Messages in this thread | | | Subject | Re: [PATCH v2 2/2] crypto: Remove unnecessary memzero_explicit() | From | Christophe Leroy <> | Date | Tue, 14 Apr 2020 08:08:22 +0200 |
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Le 14/04/2020 à 00:28, Waiman Long a écrit : > Since kfree_sensitive() will do an implicit memzero_explicit(), there > is no need to call memzero_explicit() before it. Eliminate those > memzero_explicit() and simplify the call sites. For better correctness, > the setting of keylen is also moved down after the key pointer check. > > Signed-off-by: Waiman Long <longman@redhat.com> > --- > .../allwinner/sun8i-ce/sun8i-ce-cipher.c | 19 +++++------------- > .../allwinner/sun8i-ss/sun8i-ss-cipher.c | 20 +++++-------------- > drivers/crypto/amlogic/amlogic-gxl-cipher.c | 12 +++-------- > drivers/crypto/inside-secure/safexcel_hash.c | 3 +-- > 4 files changed, 14 insertions(+), 40 deletions(-) > > diff --git a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-cipher.c b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-cipher.c > index aa4e8fdc2b32..8358fac98719 100644 > --- a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-cipher.c > +++ b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-cipher.c > @@ -366,10 +366,7 @@ void sun8i_ce_cipher_exit(struct crypto_tfm *tfm) > { > struct sun8i_cipher_tfm_ctx *op = crypto_tfm_ctx(tfm); > > - if (op->key) { > - memzero_explicit(op->key, op->keylen); > - kfree(op->key); > - } > + kfree_sensitive(op->key); > crypto_free_sync_skcipher(op->fallback_tfm); > pm_runtime_put_sync_suspend(op->ce->dev); > } > @@ -391,14 +388,11 @@ int sun8i_ce_aes_setkey(struct crypto_skcipher *tfm, const u8 *key, > dev_dbg(ce->dev, "ERROR: Invalid keylen %u\n", keylen); > return -EINVAL; > } > - if (op->key) { > - memzero_explicit(op->key, op->keylen); > - kfree(op->key); > - } > - op->keylen = keylen; > + kfree_sensitive(op->key); > op->key = kmemdup(key, keylen, GFP_KERNEL | GFP_DMA); > if (!op->key) > return -ENOMEM; > + op->keylen = keylen;
Does it matter at all to ensure op->keylen is not set when of->key is NULL ? I'm not sure.
But if it does, then op->keylen should be set to 0 when freeing op->key.
> > crypto_sync_skcipher_clear_flags(op->fallback_tfm, CRYPTO_TFM_REQ_MASK); > crypto_sync_skcipher_set_flags(op->fallback_tfm, tfm->base.crt_flags & CRYPTO_TFM_REQ_MASK); > @@ -416,14 +410,11 @@ int sun8i_ce_des3_setkey(struct crypto_skcipher *tfm, const u8 *key, > if (err) > return err; > > - if (op->key) { > - memzero_explicit(op->key, op->keylen); > - kfree(op->key); > - } > - op->keylen = keylen; > + kfree_sensitive(op->key); > op->key = kmemdup(key, keylen, GFP_KERNEL | GFP_DMA); > if (!op->key) > return -ENOMEM; > + op->keylen = keylen;
Same comment as above.
