On Thu, Nov 22, 2018 at 06:00:16PM +0800, Pan Bian wrote: > 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> I don't think this patch is needed. > --- > 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; We can safely drop the reference to the algorithm because the spawn is now meant to hold a reference to it. As long as the spawn is alive so will the algorithm. Cheers, -- Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
