Merge tag 'drm-misc-fixes-2017-09-28-1' of git://anongit.freedesktop.org/git/drm...

[linux.git] / crypto / ecdh.c

diff --git a/crypto/ecdh.c b/crypto/ecdh.c
index 61c7708905d01ec6745c03352579b2173fc6c87f..4271fc77d2616ef4a86d1509e8c44aeee33f4f72 100644 (file)
--- a/crypto/ecdh.c
+++ b/crypto/ecdh.c
@@ -20,8 +20,6 @@ struct ecdh_ctx {
        unsigned int curve_id;
        unsigned int ndigits;
        u64 private_key[ECC_MAX_DIGITS];
-       u64 public_key[2 * ECC_MAX_DIGITS];
-       u64 shared_secret[ECC_MAX_DIGITS];
 };
 
 static inline struct ecdh_ctx *ecdh_get_ctx(struct crypto_kpp *tfm)
@@ -70,41 +68,58 @@ static int ecdh_set_secret(struct crypto_kpp *tfm, const void *buf,
 
 static int ecdh_compute_value(struct kpp_request *req)
 {
-       int ret = 0;
        struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
        struct ecdh_ctx *ctx = ecdh_get_ctx(tfm);
-       size_t copied, nbytes;
+       u64 *public_key;
+       u64 *shared_secret = NULL;
        void *buf;
+       size_t copied, nbytes, public_key_sz;
+       int ret = -ENOMEM;
 
        nbytes = ctx->ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
+       /* Public part is a point thus it has both coordinates */
+       public_key_sz = 2 * nbytes;
+
+       public_key = kmalloc(public_key_sz, GFP_KERNEL);
+       if (!public_key)
+               return -ENOMEM;
 
        if (req->src) {
-               copied = sg_copy_to_buffer(req->src, 1, ctx->public_key,
-                                          2 * nbytes);
-               if (copied != 2 * nbytes)
-                       return -EINVAL;
+               shared_secret = kmalloc(nbytes, GFP_KERNEL);
+               if (!shared_secret)
+                       goto free_pubkey;
+
+               copied = sg_copy_to_buffer(req->src, 1, public_key,
+                                          public_key_sz);
+               if (copied != public_key_sz) {
+                       ret = -EINVAL;
+                       goto free_all;
+               }
 
                ret = crypto_ecdh_shared_secret(ctx->curve_id, ctx->ndigits,
-                                               ctx->private_key,
-                                               ctx->public_key,
-                                               ctx->shared_secret);
+                                               ctx->private_key, public_key,
+                                               shared_secret);
 
-               buf = ctx->shared_secret;
+               buf = shared_secret;
        } else {
                ret = ecc_make_pub_key(ctx->curve_id, ctx->ndigits,
-                                      ctx->private_key, ctx->public_key);
-               buf = ctx->public_key;
-               /* Public part is a point thus it has both coordinates */
-               nbytes *= 2;
+                                      ctx->private_key, public_key);
+               buf = public_key;
+               nbytes = public_key_sz;
        }
 
        if (ret < 0)
-               return ret;
+               goto free_all;
 
        copied = sg_copy_from_buffer(req->dst, 1, buf, nbytes);
        if (copied != nbytes)
-               return -EINVAL;
+               ret = -EINVAL;
 
+       /* fall through */
+free_all:
+       kzfree(shared_secret);
+free_pubkey:
+       kfree(public_key);
        return ret;
 }