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Message-ID: <20200820183549.GA823@moon.secunet.de>
Date: Thu, 20 Aug 2020 20:35:49 +0200
From: Antony Antony <antony.antony@...unet.com>
To: Steffen Klassert <steffen.klassert@...unet.com>,
<netdev@...r.kernel.org>, Herbert Xu <herbert@...dor.apana.org.au>,
Stephan Mueller <smueller@...onox.de>
CC: Antony Antony <antony@...nome.org>,
Antony Antony <antony.antony@...unet.com>
Subject: [PATCH ipsec-next v3] xfrm: add /proc/sys/core/net/xfrm_redact_secret
when enabled, 1, redact XFRM SA secret in the netlink response to
xfrm_get_sa() or dump all sa.
e.g
echo 1 > /proc/sys/net/core/xfrm_redact_secret
ip xfrm state
src 172.16.1.200 dst 172.16.1.100
proto esp spi 0x00000002 reqid 2 mode tunnel
replay-window 0
aead rfc4106(gcm(aes)) 0x0000000000000000000000000000000000000000 96
the aead secret is redacted.
/proc/sys/core/net/xfrm_redact_secret is a toggle.
Once enabled, either at compile or via proc, it can not be disabled.
Redacting secret is a FIPS 140-2 requirement.
v1->v2
- add size checks before memset calls
v1->v3
- replace spaces with tabs for consistancy
Signed-off-by: Antony Antony <antony.antony@...unet.com>
---
Documentation/networking/xfrm_sysctl.rst | 7 +++
include/net/netns/xfrm.h | 1 +
net/xfrm/Kconfig | 10 ++++
net/xfrm/xfrm_sysctl.c | 20 +++++++
net/xfrm/xfrm_user.c | 76 +++++++++++++++++++++---
5 files changed, 105 insertions(+), 9 deletions(-)
diff --git a/Documentation/networking/xfrm_sysctl.rst b/Documentation/networking/xfrm_sysctl.rst
index 47b9bbdd0179..26432b0ff3ac 100644
--- a/Documentation/networking/xfrm_sysctl.rst
+++ b/Documentation/networking/xfrm_sysctl.rst
@@ -9,3 +9,10 @@ XFRM Syscall
xfrm_acq_expires - INTEGER
default 30 - hard timeout in seconds for acquire requests
+
+xfrm_redact_secret - INTEGER
+ A toggle to redact xfrm SA's secret to userspace.
+ When true the kernel, netlink message will redact SA secret
+ to userspace. This is part of FIPS 140-2 requirement.
+ Once the value is set to true, either at compile or at run time,
+ it can not be set to false.
diff --git a/include/net/netns/xfrm.h b/include/net/netns/xfrm.h
index 59f45b1e9dac..0ca9328daad4 100644
--- a/include/net/netns/xfrm.h
+++ b/include/net/netns/xfrm.h
@@ -64,6 +64,7 @@ struct netns_xfrm {
u32 sysctl_aevent_rseqth;
int sysctl_larval_drop;
u32 sysctl_acq_expires;
+ u32 sysctl_redact_secret;
#ifdef CONFIG_SYSCTL
struct ctl_table_header *sysctl_hdr;
#endif
diff --git a/net/xfrm/Kconfig b/net/xfrm/Kconfig
index 5b9a5ab48111..270a4e906a15 100644
--- a/net/xfrm/Kconfig
+++ b/net/xfrm/Kconfig
@@ -91,6 +91,16 @@ config XFRM_ESP
select CRYPTO_SEQIV
select CRYPTO_SHA256
+config XFRM_REDACT_SECRET
+ bool "Redact xfrm SA secret in netlink message"
+ depends on SYSCTL
+ default n
+ help
+ Enable XFRM SA secret redact in the netlink message.
+ Redacting secret is a FIPS 140-2 requirement.
+ Once enabled at compile, the value can not be set to false on
+ a running system.
