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authorAntony Antony <antony.antony@secunet.com>2020-11-17 17:47:23 +0100
committerSteffen Klassert <steffen.klassert@secunet.com>2020-11-27 11:03:06 +0100
commitc7a5899eb26e2a4d516d53f65b6dd67be2228041 (patch)
tree3c57c631ca926f27378b28bc9fa2a6f6d81476c8 /net
parent8be33ecfc1ffd2da20cc29e957e4cb6eb99310cb (diff)
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xfrm: redact SA secret with lockdown confidentiality
redact XFRM SA secret in the netlink response to xfrm_get_sa() or dumpall sa. Enable lockdown, confidentiality mode, at boot or at run time. e.g. when enabled: cat /sys/kernel/security/lockdown none integrity [confidentiality] 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 note: the aead secret is redacted. Redacting secret is also a FIPS 140-2 requirement. v1->v2 - add size checks before memset calls v2->v3 - replace spaces with tabs for consistency v3->v4 - use kernel lockdown instead of a /proc setting v4->v5 - remove kconfig option Reviewed-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Antony Antony <antony.antony@secunet.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Diffstat (limited to 'net')
-rw-r--r--net/xfrm/xfrm_user.c74
1 files changed, 67 insertions, 7 deletions
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index d0c32a8fcc4a..0727ac853b55 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -848,21 +848,84 @@ static int copy_user_offload(struct xfrm_state_offload *xso, struct sk_buff *skb
return 0;
}
+static bool xfrm_redact(void)
+{
+ return IS_ENABLED(CONFIG_SECURITY) &&
+ security_locked_down(LOCKDOWN_XFRM_SECRET);
+}
+
static int copy_to_user_auth(struct xfrm_algo_auth *auth, struct sk_buff *skb)
{
struct xfrm_algo *algo;
+ struct xfrm_algo_auth *ap;
struct nlattr *nla;
+ bool redact_secret = xfrm_redact();
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(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;
+ bool redact_secret = xfrm_redact();
+
+ 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(struct xfrm_algo *ealg, struct sk_buff *skb)
+{
+ struct xfrm_algo *ap;
+ bool redact_secret = xfrm_redact();
+ 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;
}
@@ -906,20 +969,17 @@ 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(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);
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(x->ealg, skb);
if (ret)
goto out;
}