[PATCH v4 01/16] bluetooth: Switch SMP to crypto_cipher_encrypt_one()

[Andy Lutomirski <luto@kernel.org>]

SMP does ECB crypto on stack buffers.  This is complicated and
fragile, and it will not work if the stack is virtually allocated.

Switch to the crypto_cipher interface, which is simpler and safer.

Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-bluetooth@vger.kernel.org
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: netdev@vger.kernel.org
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
 net/bluetooth/smp.c | 67 ++++++++++++++++++++++-------------------------------
 1 file changed, 28 insertions(+), 39 deletions(-)

diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index 50976a6481f3..4c1a16a96ae5 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -22,9 +22,9 @@
 
 #include <linux/debugfs.h>
 #include <linux/scatterlist.h>
+#include <linux/crypto.h>
 #include <crypto/b128ops.h>
 #include <crypto/hash.h>
-#include <crypto/skcipher.h>
 
 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/hci_core.h>
@@ -88,7 +88,7 @@ struct smp_dev {
 	u8			min_key_size;
 	u8			max_key_size;
 
-	struct crypto_skcipher	*tfm_aes;
+	struct crypto_cipher	*tfm_aes;
 	struct crypto_shash	*tfm_cmac;
 };
 
@@ -127,7 +127,7 @@ struct smp_chan {
 	u8			dhkey[32];
 	u8			mackey[16];
 
-	struct crypto_skcipher	*tfm_aes;
+	struct crypto_cipher	*tfm_aes;
 	struct crypto_shash	*tfm_cmac;
 };
 
@@ -361,10 +361,8 @@ static int smp_h6(struct crypto_shash *tfm_cmac, const u8 w[16],
  * s1 and ah.
  */
 
-static int smp_e(struct crypto_skcipher *tfm, const u8 *k, u8 *r)
+static int smp_e(struct crypto_cipher *tfm, const u8 *k, u8 *r)
 {
-	SKCIPHER_REQUEST_ON_STACK(req, tfm);
-	struct scatterlist sg;
 	uint8_t tmp[16], data[16];
 	int err;
 
@@ -378,7 +376,7 @@ static int smp_e(struct crypto_skcipher *tfm, const u8 *k, u8 *r)
 	/* The most significant octet of key corresponds to k[0] */
 	swap_buf(k, tmp, 16);
 
-	err = crypto_skcipher_setkey(tfm, tmp, 16);
+	err = crypto_cipher_setkey(tfm, tmp, 16);
 	if (err) {
 		BT_ERR("cipher setkey failed: %d", err);
 		return err;
@@ -387,16 +385,7 @@ static int smp_e(struct crypto_skcipher *tfm, const u8 *k, u8 *r)
 	/* Most significant octet of plaintextData corresponds to data[0] */
 	swap_buf(r, data, 16);
 
-	sg_init_one(&sg, data, 16);
-
-	skcipher_request_set_tfm(req, tfm);
-	skcipher_request_set_callback(req, 0, NULL, NULL);
-	skcipher_request_set_crypt(req, &sg, &sg, 16, NULL);
-
-	err = crypto_skcipher_encrypt(req);
-	skcipher_request_zero(req);
-	if (err)
-		BT_ERR("Encrypt data error %d", err);
+	crypto_cipher_encrypt_one(tfm, data, data);
 
 	/* Most significant octet of encryptedData corresponds to data[0] */
 	swap_buf(data, r, 16);
@@ -406,7 +395,7 @@ static int smp_e(struct crypto_skcipher *tfm, const u8 *k, u8 *r)
 	return err;
 }
 
-static int smp_c1(struct crypto_skcipher *tfm_aes, const u8 k[16],
+static int smp_c1(struct crypto_cipher *tfm_aes, const u8 k[16],
 		  const u8 r[16], const u8 preq[7], const u8 pres[7], u8 _iat,
 		  const bdaddr_t *ia, u8 _rat, const bdaddr_t *ra, u8 res[16])
 {
@@ -455,7 +444,7 @@ static int smp_c1(struct crypto_skcipher *tfm_aes, const u8 k[16],
 	return err;
 }
 
