crypto: user - fix use_after_free of struct xxx_request

All crypto_stats functions use the struct xxx_request for feeding stats,
but in some case this structure could already be freed.

For fixing this, the needed parameters (len and alg) will be stored
before the request being executed.
Fixes: cac5818c25d0 ("crypto: user - Implement a generic crypto statistics")
Reported-by: syzbot <syzbot+6939a606a5305e9e9799@syzkaller.appspotmail.com>

Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 9 insertions, 39 deletions

diff --git a/include/crypto/kpp.h b/include/crypto/kpp.h
index bd5103a80919..1a97e1601422 100644
--- a/include/crypto/kpp.h
+++ b/include/crypto/kpp.h
@@ -268,42 +268,6 @@ struct kpp_secret {
 	unsigned short len;
 };
 
-static inline void crypto_stat_kpp_set_secret(struct crypto_kpp *tfm, int ret)
-{
-#ifdef CONFIG_CRYPTO_STATS
-	if (ret)
-		atomic64_inc(&tfm->base.__crt_alg->kpp_err_cnt);
-	else
-		atomic64_inc(&tfm->base.__crt_alg->setsecret_cnt);
-#endif
-}
-
-static inline void crypto_stat_kpp_generate_public_key(struct kpp_request *req,
-						       int ret)
-{
-#ifdef CONFIG_CRYPTO_STATS
-	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
-
-	if (ret)
-		atomic64_inc(&tfm->base.__crt_alg->kpp_err_cnt);
-	else
-		atomic64_inc(&tfm->base.__crt_alg->generate_public_key_cnt);
-#endif
-}
-
-static inline void crypto_stat_kpp_compute_shared_secret(struct kpp_request *req,
-							 int ret)
-{
-#ifdef CONFIG_CRYPTO_STATS
-	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
-
-	if (ret)
-		atomic64_inc(&tfm->base.__crt_alg->kpp_err_cnt);
-	else
-		atomic64_inc(&tfm->base.__crt_alg->compute_shared_secret_cnt);
-#endif
-}
-
 /**
  * crypto_kpp_set_secret() - Invoke kpp operation
  *
@@ -323,10 +287,12 @@ static inline int crypto_kpp_set_secret(struct crypto_kpp *tfm,
 					const void *buffer, unsigned int len)
 {
 	struct kpp_alg *alg = crypto_kpp_alg(tfm);
+	struct crypto_alg *calg = tfm->base.__crt_alg;
 	int ret;
 
+	crypto_stats_get(calg);
 	ret = alg->set_secret(tfm, buffer, len);
-	crypto_stat_kpp_set_secret(tfm, ret);
+	crypto_stats_kpp_set_secret(calg, ret);
 	return ret;
 }
 
@@ -347,10 +313,12 @@ static inline int crypto_kpp_generate_public_key(struct kpp_request *req)
 {
 	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
 	struct kpp_alg *alg = crypto_kpp_alg(tfm);
+	struct crypto_alg *calg = tfm->base.__crt_alg;
 	int ret;
 
+	crypto_stats_get(calg);
 	ret = alg->generate_public_key(req);
-	crypto_stat_kpp_generate_public_key(req, ret);
+	crypto_stats_kpp_generate_public_key(calg, ret);
 	return ret;
 }
 
@@ -368,10 +336,12 @@ static inline int crypto_kpp_compute_shared_secret(struct kpp_request *req)
 {
 	struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
 	struct kpp_alg *alg = crypto_kpp_alg(tfm);
+	struct crypto_alg *calg = tfm->base.__crt_alg;
 	int ret;
 
+	crypto_stats_get(calg);
 	ret = alg->compute_shared_secret(req);
-	crypto_stat_kpp_compute_shared_secret(req, ret);
+	crypto_stats_kpp_compute_shared_secret(calg, ret);
 	return ret;
 }