The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From e5bde04ccce64d808f8b00a489a1fe5825d285cb Mon Sep 17 00:00:00 2001
From: Pan Bian bianpan2016@163.com Date: Thu, 22 Nov 2018 18:00:16 +0800 Subject: [PATCH] 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 b761b1f9c6ca..dd5f332fd566 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 a0d68c09e1b9..20987d0e09d8 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 ef802f6e9642..8aa10144407c 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;