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, 71 insertions, 34 deletions

diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index b109b50906e7..e2fd24714e00 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -557,6 +557,69 @@ struct crypto_alg {
 
 } CRYPTO_MINALIGN_ATTR;
 
+#ifdef CONFIG_CRYPTO_STATS
+void crypto_stats_get(struct crypto_alg *alg);
+void crypto_stats_ablkcipher_encrypt(unsigned int nbytes, int ret, struct crypto_alg *alg);
+void crypto_stats_ablkcipher_decrypt(unsigned int nbytes, int ret, struct crypto_alg *alg);
+void crypto_stats_aead_encrypt(unsigned int cryptlen, struct crypto_alg *alg, int ret);
+void crypto_stats_aead_decrypt(unsigned int cryptlen, struct crypto_alg *alg, int ret);
+void crypto_stats_ahash_update(unsigned int nbytes, int ret, struct crypto_alg *alg);
+void crypto_stats_ahash_final(unsigned int nbytes, int ret, struct crypto_alg *alg);
+void crypto_stats_akcipher_encrypt(unsigned int src_len, int ret, struct crypto_alg *alg);
+void crypto_stats_akcipher_decrypt(unsigned int src_len, int ret, struct crypto_alg *alg);
+void crypto_stats_akcipher_sign(int ret, struct crypto_alg *alg);
+void crypto_stats_akcipher_verify(int ret, struct crypto_alg *alg);
+void crypto_stats_compress(unsigned int slen, int ret, struct crypto_alg *alg);
+void crypto_stats_decompress(unsigned int slen, int ret, struct crypto_alg *alg);
+void crypto_stats_kpp_set_secret(struct crypto_alg *alg, int ret);
+void crypto_stats_kpp_generate_public_key(struct crypto_alg *alg, int ret);
+void crypto_stats_kpp_compute_shared_secret(struct crypto_alg *alg, int ret);
+void crypto_stats_rng_seed(struct crypto_alg *alg, int ret);
+void crypto_stats_rng_generate(struct crypto_alg *alg, unsigned int dlen, int ret);
+void crypto_stats_skcipher_encrypt(unsigned int cryptlen, int ret, struct crypto_alg *alg);
+void crypto_stats_skcipher_decrypt(unsigned int cryptlen, int ret, struct crypto_alg *alg);
+#else
+static inline void crypto_stats_get(struct crypto_alg *alg)
+{}
+static inline void crypto_stats_ablkcipher_encrypt(unsigned int nbytes, int ret, struct crypto_alg *alg)
+{}
+static inline void crypto_stats_ablkcipher_decrypt(unsigned int nbytes, int ret, struct crypto_alg *alg)
+{}
+static inline void crypto_stats_aead_encrypt(unsigned int cryptlen, struct crypto_alg *alg, int ret)
+{}
+static inline void crypto_stats_aead_decrypt(unsigned int cryptlen, struct crypto_alg *alg, int ret)
+{}
+static inline void crypto_stats_ahash_update(unsigned int nbytes, int ret, struct crypto_alg *alg)
+{}
+static inline void crypto_stats_ahash_final(unsigned int nbytes, int ret, struct crypto_alg *alg)
+{}
+static inline void crypto_stats_akcipher_encrypt(unsigned int src_len, int ret, struct crypto_alg *alg)
+{}
+static inline void crypto_stats_akcipher_decrypt(unsigned int src_len, int ret, struct crypto_alg *alg)
+{}
+static inline void crypto_stats_akcipher_sign(int ret, struct crypto_alg *alg)
+{}
+static inline void crypto_stats_akcipher_verify(int ret, struct crypto_alg *alg)
+{}
+static inline void crypto_stats_compress(unsigned int slen, int ret, struct crypto_alg *alg)
+{}
+static inline void crypto_stats_decompress(unsigned int slen, int ret, struct crypto_alg *alg)
+{}
+static inline void crypto_stats_kpp_set_secret(struct crypto_alg *alg, int ret)
+{}
+static inline void crypto_stats_kpp_generate_public_key(struct crypto_alg *alg, int ret)
+{}
+static inline void crypto_stats_kpp_compute_shared_secret(struct crypto_alg *alg, int ret)
+{}
+static inline void crypto_stats_rng_seed(struct crypto_alg *alg, int ret)
+{}
+static inline void crypto_stats_rng_generate(struct crypto_alg *alg, unsigned int dlen, int ret)
+{}
+static inline void crypto_stats_skcipher_encrypt(unsigned int cryptlen, int ret, struct crypto_alg *alg)
+{}
+static inline void crypto_stats_skcipher_decrypt(unsigned int cryptlen, int ret, struct crypto_alg *alg)
+{}
+#endif
 /*
  * A helper struct for waiting for completion of async crypto ops
  */
@@ -975,38 +1038,6 @@ static inline struct crypto_ablkcipher *crypto_ablkcipher_reqtfm(
 	return __crypto_ablkcipher_cast(req->base.tfm);
 }
 
