diff options
author | Daniel Borkmann <dborkman@redhat.com> | 2014-11-19 17:13:11 +0100 |
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committer | Herbert Xu <herbert@gondor.apana.org.au> | 2014-11-25 22:50:39 +0800 |
commit | 79e886599e6416d0de26e8562e4464577d081c3d (patch) | |
tree | 83a545d589f1bb7ba5de28cc768ce549598fd0b2 /net/core/sock.c | |
parent | 5d26a105b5a73e5635eae0629b42fa0a90e07b7b (diff) | |
download | linux-79e886599e6416d0de26e8562e4464577d081c3d.tar.bz2 |
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 'net/core/sock.c')
-rw-r--r-- | net/core/sock.c | 24 |
1 files changed, 20 insertions, 4 deletions
diff --git a/net/core/sock.c b/net/core/sock.c index 15e0c67b1069..04ce26a996bd 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1713,18 +1713,34 @@ void *sock_kmalloc(struct sock *sk, int size, gfp_t priority) } EXPORT_SYMBOL(sock_kmalloc); -/* - * Free an option memory block. +/* Free an option memory block. Note, we actually want the inline + * here as this allows gcc to detect the nullify and fold away the + * condition entirely. */ -void sock_kfree_s(struct sock *sk, void *mem, int size) +static inline void __sock_kfree_s(struct sock *sk, void *mem, int size, + const bool nullify) { if (WARN_ON_ONCE(!mem)) return; - kfree(mem); + if (nullify) + kzfree(mem); + else + kfree(mem); atomic_sub(size, &sk->sk_omem_alloc); } + +void sock_kfree_s(struct sock *sk, void *mem, int size) +{ + __sock_kfree_s(sk, mem, size, false); +} EXPORT_SYMBOL(sock_kfree_s); +void sock_kzfree_s(struct sock *sk, void *mem, int size) +{ + __sock_kfree_s(sk, mem, size, true); +} +EXPORT_SYMBOL(sock_kzfree_s); + /* It is almost wait_for_tcp_memory minus release_sock/lock_sock. I think, these locks should be removed for datagram sockets. */ |