-static int smp_s1(struct crypto_skcipher *tfm_aes, const u8 k[16],
+static int smp_s1(struct crypto_cipher *tfm_aes, const u8 k[16],
 		  const u8 r1[16], const u8 r2[16], u8 _r[16])
 {
 	int err;
@@ -471,7 +460,7 @@ static int smp_s1(struct crypto_skcipher *tfm_aes, const u8 k[16],
 	return err;
 }
 
-static int smp_ah(struct crypto_skcipher *tfm, const u8 irk[16],
+static int smp_ah(struct crypto_cipher *tfm, const u8 irk[16],
 		  const u8 r[3], u8 res[3])
 {
 	u8 _res[16];
@@ -759,7 +748,7 @@ static void smp_chan_destroy(struct l2cap_conn *conn)
 	kzfree(smp->slave_csrk);
 	kzfree(smp->link_key);
 
-	crypto_free_skcipher(smp->tfm_aes);
+	crypto_free_cipher(smp->tfm_aes);
 	crypto_free_shash(smp->tfm_cmac);
 
 	/* Ensure that we don't leave any debug key around if debug key
@@ -1359,9 +1348,9 @@ static struct smp_chan *smp_chan_create(struct l2cap_conn *conn)
 	if (!smp)
 		return NULL;
 
-	smp->tfm_aes = crypto_alloc_skcipher("ecb(aes)", 0, CRYPTO_ALG_ASYNC);
+	smp->tfm_aes = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
 	if (IS_ERR(smp->tfm_aes)) {
-		BT_ERR("Unable to create ECB crypto context");
+		BT_ERR("Unable to create AES crypto context");
 		kzfree(smp);
 		return NULL;
 	}
@@ -1369,7 +1358,7 @@ static struct smp_chan *smp_chan_create(struct l2cap_conn *conn)
 	smp->tfm_cmac = crypto_alloc_shash("cmac(aes)", 0, 0);
 	if (IS_ERR(smp->tfm_cmac)) {
 		BT_ERR("Unable to create CMAC crypto context");
-		crypto_free_skcipher(smp->tfm_aes);
+		crypto_free_cipher(smp->tfm_aes);
 		kzfree(smp);
 		return NULL;
 	}
@@ -3120,7 +3109,7 @@ static struct l2cap_chan *smp_add_cid(struct hci_dev *hdev, u16 cid)
 {
 	struct l2cap_chan *chan;
 	struct smp_dev *smp;
-	struct crypto_skcipher *tfm_aes;
+	struct crypto_cipher *tfm_aes;
 	struct crypto_shash *tfm_cmac;
 
 	if (cid == L2CAP_CID_SMP_BREDR) {
@@ -3132,9 +3121,9 @@ static struct l2cap_chan *smp_add_cid(struct hci_dev *hdev, u16 cid)
 	if (!smp)
 		return ERR_PTR(-ENOMEM);
 
