crypto: do not free algorithm before using

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.

Fixes: 79c65d179a40 ("crypto: cbc - Convert to skcipher")
Fixes: a7d85e06ed80 ("crypto: cfb - add support for Cipher FeedBack mode")
Fixes: 043a44001b9e ("crypto: pcbc - Convert to skcipher")
Cc: <stable@vger.kernel.org>
Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/cbc.c b/crypto/cbc.c
index b761b1f9c6ca161c8eb3a9340ab50b69374671bc..dd5f332fd5668985c9e904b35ad56d47b34ed383 100644 (file)
--- 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 a0d68c09e1b9c53dd9eb4fb9bd08238d24b70d44..20987d0e09d89ceafbd51d3b61b321dc58a56862 100644 (file)
--- 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 ef802f6e964218f06d00b035fc66d960cd4ce700..8aa10144407c04f936061c51d823d932660e2caa 100644 (file)
--- 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;