Received-SPF: pass (google.com: domain of linux-crypto-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) client-ip=2620:137:e000::1:18;
From:   GUO Zihua <guozihua@huawei.com>
To:     <keyrings@vger.kernel.org>
CC:     <linux-crypto@vger.kernel.org>, <davem@davemloft.net>,
        <dhowells@redhat.com>, <herbert@gondor.apana.org.au>,
        <gustavoars@kernel.org>, <linux-hardening@vger.kernel.org>
Subject: [PATCH v3] crypto: Use struct_size() helper in kmalloc()
Date:   Wed, 18 May 2022 14:25:18 +0800
Message-ID: <20220518062518.236965-1-guozihua@huawei.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 7BIT
Content-Type:   text/plain; charset=US-ASCII
Precedence: bulk

Make use of struct_size() helper for structures containing flexible array
member instead of sizeof() which prevents potential issues, as well as
increase readability.

Reference: https://lore.kernel.org/all/CAHk-=wiGWjxs7EVUpccZEi6esvjpHJdgHQ=vtUeJ5crL62hx9A@mail.gmail.com/

Signed-off-by: GUO Zihua <guozihua@huawei.com>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

---

v3:
    Update commit message according to Gustavo's review.
v2:
    Use size_add() helper following Kees Cook's suggestion.
---
 crypto/asymmetric_keys/asymmetric_type.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c
index 41a2f0eb4ce4..e020222b1fe5 100644
--- a/crypto/asymmetric_keys/asymmetric_type.c
+++ b/crypto/asymmetric_keys/asymmetric_type.c
@@ -152,7 +152,7 @@ struct asymmetric_key_id *asymmetric_key_generate_id(const void *val_1,
 {
 	struct asymmetric_key_id *kid;
 
-	kid = kmalloc(sizeof(struct asymmetric_key_id) + len_1 + len_2,
+	kid = kmalloc(struct_size(kid, data, size_add(len_1, len_2)),
 		      GFP_KERNEL);
 	if (!kid)
 		return ERR_PTR(-ENOMEM);
@@ -244,7 +244,7 @@ struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id)
 	if (asciihexlen & 1)
 		return ERR_PTR(-EINVAL);
 
-	match_id = kmalloc(sizeof(struct asymmetric_key_id) + asciihexlen / 2,
+	match_id = kmalloc(struct_size(match_id, data, asciihexlen / 2),
 			   GFP_KERNEL);
 	if (!match_id)
 		return ERR_PTR(-ENOMEM);
-- 
2.36.0