-static inline void crypto_stat_ablkcipher_encrypt(struct ablkcipher_request *req,
-						  int ret)
-{
-#ifdef CONFIG_CRYPTO_STATS
-	struct ablkcipher_tfm *crt =
-		crypto_ablkcipher_crt(crypto_ablkcipher_reqtfm(req));
-
-	if (ret && ret != -EINPROGRESS && ret != -EBUSY) {
-		atomic64_inc(&crt->base->base.__crt_alg->cipher_err_cnt);
-	} else {
-		atomic64_inc(&crt->base->base.__crt_alg->encrypt_cnt);
-		atomic64_add(req->nbytes, &crt->base->base.__crt_alg->encrypt_tlen);
-	}
-#endif
-}
-
-static inline void crypto_stat_ablkcipher_decrypt(struct ablkcipher_request *req,
-						  int ret)
-{
-#ifdef CONFIG_CRYPTO_STATS
-	struct ablkcipher_tfm *crt =
-		crypto_ablkcipher_crt(crypto_ablkcipher_reqtfm(req));
-
-	if (ret && ret != -EINPROGRESS && ret != -EBUSY) {
-		atomic64_inc(&crt->base->base.__crt_alg->cipher_err_cnt);
-	} else {
-		atomic64_inc(&crt->base->base.__crt_alg->decrypt_cnt);
-		atomic64_add(req->nbytes, &crt->base->base.__crt_alg->decrypt_tlen);
-	}
-#endif
-}
-
 /**
  * crypto_ablkcipher_encrypt() - encrypt plaintext
  * @req: reference to the ablkcipher_request handle that holds all information
@@ -1022,10 +1053,13 @@ static inline int crypto_ablkcipher_encrypt(struct ablkcipher_request *req)
 {
 	struct ablkcipher_tfm *crt =
 		crypto_ablkcipher_crt(crypto_ablkcipher_reqtfm(req));
+	struct crypto_alg *alg = crt->base->base.__crt_alg;
+	unsigned int nbytes = req->nbytes;
 	int ret;
 
+	crypto_stats_get(alg);
 	ret = crt->encrypt(req);
-	crypto_stat_ablkcipher_encrypt(req, ret);
+	crypto_stats_ablkcipher_encrypt(nbytes, ret, alg);
 	return ret;
 }
 
@@ -1044,10 +1078,13 @@ static inline int crypto_ablkcipher_decrypt(struct ablkcipher_request *req)
 {
 	struct ablkcipher_tfm *crt =
 		crypto_ablkcipher_crt(crypto_ablkcipher_reqtfm(req));
+	struct crypto_alg *alg = crt->base->base.__crt_alg;
+	unsigned int nbytes = req->nbytes;
 	int ret;
 
+	crypto_stats_get(alg);
 	ret = crt->decrypt(req);
-	crypto_stat_ablkcipher_decrypt(req, ret);
+	crypto_stats_ablkcipher_decrypt(nbytes, ret, alg);
 	return ret;
 }