> > crypto_sync_skcipher_clear_flags(op->fallback_tfm, CRYPTO_TFM_REQ_MASK); > crypto_sync_skcipher_set_flags(op->fallback_tfm, tfm->base.crt_flags & CRYPTO_TFM_REQ_MASK); > diff --git a/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-cipher.c b/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-cipher.c > index 5246ef4f5430..0495fbc27fcc 100644 > --- a/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-cipher.c > +++ b/drivers/crypto/allwinner/sun8i-ss/sun8i-ss-cipher.c > @@ -249,7 +249,6 @@ static int sun8i_ss_cipher(struct skcipher_request *areq) > offset = areq->cryptlen - ivsize; > if (rctx->op_dir & SS_DECRYPTION) { > memcpy(areq->iv, backup_iv, ivsize); > - memzero_explicit(backup_iv, ivsize); > kfree_sensitive(backup_iv); > } else { > scatterwalk_map_and_copy(areq->iv, areq->dst, offset, > @@ -367,10 +366,7 @@ void sun8i_ss_cipher_exit(struct crypto_tfm *tfm) > { > struct sun8i_cipher_tfm_ctx *op = crypto_tfm_ctx(tfm); > > - if (op->key) { > - memzero_explicit(op->key, op->keylen); > - kfree(op->key); > - } > + kfree_sensitive(op->key); > crypto_free_sync_skcipher(op->fallback_tfm); > pm_runtime_put_sync(op->ss->dev); > } > @@ -392,14 +388,11 @@ int sun8i_ss_aes_setkey(struct crypto_skcipher *tfm, const u8 *key, > dev_dbg(ss->dev, "ERROR: Invalid keylen %u\n", keylen); > return -EINVAL; > } > - if (op->key) { > - memzero_explicit(op->key, op->keylen); > - kfree(op->key); > - } > - op->keylen = keylen; > + kfree_sensitive(op->key); > op->key = kmemdup(key, keylen, GFP_KERNEL | GFP_DMA); > if (!op->key) > return -ENOMEM; > + op->keylen = keylen;
Same comment as above.
> > crypto_sync_skcipher_clear_flags(op->fallback_tfm, CRYPTO_TFM_REQ_MASK); > crypto_sync_skcipher_set_flags(op->fallback_tfm, tfm->base.crt_flags & CRYPTO_TFM_REQ_MASK); > @@ -418,14 +411,11 @@ int sun8i_ss_des3_setkey(struct crypto_skcipher *tfm, const u8 *key, > return -EINVAL; > } > > - if (op->key) { > - memzero_explicit(op->key, op->keylen); > - kfree(op->key); > - } > - op->keylen = keylen; > + kfree_sensitive(op->key); > op->key = kmemdup(key, keylen, GFP_KERNEL | GFP_DMA); > if (!op->key) > return -ENOMEM; > + op->keylen = keylen;
Same comment as above.
> > crypto_sync_skcipher_clear_flags(op->fallback_tfm, CRYPTO_TFM_REQ_MASK); > crypto_sync_skcipher_set_flags(op->fallback_tfm, tfm->base.crt_flags & CRYPTO_TFM_REQ_MASK); > diff --git a/drivers/crypto/amlogic/amlogic-gxl-cipher.c b/drivers/crypto/amlogic/amlogic-gxl-cipher.c > index fd1269900d67..6aa9ce7bbbd4 100644 > --- a/drivers/crypto/amlogic/amlogic-gxl-cipher.c > +++ b/drivers/crypto/amlogic/amlogic-gxl-cipher.c > @@ -341,10 +341,7 @@ void meson_cipher_exit(struct crypto_tfm *tfm) > { > struct meson_cipher_tfm_ctx *op = crypto_tfm_ctx(tfm); > > - if (op->key) { > - memzero_explicit(op->key, op->keylen); > - kfree(op->key); > - } > + kfree_sensitive(op->key); > crypto_free_sync_skcipher(op->fallback_tfm); > } > > @@ -368,14 +365,11 @@ int meson_aes_setkey(struct crypto_skcipher *tfm, const u8 *key, > dev_dbg(mc->dev, "ERROR: Invalid keylen %u\n", keylen); > return -EINVAL; > } > - if (op->key) { > - memzero_explicit(op->key, op->keylen); > - kfree(op->key); > - } > - op->keylen = keylen; > + kfree_sensitive(op->key); > op->key = kmemdup(key, keylen, GFP_KERNEL | GFP_DMA); > if (!op->key) > return -ENOMEM; > + op->keylen = keylen;
Same comment as above.
> > return crypto_sync_skcipher_setkey(op->fallback_tfm, key, keylen); > } > diff --git a/drivers/crypto/inside-secure/safexcel_hash.c b/drivers/crypto/inside-secure/safexcel_hash.c > index 43962bc709c6..4a2d162914de 100644 > --- a/drivers/crypto/inside-secure/safexcel_hash.c > +++ b/drivers/crypto/inside-secure/safexcel_hash.c > @@ -1081,8 +1081,7 @@ static int safexcel_hmac_init_pad(struct ahash_request *areq, > } > > /* Avoid leaking */ > - memzero_explicit(keydup, keylen); > - kfree(keydup); > + kfree_sensitive(keydup); > > if (ret) > return ret; >
Christophe
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