diff options
| author | Daniel Borkmann | 2014-11-19 17:13:11 +0100 |
|---|---|---|
| committer | Herbert Xu | 2014-11-25 22:50:39 +0800 |
| commit | 79e886599e6416d0de26e8562e4464577d081c3d (patch) | |
| tree | 83a545d589f1bb7ba5de28cc768ce549598fd0b2 /crypto/algif_hash.c | |
| parent | 5d26a105b5a73e5635eae0629b42fa0a90e07b7b (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 <davem@davemloft.net>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto/algif_hash.c')
| -rw-r--r-- | crypto/algif_hash.c | 6 |
1 files changed, 2 insertions, 4 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); af_alg_release_parent(sk); } |