crypto: rsa-pkcs1pad - use clearer variable names

The new convention for akcipher_alg::verify makes it unclear which
values are the lengths of the signature and digest.  Add local variables
to make it clearer what is going on.

Also rename the digest_size variable in pkcs1pad_sign(), as it is
actually the digest *info* size, not the digest size which is different.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/rsa-pkcs1pad.c b/crypto/rsa-pkcs1pad.c
index 9d80483..3285e3a 100644 (file)
--- a/crypto/rsa-pkcs1pad.c
+++ b/crypto/rsa-pkcs1pad.c
@@ -385,15 +385,15 @@ static int pkcs1pad_sign(struct akcipher_request *req)
        struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
        const struct rsa_asn1_template *digest_info = ictx->digest_info;
        int err;
-       unsigned int ps_end, digest_size = 0;
+       unsigned int ps_end, digest_info_size = 0;
 
        if (!ctx->key_size)
                return -EINVAL;
 
        if (digest_info)
-               digest_size = digest_info->size;
+               digest_info_size = digest_info->size;
 
-       if (req->src_len + digest_size > ctx->key_size - 11)
+       if (req->src_len + digest_info_size > ctx->key_size - 11)
                return -EOVERFLOW;
 
        if (req->dst_len < ctx->key_size) {
@@ -406,7 +406,7 @@ static int pkcs1pad_sign(struct akcipher_request *req)
        if (!req_ctx->in_buf)
                return -ENOMEM;
 
-       ps_end = ctx->key_size - digest_size - req->src_len - 2;
+       ps_end = ctx->key_size - digest_info_size - req->src_len - 2;
        req_ctx->in_buf[0] = 0x01;
        memset(req_ctx->in_buf + 1, 0xff, ps_end - 1);
        req_ctx->in_buf[ps_end] = 0x00;
@@ -441,6 +441,8 @@ static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
        struct akcipher_instance *inst = akcipher_alg_instance(tfm);
        struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
        const struct rsa_asn1_template *digest_info = ictx->digest_info;
+       const unsigned int sig_size = req->src_len;
+       const unsigned int digest_size = req->dst_len;
        unsigned int dst_len;
        unsigned int pos;
        u8 *out_buf;
@@ -487,20 +489,19 @@ static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
 
        err = 0;
 
-       if (req->dst_len != dst_len - pos) {
+       if (digest_size != dst_len - pos) {
                err = -EKEYREJECTED;
                req->dst_len = dst_len - pos;
                goto done;
        }
        /* Extract appended digest. */
        sg_pcopy_to_buffer(req->src,
-                          sg_nents_for_len(req->src,
-                                           req->src_len + req->dst_len),
+                          sg_nents_for_len(req->src, sig_size + digest_size),
                           req_ctx->out_buf + ctx->key_size,
-                          req->dst_len, req->src_len);
+                          digest_size, sig_size);
        /* Do the actual verification step. */
        if (memcmp(req_ctx->out_buf + ctx->key_size, out_buf + pos,
-                  req->dst_len) != 0)
+                  digest_size) != 0)
                err = -EKEYREJECTED;
 done:
        kfree_sensitive(req_ctx->out_buf);
@@ -536,14 +537,15 @@ static int pkcs1pad_verify(struct akcipher_request *req)
        struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
        struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
        struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
+       const unsigned int sig_size = req->src_len;
+       const unsigned int digest_size = req->dst_len;
        int err;
 
-       if (WARN_ON(req->dst) ||
-           WARN_ON(!req->dst_len) ||
-           !ctx->key_size || req->src_len != ctx->key_size)
+       if (WARN_ON(req->dst) || WARN_ON(!digest_size) ||
+           !ctx->key_size || sig_size != ctx->key_size)
                return -EINVAL;
 
-       req_ctx->out_buf = kmalloc(ctx->key_size + req->dst_len, GFP_KERNEL);
+       req_ctx->out_buf = kmalloc(ctx->key_size + digest_size, GFP_KERNEL);
        if (!req_ctx->out_buf)
                return -ENOMEM;
 
@@ -556,8 +558,7 @@ static int pkcs1pad_verify(struct akcipher_request *req)
 
        /* Reuse input buffer, output to a new buffer */
        akcipher_request_set_crypt(&req_ctx->child_req, req->src,
-                                  req_ctx->out_sg, req->src_len,
-                                  ctx->key_size);
+                                  req_ctx->out_sg, sig_size, ctx->key_size);
 
        err = crypto_akcipher_encrypt(&req_ctx->child_req);
        if (err != -EINPROGRESS && err != -EBUSY)