path: root/crypto
diff options
authorDaniel Borkmann <>2014-11-19 17:13:11 +0100
committerHerbert Xu <>2014-11-25 22:50:39 +0800
commit79e886599e6416d0de26e8562e4464577d081c3d (patch)
tree83a545d589f1bb7ba5de28cc768ce549598fd0b2 /crypto
parent5d26a105b5a73e5635eae0629b42fa0a90e07b7b (diff)
crypto: algif - add and use sock_kzfree_s() instead of memzero_explicit()
Commit e1bd95bf7c25 ("crypto: algif - zeroize IV buffer") and 2a6af25befd0 ("crypto: algif - zeroize message digest buffer") added memzero_explicit() calls on buffers that are later on passed back to sock_kfree_s(). This is a discussed follow-up that, instead, extends the sock API and adds sock_kzfree_s(), which internally uses kzfree() instead of kfree() for passing the buffers back to slab. Having sock_kzfree_s() allows to keep the changes more minimal by just having a drop-in replacement instead of adding memzero_explicit() calls everywhere before sock_kfree_s(). In kzfree(), the compiler is not allowed to optimize the memset() away and thus there's no need for memzero_explicit(). Both, sock_kfree_s() and sock_kzfree_s() are wrappers for __sock_kfree_s() and call into kfree() resp. kzfree(); here, __sock_kfree_s() needs to be explicitly inlined as we want the compiler to optimize the call and condition away and thus it produces e.g. on x86_64 the _same_ assembler output for sock_kfree_s() before and after, and thus also allows for avoiding code duplication. Cc: David S. Miller <> Signed-off-by: Daniel Borkmann <> Signed-off-by: Herbert Xu <>
Diffstat (limited to 'crypto')
2 files changed, 3 insertions, 6 deletions
diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c
index f75db4ce48bf..e6050396a3b3 100644
--- a/crypto/algif_hash.c
+++ b/crypto/algif_hash.c
@@ -258,10 +258,8 @@ static void hash_sock_destruct(struct sock *sk)
struct alg_sock *ask = alg_sk(sk);
struct hash_ctx *ctx = ask->private;
- memzero_explicit(ctx->result,
- crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req)));
- sock_kfree_s(sk, ctx->result,
- crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req)));
+ sock_kzfree_s(sk, ctx->result,
+ crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req)));
sock_kfree_s(sk, ctx, ctx->len);
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 85e3bdbe214c..34389964000d 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -566,8 +566,7 @@ static void skcipher_sock_destruct(struct sock *sk)
struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(&ctx->req);
- memzero_explicit(ctx->iv, crypto_ablkcipher_ivsize(tfm));
- sock_kfree_s(sk, ctx->iv, crypto_ablkcipher_ivsize(tfm));
+ sock_kzfree_s(sk, ctx->iv, crypto_ablkcipher_ivsize(tfm));
sock_kfree_s(sk, ctx, ctx->len);