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crypto: rsa-pkcs1pad - Require hash to be present
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The only user of rsa-pkcs1pad always uses the hash so there is
no reason to support the case of not having a hash.

This patch also changes the digest info lookup so that it is
only done once during template instantiation rather than on each
operation.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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@herbertx
herbertx committed Jul 1, 2016
1 parent 127827b commit c0d20d2
Showing 1 changed file with 30 additions and 53 deletions.
83 changes: 30 additions & 53 deletions crypto/rsa-pkcs1pad.c
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Original file line number Diff line number Diff line change
Expand Up @@ -92,13 +92,12 @@ static const struct rsa_asn1_template *rsa_lookup_asn1(const char *name)

struct pkcs1pad_ctx {
struct crypto_akcipher *child;
const char *hash_name;
unsigned int key_size;
};

struct pkcs1pad_inst_ctx {
struct crypto_akcipher_spawn spawn;
const char *hash_name;
const struct rsa_asn1_template *digest_info;
};

struct pkcs1pad_request {
Expand Down Expand Up @@ -416,20 +415,16 @@ static int pkcs1pad_sign(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 struct rsa_asn1_template *digest_info = NULL;
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;
int err;
unsigned int ps_end, digest_size = 0;

if (!ctx->key_size)
return -EINVAL;

if (ctx->hash_name) {
digest_info = rsa_lookup_asn1(ctx->hash_name);
if (!digest_info)
return -EINVAL;

digest_size = digest_info->size;
}
digest_size = digest_info->size;

if (req->src_len + digest_size > ctx->key_size - 11)
return -EOVERFLOW;
Expand Down Expand Up @@ -462,10 +457,8 @@ static int pkcs1pad_sign(struct akcipher_request *req)
memset(req_ctx->in_buf + 1, 0xff, ps_end - 1);
req_ctx->in_buf[ps_end] = 0x00;

if (digest_info) {
memcpy(req_ctx->in_buf + ps_end + 1, digest_info->data,
digest_info->size);
}
memcpy(req_ctx->in_buf + ps_end + 1, digest_info->data,
digest_info->size);

pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
ctx->key_size - 1 - req->src_len, req->src);
Expand Down Expand Up @@ -499,7 +492,9 @@ static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
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 struct rsa_asn1_template *digest_info;
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;
unsigned int pos;

if (err == -EOVERFLOW)
Expand Down Expand Up @@ -527,17 +522,11 @@ static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
goto done;
pos++;

if (ctx->hash_name) {
digest_info = rsa_lookup_asn1(ctx->hash_name);
if (!digest_info)
goto done;
if (memcmp(req_ctx->out_buf + pos, digest_info->data,
digest_info->size))
goto done;

if (memcmp(req_ctx->out_buf + pos, digest_info->data,
digest_info->size))
goto done;

pos += digest_info->size;
}
pos += digest_info->size;

err = 0;

Expand Down Expand Up @@ -626,12 +615,11 @@ static int pkcs1pad_init_tfm(struct crypto_akcipher *tfm)
struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
struct crypto_akcipher *child_tfm;

child_tfm = crypto_spawn_akcipher(akcipher_instance_ctx(inst));
child_tfm = crypto_spawn_akcipher(&ictx->spawn);
if (IS_ERR(child_tfm))
return PTR_ERR(child_tfm);

ctx->child = child_tfm;
ctx->hash_name = ictx->hash_name;
return 0;
}

Expand All @@ -648,12 +636,12 @@ static void pkcs1pad_free(struct akcipher_instance *inst)
struct crypto_akcipher_spawn *spawn = &ctx->spawn;

crypto_drop_akcipher(spawn);
kfree(ctx->hash_name);
kfree(inst);
}

static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
{
const struct rsa_asn1_template *digest_info;
struct crypto_attr_type *algt;
struct akcipher_instance *inst;
struct pkcs1pad_inst_ctx *ctx;
Expand All @@ -676,15 +664,19 @@ static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)

hash_name = crypto_attr_alg_name(tb[2]);
if (IS_ERR(hash_name))
hash_name = NULL;
return PTR_ERR(hash_name);

digest_info = rsa_lookup_asn1(hash_name);
if (!digest_info)
return -EINVAL;

inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
if (!inst)
return -ENOMEM;

ctx = akcipher_instance_ctx(inst);
spawn = &ctx->spawn;
ctx->hash_name = hash_name ? kstrdup(hash_name, GFP_KERNEL) : NULL;
ctx->digest_info = digest_info;

crypto_set_spawn(&spawn->base, akcipher_crypto_instance(inst));
err = crypto_grab_akcipher(spawn, rsa_alg_name, 0,
Expand All @@ -696,27 +688,14 @@ static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)

err = -ENAMETOOLONG;

if (!hash_name) {
if (snprintf(inst->alg.base.cra_name,
CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
rsa_alg->base.cra_name) >=
CRYPTO_MAX_ALG_NAME ||
snprintf(inst->alg.base.cra_driver_name,
CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
rsa_alg->base.cra_driver_name) >=
CRYPTO_MAX_ALG_NAME)
if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
"pkcs1pad(%s,%s)", rsa_alg->base.cra_name, hash_name) >=
CRYPTO_MAX_ALG_NAME ||
snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
"pkcs1pad(%s,%s)",
rsa_alg->base.cra_driver_name, hash_name) >=
CRYPTO_MAX_ALG_NAME)
goto out_drop_alg;
} else {
if (snprintf(inst->alg.base.cra_name,
CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s,%s)",
rsa_alg->base.cra_name, hash_name) >=
CRYPTO_MAX_ALG_NAME ||
snprintf(inst->alg.base.cra_driver_name,
CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s,%s)",
rsa_alg->base.cra_driver_name, hash_name) >=
CRYPTO_MAX_ALG_NAME)
goto out_free_hash;
}

inst->alg.base.cra_flags = rsa_alg->base.cra_flags & CRYPTO_ALG_ASYNC;
inst->alg.base.cra_priority = rsa_alg->base.cra_priority;
Expand All @@ -738,12 +717,10 @@ static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)

err = akcipher_register_instance(tmpl, inst);
if (err)
goto out_free_hash;
goto out_drop_alg;

return 0;

out_free_hash:
kfree(ctx->hash_name);
out_drop_alg:
crypto_drop_akcipher(spawn);
out_free_inst:
Expand Down

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