Re: [PATCH 2/2] crypto: Remove unnecessary memzero_explicit()
From: Joe Perches <joe@perches.com>
Date: 2020-04-13 21:33:55
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On Mon, 2020-04-13 at 17:15 -0400, Waiman Long wrote:
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.
2 bits of trivia:
quoted hunk ↗ jump to hunk
diff --git a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-cipher.c b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-cipher.c
[]
quoted hunk ↗ jump to hunk
@@ -391,10 +388,7 @@ 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)
It might be a defect to set op->keylen before the kmemdup succeeds.
quoted hunk ↗ jump to hunk
@@ -416,10 +410,7 @@ 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); - } + free_sensitive(op->key, op->keylen);
Why not kfree_sensitive(op->key) ?