From: Pan Bian <bianpan2016@163.com>
To: Herbert Xu <herbert@gondor.apana.org.au>,
"David S. Miller" <davem@davemloft.net>
Cc: linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
Pan Bian <bianpan2016@163.com>
Subject: [PATCH] crypto: do not free algorithm before using
Date: Thu, 22 Nov 2018 18:00:16 +0800 [thread overview]
Message-ID: <1542880816-63838-1-git-send-email-bianpan2016@163.com> (raw)
In multiple functions, the algorithm fields are read after its reference
is dropped through crypto_mod_put. In this case, the algorithm memory
may be freed, resulting in use-after-free bugs. This patch delays the
put operation until the algorithm is never used.
Signed-off-by: Pan Bian <bianpan2016@163.com>
---
crypto/cbc.c | 6 ++++--
crypto/cfb.c | 6 ++++--
crypto/pcbc.c | 6 ++++--
3 files changed, 12 insertions(+), 6 deletions(-)
diff --git a/crypto/cbc.c b/crypto/cbc.c
index b761b1f..dd5f332 100644
--- a/crypto/cbc.c
+++ b/crypto/cbc.c
@@ -140,9 +140,8 @@ static int crypto_cbc_create(struct crypto_template *tmpl, struct rtattr **tb)
spawn = skcipher_instance_ctx(inst);
err = crypto_init_spawn(spawn, alg, skcipher_crypto_instance(inst),
CRYPTO_ALG_TYPE_MASK);
- crypto_mod_put(alg);
if (err)
- goto err_free_inst;
+ goto err_put_alg;
err = crypto_inst_setname(skcipher_crypto_instance(inst), "cbc", alg);
if (err)
@@ -174,12 +173,15 @@ static int crypto_cbc_create(struct crypto_template *tmpl, struct rtattr **tb)
err = skcipher_register_instance(tmpl, inst);
if (err)
goto err_drop_spawn;
+ crypto_mod_put(alg);
out:
return err;
err_drop_spawn:
crypto_drop_spawn(spawn);
+err_put_alg:
+ crypto_mod_put(alg);
err_free_inst:
kfree(inst);
goto out;
diff --git a/crypto/cfb.c b/crypto/cfb.c
index a0d68c0..20987d0 100644
--- a/crypto/cfb.c
+++ b/crypto/cfb.c
@@ -286,9 +286,8 @@ static int crypto_cfb_create(struct crypto_template *tmpl, struct rtattr **tb)
spawn = skcipher_instance_ctx(inst);
err = crypto_init_spawn(spawn, alg, skcipher_crypto_instance(inst),
CRYPTO_ALG_TYPE_MASK);
- crypto_mod_put(alg);
if (err)
- goto err_free_inst;
+ goto err_put_alg;
err = crypto_inst_setname(skcipher_crypto_instance(inst), "cfb", alg);
if (err)
@@ -317,12 +316,15 @@ static int crypto_cfb_create(struct crypto_template *tmpl, struct rtattr **tb)
err = skcipher_register_instance(tmpl, inst);
if (err)
goto err_drop_spawn;
+ crypto_mod_put(alg);
out:
return err;
err_drop_spawn:
crypto_drop_spawn(spawn);
+err_put_alg:
+ crypto_mod_put(alg);
err_free_inst:
kfree(inst);
goto out;
diff --git a/crypto/pcbc.c b/crypto/pcbc.c
index ef802f6..8aa1014 100644
--- a/crypto/pcbc.c
+++ b/crypto/pcbc.c
@@ -244,9 +244,8 @@ static int crypto_pcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
spawn = skcipher_instance_ctx(inst);
err = crypto_init_spawn(spawn, alg, skcipher_crypto_instance(inst),
CRYPTO_ALG_TYPE_MASK);
- crypto_mod_put(alg);
if (err)
- goto err_free_inst;
+ goto err_put_alg;
err = crypto_inst_setname(skcipher_crypto_instance(inst), "pcbc", alg);
if (err)
@@ -275,12 +274,15 @@ static int crypto_pcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
err = skcipher_register_instance(tmpl, inst);
if (err)
goto err_drop_spawn;
+ crypto_mod_put(alg);
out:
return err;
err_drop_spawn:
crypto_drop_spawn(spawn);
+err_put_alg:
+ crypto_mod_put(alg);
err_free_inst:
kfree(inst);
goto out;
--
2.7.4
next reply other threads:[~2018-11-22 10:01 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-22 10:00 Pan Bian [this message]
2018-11-22 14:44 ` Herbert Xu
2018-11-23 1:05 ` PanBian
2018-11-23 2:36 ` Herbert Xu
2018-11-29 6:57 ` Herbert Xu
2018-11-29 7:47 ` PanBian
2018-11-29 8:29 ` Herbert Xu
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