simply put: one key, one encryption.
 	 */
-	u8 zero_nonce[crypto_aead_ivsize(big_key_aead)];
+	u8 zero_nonce[BIG_KEY_IV_SIZE];
 
 	aead_req = aead_request_alloc(big_key_aead, GFP_KERNEL);
 	if (!aead_req)
@@ -425,6 +427,13 @@ static int __init big_key_init(void)
 		pr_err("Can't alloc crypto: %d\n", ret);
 		return ret;
 	}
+
+	if (unlikely(crypto_aead_ivsize(big_key_aead) != BIG_KEY_IV_SIZE)) {
+		WARN(1, "big key algorithm changed?");
+		ret = -EINVAL;
+		goto free_aead;
+	}
+
 	ret = crypto_aead_setauthsize(big_key_aead, ENC_AUTHTAG_SIZE);
 	if (ret < 0) {
 		pr_err("Can't set crypto auth tag len: %d\n", ret);

security/keys/dh.c

@@ -162,8 +162,8 @@ static int kdf_ctr(struct kdf_sdesc *sdesc, const u8 *src, unsigned int slen,
 			goto err;
 
 		if (zlen && h) {
-			u8 tmpbuffer[h];
+			u8 tmpbuffer[32];
-			size_t chunk = min_t(size_t, zlen, h);
+			size_t chunk = min_t(size_t, zlen, sizeof(tmpbuffer));
 			memset(tmpbuffer, 0, chunk);
 
 			do {
@@ -173,7 +173,7 @@ static int kdf_ctr(struct kdf_sdesc *sdesc, const u8 *src, unsigned int slen,
 					goto err;
 
 				zlen -= chunk;
-				chunk = min_t(size_t, zlen, h);
+				chunk = min_t(size_t, zlen, sizeof(tmpbuffer));
 			} while (zlen);
 		}
 
@@ -183,24 +183,13 @@ static int kdf_ctr(struct kdf_sdesc *sdesc, const u8 *src, unsigned int slen,
 				goto err;
 		}
 
-		if (dlen < h) {
+		err = crypto_shash_final(desc, dst);
-			u8 tmpbuffer[h];
+		if (err)
+			goto err;
 
-			err = crypto_shash_final(desc, tmpbuffer);
+		dlen -= h;
-			if (err)
+		dst += h;
-				goto err;
+		counter = cpu_to_be32(be32_to_cpu(counter) + 1);
-			memcpy(dst, tmpbuffer, dlen);
-			memzero_explicit(tmpbuffer, h);
-			return 0;
-		} else {
-			err = crypto_shash_final(desc, dst);
-			if (err)
-				goto err;
-
-			dlen -= h;
-			dst += h;
-			counter = cpu_to_be32(be32_to_cpu(counter) + 1);
-		}
 	}
 
 	return 0;
@@ -216,14 +205,16 @@ static int keyctl_dh_compute_kdf(struct kdf_sdesc *sdesc,
 {
 	uint8_t *outbuf = NULL;
 	int ret;
+	size_t outbuf_len = round_up(buflen,
+			             crypto_shash_digestsize(sdesc->shash.tfm));
 
-	outbuf = kmalloc(buflen, GFP_KERNEL);
+	outbuf = kmalloc(outbuf_len, GFP_KERNEL);
 	if (!outbuf) {
 		ret = -ENOMEM;
 		goto err;
 	}
 
-	ret = kdf_ctr(sdesc, kbuf, kbuflen, outbuf, buflen, lzero);
+	ret = kdf_ctr(sdesc, kbuf, kbuflen, outbuf, outbuf_len, lzero);
 	if (ret)
 		goto err;
 

security/security.c

@@ -1358,6 +1358,12 @@ int security_socket_post_create(struct socket *sock, int family,
 						protocol, kern);
 }
 
+int security_socket_socketpair(struct socket *socka, struct socket *sockb)
+{
+	return call_int_hook(socket_socketpair, 0, socka, sockb);
+}
+EXPORT_SYMBOL(security_socket_socketpair);
+
 int security_socket_bind(struct socket *sock, struct sockaddr *address, int addrlen)
 {
 	return call_int_hook(socket_bind, 0, sock, address, addrlen);

security/selinux/hooks.c

@@ -4580,6 +4580,18 @@ static int selinux_socket_post_create(struct socket *sock, int family,
 	return err;
 }
 
+static int selinux_socket_socketpair(struct socket *socka,
+				     struct socket *sockb)
+{
+	struct sk_security_struct *sksec_a = socka->sk->sk_security;
+	struct sk_security_struct *sksec_b = sockb->sk->sk_security;
+
+	sksec_a->peer_sid = sksec_b->sid;
+	sksec_b->peer_sid = sksec_a->sid;
+
+	return 0;
+}
+
 /* Range of port numbers used to automatically bind.
    Need to determine whether we should perform a name_bind
    permission check between the socket and the port number. */
@@ -7016,6 +7028,7 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
 
 	LSM_HOOK_INIT(socket_create, selinux_socket_create),
 	LSM_HOOK_INIT(socket_post_create, selinux_socket_post_create),
+	LSM_HOOK_INIT(socket_socketpair, selinux_socket_socketpair),
 	LSM_HOOK_INIT(socket_bind, selinux_socket_bind),
 	LSM_HOOK_INIT(socket_connect, selinux_socket_connect),
 	LSM_HOOK_INIT(socket_listen, selinux_socket_listen),

security/smack/smack_lsm.c

@@ -2842,6 +2842,27 @@ static int smack_socket_post_create(struct socket *sock, int family,
 	return smack_netlabel(sock->sk, SMACK_CIPSO_SOCKET);
 }
 
+/**
+ * smack_socket_socketpair - create socket pair
+ * @socka: one socket
+ * @sockb: another socket
+ *
+ * Cross reference the peer labels for SO_PEERSEC
+ *
+ * Returns 0 on success, and error code otherwise
+ */
+static int smack_socket_socketpair(struct socket *socka,
+		                   struct socket *sockb)
+{
+	struct socket_smack *asp = socka->sk->sk_security;
+	struct socket_smack *bsp = sockb->sk->sk_security;
+
+	asp->smk_packet = bsp->smk_out;
+	bsp->smk_packet = asp->smk_out;
+
+	return 0;
+}
+
 #ifdef SMACK_IPV6_PORT_LABELING
 /**
  * smack_socket_bind - record port binding information.
@@ -4724,6 +4745,7 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(unix_may_send, smack_unix_may_send),
 
 	LSM_HOOK_INIT(socket_post_create, smack_socket_post_create),
+	LSM_HOOK_INIT(socket_socketpair, smack_socket_socketpair),
 #ifdef SMACK_IPV6_PORT_LABELING
 	LSM_HOOK_INIT(socket_bind, smack_socket_bind),
 #endif