Re: [PATCH v5 01/32] bluetooth: Switch SMP to crypto_cipher_encrypt_one()

From: Andy Lutomirski
Date: Thu Jul 14 2016 - 15:11:15 EST

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On Mon, Jul 11, 2016 at 1:53 PM, Andy Lutomirski <luto@xxxxxxxxxx> wrote:
> 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.

Hi Dave-

It looks like we're delaying virtually mapped stacks to 4.9. That
means that there's time for this to go in through net-next. Could you
queue it up?

--Andy

>
> Cc: Marcel Holtmann <marcel@xxxxxxxxxxxx>
> Cc: Gustavo Padovan <gustavo@xxxxxxxxxxx>
> Cc: Johan Hedberg <johan.hedberg@xxxxxxxxx>
> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> Cc: linux-bluetooth@xxxxxxxxxxxxxxx
> Cc: netdev@xxxxxxxxxxxxxxx
> Acked-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> Acked-and-tested-by: Johan Hedberg <johan.hedberg@xxxxxxxxx>
> Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
> ---
> 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;
> }
> --
> 2.7.4
>

--
Andy Lutomirski
AMA Capital Management, LLC

Next message: Andy Lutomirski: "[PATCH 0/4] Virtually mapped stack prep for -mm"
Previous message: W. Trevor King: "Re: [PATCH 2/5] kernel: add a helper to get an owning user namespace for a namespace"
In reply to: Andy Lutomirski: "[PATCH v5 01/32] bluetooth: Switch SMP to crypto_cipher_encrypt_one()"
Next in thread: Marcel Holtmann: "Re: [PATCH v5 01/32] bluetooth: Switch SMP to crypto_cipher_encrypt_one()"
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