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@xxxxxxx> --- 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
