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Subject[PATCH v3 2/3] crypto: Remove unnecessary memzero_explicit()
Date
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,
keylen is cleared if key memory allocation fails.

Signed-off-by: Waiman Long <longman@redhat.com>
---
.../allwinner/sun8i-ce/sun8i-ce-cipher.c | 23 +++++++-----------
.../allwinner/sun8i-ss/sun8i-ss-cipher.c | 24 +++++++------------
drivers/crypto/amlogic/amlogic-gxl-cipher.c | 14 ++++-------
drivers/crypto/inside-secure/safexcel_hash.c | 3 +--
4 files changed, 24 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..a2bac10d2876 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 +388,13 @@ 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);
- }
+ kfree_sensitive(op->key);
op->keylen = keylen;
op->key = kmemdup(key, keylen, GFP_KERNEL | GFP_DMA);
- if (!op->key)
+ if (unlikely(!op->key)) {
+ op->keylen = 0;
return -ENOMEM;
+ }

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 +412,13 @@ 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);
- }
+ kfree_sensitive(op->key);
op->keylen = keylen;
op->key = kmemdup(key, keylen, GFP_KERNEL | GFP_DMA);
- if (!op->key)
+ if (unlikely(!op->key)) {
+ op->keylen = 0;
return -ENOMEM;
+ }

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..a24d567a6c36 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 +388,13 @@ 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);
- }
+ kfree_sensitive(op->key);
op->keylen = keylen;
op->key = kmemdup(key, keylen, GFP_KERNEL | GFP_DMA);
- if (!op->key)
+ if (unlikely(!op->key))
+ op->keylen = 0;
return -ENOMEM;
+ }

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 +413,13 @@ 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);
- }
+ kfree_sensitive(op->key);
op->keylen = keylen;
op->key = kmemdup(key, keylen, GFP_KERNEL | GFP_DMA);
- if (!op->key)
+ if (unlikely(!op->key))
+ op->keylen = 0;
return -ENOMEM;
+ }

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..5312bad7534e 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 +365,13 @@ 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);
- }
+ kfree_sensitive(op->key);
op->keylen = keylen;
op->key = kmemdup(key, keylen, GFP_KERNEL | GFP_DMA);
- if (!op->key)
+ if (unlikely(!op->key))
+ op->keylen = 0;
return -ENOMEM;
+ }

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;
--
2.18.1
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