+
config XFRM_IPCOMP
tristate
select XFRM_ALGO
diff --git a/net/xfrm/xfrm_sysctl.c b/net/xfrm/xfrm_sysctl.c
index 0c6c5ef65f9d..bff1f55b198e 100644
--- a/net/xfrm/xfrm_sysctl.c
+++ b/net/xfrm/xfrm_sysctl.c
@@ -4,15 +4,25 @@
#include <net/net_namespace.h>
#include <net/xfrm.h>
+#ifdef CONFIG_SYSCTL
+#ifdef CONFIG_XFRM_REDACT_SECRET
+#define XFRM_REDACT_SECRET 1
+#else
+#define XFRM_REDACT_SECRET 0
+#endif
+#endif
+
static void __net_init __xfrm_sysctl_init(struct net *net)
{
net->xfrm.sysctl_aevent_etime = XFRM_AE_ETIME;
net->xfrm.sysctl_aevent_rseqth = XFRM_AE_SEQT_SIZE;
net->xfrm.sysctl_larval_drop = 1;
net->xfrm.sysctl_acq_expires = 30;
+ net->xfrm.sysctl_redact_secret = XFRM_REDACT_SECRET;
}
#ifdef CONFIG_SYSCTL
+
static struct ctl_table xfrm_table[] = {
{
.procname = "xfrm_aevent_etime",
@@ -38,6 +48,15 @@ static struct ctl_table xfrm_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec
},
+ {
+ .procname = "xfrm_redact_secret",
+ .maxlen = sizeof(u32),
+ .mode = 0644,
+ /* only handle a transition from "0" to "1" */
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = SYSCTL_ONE,
+ .extra2 = SYSCTL_ONE,
+ },
{}
};
@@ -54,6 +73,7 @@ int __net_init xfrm_sysctl_init(struct net *net)
table[1].data = &net->xfrm.sysctl_aevent_rseqth;
table[2].data = &net->xfrm.sysctl_larval_drop;
table[3].data = &net->xfrm.sysctl_acq_expires;
+ table[4].data = &net->xfrm.sysctl_redact_secret;
/* Don't export sysctls to unprivileged users */
if (net->user_ns != &init_user_ns)
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index fbb7d9d06478..c33ebc166e04 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -848,21 +848,78 @@ static int copy_user_offload(struct xfrm_state_offload *xso, struct sk_buff *skb
return 0;
}
-static int copy_to_user_auth(struct xfrm_algo_auth *auth, struct sk_buff *skb)
+static int copy_to_user_auth(u32 redact_secret, struct xfrm_algo_auth *auth,
+ struct sk_buff *skb)
{
struct xfrm_algo *algo;
+ struct xfrm_algo_auth *ap;
struct nlattr *nla;
nla = nla_reserve(skb, XFRMA_ALG_AUTH,
sizeof(*algo) + (auth->alg_key_len + 7) / 8);
if (!nla)
return -EMSGSIZE;
-
algo = nla_data(nla);
strncpy(algo->alg_name, auth->alg_name, sizeof(algo->alg_name));
- memcpy(algo->alg_key, auth->alg_key, (auth->alg_key_len + 7) / 8);
+
+ if (redact_secret && auth->alg_key_len)
+ memset(algo->alg_key, 0, (auth->alg_key_len + 7) / 8);
+ else
+ memcpy(algo->alg_key, auth->alg_key,
+ (auth->alg_key_len + 7) / 8);
algo->alg_key_len = auth->alg_key_len;
+ nla = nla_reserve(skb, XFRMA_ALG_AUTH_TRUNC, xfrm_alg_auth_len(auth));
+ if (!nla)
+ return -EMSGSIZE;
+ ap = nla_data(nla);
+ memcpy(ap, auth, sizeof(struct xfrm_algo_auth));
+ if (redact_secret && auth->alg_key_len)
+ memset(ap->alg_key, 0, (auth->alg_key_len + 7) / 8);
+ else
+ memcpy(ap->alg_key, auth->alg_key,
+ (auth->alg_key_len + 7) / 8);
+ return 0;
+}
+
+static int copy_to_user_aead(u32 redact_secret,
+ struct xfrm_algo_aead *aead, struct sk_buff *skb)
+{
+ struct nlattr *nla = nla_reserve(skb, XFRMA_ALG_AEAD, aead_len(aead));
+ struct xfrm_algo_aead *ap;
+
+ if (!nla)
+ return -EMSGSIZE;
+
+ ap = nla_data(nla);
+ memcpy(ap, aead, sizeof(*aead));
+
+ if (redact_secret && aead->alg_key_len)
+ memset(ap->alg_key, 0, (aead->alg_key_len + 7) / 8);
+ else
+ memcpy(ap->alg_key, aead->alg_key,
+ (aead->alg_key_len + 7) / 8);
+ return 0;
+}
+
+static int copy_to_user_ealg(u32 redact_secret, struct xfrm_algo *ealg,
+ struct sk_buff *skb)
+{
+ struct xfrm_algo *ap;
+ struct nlattr *nla = nla_reserve(skb, XFRMA_ALG_CRYPT,
+ xfrm_alg_len(ealg));
+ if (!nla)
+ return -EMSGSIZE;
+
+ ap = nla_data(nla);
+ memcpy(ap, ealg, sizeof(*ealg));
+
+ if (redact_secret && ealg->alg_key_len)
+ memset(ap->alg_key, 0, (ealg->alg_key_len + 7) / 8);
+ else
+ memcpy(ap->alg_key, ealg->alg_key,
+ (ealg->alg_key_len + 7) / 8);
+
return 0;
}
@@ -884,6 +941,7 @@ static int copy_to_user_state_extra(struct xfrm_state *x,
struct sk_buff *skb)
{
int ret = 0;
+ struct net *net = xs_net(x);
copy_to_user_state(x, p);
@@ -906,20 +964,20 @@ static int copy_to_user_state_extra(struct xfrm_state *x,
goto out;
}
if (x->aead) {
- ret = nla_put(skb, XFRMA_ALG_AEAD, aead_len(x->aead), x->aead);
+ ret = copy_to_user_aead(net->xfrm.sysctl_redact_secret,
+ x->aead, skb);
if (ret)
goto out;
}
if (x->aalg) {
- ret = copy_to_user_auth(x->aalg, skb);
- if (!ret)
- ret = nla_put(skb, XFRMA_ALG_AUTH_TRUNC,
- xfrm_alg_auth_len(x->aalg), x->aalg);
+ ret = copy_to_user_auth(net->xfrm.sysctl_redact_secret,
+ x->aalg, skb);
if (ret)
goto out;
}
if (x->ealg) {
- ret = nla_put(skb, XFRMA_ALG_CRYPT, xfrm_alg_len(x->ealg), x->ealg);
+ ret = copy_to_user_ealg(net->xfrm.sysctl_redact_secret,
+ x->ealg, skb);
if (ret)
goto out;
}
--
2.20.1
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