[PPP_MPPE]: Don't put InterimKey on the stack

Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 8 deletions

diff --git a/drivers/net/ppp_mppe.c b/drivers/net/ppp_mppe.c
index f79cf87a2bf..c0b6d19d145 100644
--- a/drivers/net/ppp_mppe.c
+++ b/drivers/net/ppp_mppe.c
@@ -136,7 +136,7 @@ struct ppp_mppe_state {
  * Key Derivation, from RFC 3078, RFC 3079.
  * Equivalent to Get_Key() for MS-CHAP as described in RFC 3079.
  */
-static void get_new_key_from_sha(struct ppp_mppe_state * state, unsigned char *InterimKey)
+static void get_new_key_from_sha(struct ppp_mppe_state * state)
 {
         struct hash_desc desc;
         struct scatterlist sg[4];
@@ -153,8 +153,6 @@ static void get_new_key_from_sha(struct ppp_mppe_state * state, unsigned char *I
         desc.flags = 0;
 
         crypto_hash_digest(&desc, sg, nbytes, state->sha1_digest);
-
-        memcpy(InterimKey, state->sha1_digest, state->keylen);
 }
 
 /*
@@ -163,21 +161,21 @@ static void get_new_key_from_sha(struct ppp_mppe_state * state, unsigned char *I
  */
 static void mppe_rekey(struct ppp_mppe_state * state, int initial_key)
 {
-        unsigned char InterimKey[MPPE_MAX_KEY_LEN];
         struct scatterlist sg_in[1], sg_out[1];
         struct blkcipher_desc desc = { .tfm = state->arc4 };
 
-        get_new_key_from_sha(state, InterimKey);
+        get_new_key_from_sha(state);
         if (!initial_key) {
-                crypto_blkcipher_setkey(state->arc4, InterimKey, state->keylen);
-                setup_sg(sg_in, InterimKey, state->keylen);
+                crypto_blkcipher_setkey(state->arc4, state->sha1_digest,
+                                        state->keylen);
+                setup_sg(sg_in, state->sha1_digest, state->keylen);
                 setup_sg(sg_out, state->session_key, state->keylen);
                 if (crypto_blkcipher_encrypt(&desc, sg_out, sg_in,
                                              state->keylen) != 0) {
                     printk(KERN_WARNING "mppe_rekey: cipher_encrypt failed\n");
                 }
         } else {
-                memcpy(state->session_key, InterimKey, state->keylen);
+                memcpy(state->session_key, state->sha1_digest, state->keylen);
         }
         if (state->keylen == 8) {
                 /* See RFC 3078 */