Re: [PATCH] crypto: using size_add() for kmalloc()

[Christophe JAILLET]

Le 21/04/2025 à 07:51, Su Hui a écrit :

It's safer to use size_add() to replace open-coded aithmetic in allocator
arguments, because size_add() can prevent possible overflow problem.

Signed-off-by: Su Hui <su...@nfschina.com>
---
  include/crypto/aead.h     | 3 ++-
  include/crypto/akcipher.h | 4 +++-
  include/crypto/kpp.h      | 3 ++-
  3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/include/crypto/aead.h b/include/crypto/aead.h
index 0e8a41638678..cf212d28fe18 100644
--- a/include/crypto/aead.h
+++ b/include/crypto/aead.h
@@ -10,6 +10,7 @@

#include <linux/atomic.h>

  #include <linux/container_of.h>
+#include <linux/overflow.h>

You could move this 1 line below, to keep alphabetical order.
And why do you say that it is redundant in your follow-up mail?

  #include <linux/crypto.h>
  #include <linux/slab.h>
  #include <linux/types.h>
@@ -433,7 +434,7 @@ static inline struct aead_request 
*aead_request_alloc(struct crypto_aead *tfm,
  {
        struct aead_request *req;

- req = kmalloc(sizeof(*req) + crypto_aead_reqsize(tfm), gfp);

+       req = kmalloc(size_add(sizeof(*req), crypto_aead_reqsize(tfm)), gfp);

if (likely(req))

                aead_request_set_tfm(req, tfm);
diff --git a/include/crypto/akcipher.h b/include/crypto/akcipher.h
index cdf7da74bf2f..4c37a602cce5 100644
--- a/include/crypto/akcipher.h
+++ b/include/crypto/akcipher.h
@@ -10,6 +10,7 @@

#include <linux/atomic.h>

  #include <linux/crypto.h>
+#include <linux/overflow.h>

/**

   * struct akcipher_request - public key cipher request
@@ -184,7 +185,8 @@ static inline struct akcipher_request 
*akcipher_request_alloc(
  {
        struct akcipher_request *req;

- req = kmalloc(sizeof(*req) + crypto_akcipher_reqsize(tfm), gfp);

+       req = kmalloc(size_add(sizeof(*req),
+                              crypto_akcipher_reqsize(tfm)), gfp);
        if (likely(req))
                akcipher_request_set_tfm(req, tfm);

diff --git a/include/crypto/kpp.h b/include/crypto/kpp.h

index 2d9c4de57b69..11ae1ad41d2a 100644
--- a/include/crypto/kpp.h
+++ b/include/crypto/kpp.h
@@ -11,6 +11,7 @@

#include <linux/atomic.h>

  #include <linux/container_of.h>
+#include <linux/overflow.h>

You could move this 1 line below, to keep alphabetical order.

  #include <linux/crypto.h>
  #include <linux/slab.h>

@@ -182,7 +183,7 @@ static inline struct kpp_request *kpp_request_alloc(struct crypto_kpp *tfm,

  {
        struct kpp_request *req;

- req = kmalloc(sizeof(*req) + crypto_kpp_reqsize(tfm), gfp);

+       req = kmalloc(size_add(sizeof(*req), crypto_kpp_reqsize(tfm)), gfp);
        if (likely(req))
                kpp_request_set_tfm(req, tfm);