-	tfm_aes = crypto_alloc_skcipher("ecb(aes)", 0, CRYPTO_ALG_ASYNC);
+	tfm_aes = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
 	if (IS_ERR(tfm_aes)) {
-		BT_ERR("Unable to create ECB crypto context");
+		BT_ERR("Unable to create AES crypto context");
 		kzfree(smp);
 		return ERR_CAST(tfm_aes);
 	}
@@ -3142,7 +3131,7 @@ static struct l2cap_chan *smp_add_cid(struct hci_dev *hdev, u16 cid)
 	tfm_cmac = crypto_alloc_shash("cmac(aes)", 0, 0);
 	if (IS_ERR(tfm_cmac)) {
 		BT_ERR("Unable to create CMAC crypto context");
-		crypto_free_skcipher(tfm_aes);
+		crypto_free_cipher(tfm_aes);
 		kzfree(smp);
 		return ERR_CAST(tfm_cmac);
 	}
@@ -3156,7 +3145,7 @@ create_chan:
 	chan = l2cap_chan_create();
 	if (!chan) {
 		if (smp) {
-			crypto_free_skcipher(smp->tfm_aes);
+			crypto_free_cipher(smp->tfm_aes);
 			crypto_free_shash(smp->tfm_cmac);
 			kzfree(smp);
 		}
@@ -3203,7 +3192,7 @@ static void smp_del_chan(struct l2cap_chan *chan)
 	smp = chan->data;
 	if (smp) {
 		chan->data = NULL;
-		crypto_free_skcipher(smp->tfm_aes);
+		crypto_free_cipher(smp->tfm_aes);
 		crypto_free_shash(smp->tfm_cmac);
 		kzfree(smp);
 	}
@@ -3440,7 +3429,7 @@ void smp_unregister(struct hci_dev *hdev)
 
 #if IS_ENABLED(CONFIG_BT_SELFTEST_SMP)
 
-static int __init test_ah(struct crypto_skcipher *tfm_aes)
+static int __init test_ah(struct crypto_cipher *tfm_aes)
 {
 	const u8 irk[16] = {
 			0x9b, 0x7d, 0x39, 0x0a, 0xa6, 0x10, 0x10, 0x34,
@@ -3460,7 +3449,7 @@ static int __init test_ah(struct crypto_skcipher *tfm_aes)
 	return 0;
 }
 
-static int __init test_c1(struct crypto_skcipher *tfm_aes)
+static int __init test_c1(struct crypto_cipher *tfm_aes)
 {
 	const u8 k[16] = {
 			0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
@@ -3490,7 +3479,7 @@ static int __init test_c1(struct crypto_skcipher *tfm_aes)
 	return 0;
 }
 
-static int __init test_s1(struct crypto_skcipher *tfm_aes)
+static int __init test_s1(struct crypto_cipher *tfm_aes)
 {
 	const u8 k[16] = {
 			0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
@@ -3686,7 +3675,7 @@ static const struct file_operations test_smp_fops = {
 	.llseek		= default_llseek,
 };
 
-static int __init run_selftests(struct crypto_skcipher *tfm_aes,
+static int __init run_selftests(struct crypto_cipher *tfm_aes,
 				struct crypto_shash *tfm_cmac)
 {
 	ktime_t calltime, delta, rettime;
@@ -3764,27 +3753,27 @@ done:
 
 int __init bt_selftest_smp(void)
 {
-	struct crypto_skcipher *tfm_aes;
+	struct crypto_cipher *tfm_aes;
 	struct crypto_shash *tfm_cmac;
 	int err;
 
-	tfm_aes = crypto_alloc_skcipher("ecb(aes)", 0, CRYPTO_ALG_ASYNC);
+	tfm_aes = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
 	if (IS_ERR(tfm_aes)) {
-		BT_ERR("Unable to create ECB crypto context");
+		BT_ERR("Unable to create AES crypto context");
 		return PTR_ERR(tfm_aes);
 	}
 
 	tfm_cmac = crypto_alloc_shash("cmac(aes)", 0, CRYPTO_ALG_ASYNC);
 	if (IS_ERR(tfm_cmac)) {
 		BT_ERR("Unable to create CMAC crypto context");
-		crypto_free_skcipher(tfm_aes);
+		crypto_free_cipher(tfm_aes);
 		return PTR_ERR(tfm_cmac);
 	}
 
 	err = run_selftests(tfm_aes, tfm_cmac);
 
 	crypto_free_shash(tfm_cmac);
-	crypto_free_skcipher(tfm_aes);
+	crypto_free_cipher(tfm_aes);
 
 	return err;
 }
-- 
2.5.5