From c2a28fdb2f4e0b1676709426d80a986dd601200e Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Tue, 18 Jan 2022 16:13:06 -0800 Subject: [PATCH] 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 Signed-off-by: Herbert Xu --- crypto/rsa-pkcs1pad.c | 31 ++++++++++++++++--------------- 1 file changed, 16 insertions(+), 15 deletions(-) diff --git a/crypto/rsa-pkcs1pad.c b/crypto/rsa-pkcs1pad.c index 9d804831c8b3..3285e3af43e1 100644 --- 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)