crypto: rsassa-pkcs1 - Copy source data for SG list

As virtual addresses in general may not be suitable for DMA, always
perform a copy before using them in an SG list.

Fixes: 1e562deacecc ("crypto: rsassa-pkcs1 - Migrate to sig_alg backend")
Reported-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/rsassa-pkcs1.c b/crypto/rsassa-pkcs1.c
index 4d077fc9607672061bdf14ebc23a12cee18364c9..f68ffd338f483f12358e37f2b01c32ae169c2323 100644 (file)
--- a/crypto/rsassa-pkcs1.c
+++ b/crypto/rsassa-pkcs1.c
@@ -163,10 +163,6 @@ static int rsassa_pkcs1_sign(struct crypto_sig *tfm,
        struct rsassa_pkcs1_inst_ctx *ictx = sig_instance_ctx(inst);
        const struct hash_prefix *hash_prefix = ictx->hash_prefix;
        struct rsassa_pkcs1_ctx *ctx = crypto_sig_ctx(tfm);
-       unsigned int child_reqsize = crypto_akcipher_reqsize(ctx->child);
-       struct akcipher_request *child_req __free(kfree_sensitive) = NULL;
-       struct scatterlist in_sg[3], out_sg;
-       struct crypto_wait cwait;
        unsigned int pad_len;
        unsigned int ps_end;
        unsigned int len;
@@ -187,37 +183,25 @@ static int rsassa_pkcs1_sign(struct crypto_sig *tfm,
 
        pad_len = ctx->key_size - slen - hash_prefix->size - 1;
 
-       child_req = kmalloc(sizeof(*child_req) + child_reqsize + pad_len,
-                           GFP_KERNEL);
-       if (!child_req)
-               return -ENOMEM;
-
        /* RFC 8017 sec 8.2.1 step 1 - EMSA-PKCS1-v1_5 encoding generation */
-       in_buf = (u8 *)(child_req + 1) + child_reqsize;
+       in_buf = dst;
+       memmove(in_buf + pad_len + hash_prefix->size, src, slen);
+       memcpy(in_buf + pad_len, hash_prefix->data, hash_prefix->size);
+
        ps_end = pad_len - 1;
        in_buf[0] = 0x01;
        memset(in_buf + 1, 0xff, ps_end - 1);
        in_buf[ps_end] = 0x00;
 
-       /* RFC 8017 sec 8.2.1 step 2 - RSA signature */
-       crypto_init_wait(&cwait);
-       sg_init_table(in_sg, 3);
-       sg_set_buf(&in_sg[0], in_buf, pad_len);
-       sg_set_buf(&in_sg[1], hash_prefix->data, hash_prefix->size);
-       sg_set_buf(&in_sg[2], src, slen);
-       sg_init_one(&out_sg, dst, dlen);
-       akcipher_request_set_tfm(child_req, ctx->child);
-       akcipher_request_set_crypt(child_req, in_sg, &out_sg,
-                                  ctx->key_size - 1, dlen);
-       akcipher_request_set_callback(child_req, CRYPTO_TFM_REQ_MAY_SLEEP,
-                                     crypto_req_done, &cwait);
 
-       err = crypto_akcipher_decrypt(child_req);
-       err = crypto_wait_req(err, &cwait);
-       if (err)
+       /* RFC 8017 sec 8.2.1 step 2 - RSA signature */
+       err = crypto_akcipher_sync_decrypt(ctx->child, in_buf,
+                                          ctx->key_size - 1, in_buf,
+                                          ctx->key_size);
+       if (err < 0)
                return err;
 
-       len = child_req->dst_len;
+       len = err;
        pad_len = ctx->key_size - len;
 
        /* Four billion to one */
@@ -239,8 +223,8 @@ static int rsassa_pkcs1_verify(struct crypto_sig *tfm,
        struct rsassa_pkcs1_ctx *ctx = crypto_sig_ctx(tfm);
        unsigned int child_reqsize = crypto_akcipher_reqsize(ctx->child);
        struct akcipher_request *child_req __free(kfree_sensitive) = NULL;
-       struct scatterlist in_sg, out_sg;
        struct crypto_wait cwait;
+       struct scatterlist sg;
        unsigned int dst_len;
        unsigned int pos;
        u8 *out_buf;
@@ -259,13 +243,12 @@ static int rsassa_pkcs1_verify(struct crypto_sig *tfm,
                return -ENOMEM;
 
        out_buf = (u8 *)(child_req + 1) + child_reqsize;
+       memcpy(out_buf, src, slen);
 
        crypto_init_wait(&cwait);
-       sg_init_one(&in_sg, src, slen);
-       sg_init_one(&out_sg, out_buf, ctx->key_size);
+       sg_init_one(&sg, out_buf, slen);
        akcipher_request_set_tfm(child_req, ctx->child);
-       akcipher_request_set_crypt(child_req, &in_sg, &out_sg,
-                                  slen, ctx->key_size);
+       akcipher_request_set_crypt(child_req, &sg, &sg, slen, slen);
        akcipher_request_set_callback(child_req, CRYPTO_TFM_REQ_MAY_SLEEP,
                                      crypto_req_done, &cwait);