pull request (net-next): ipsec-next 2020-12-12

pull request (net-next): ipsec-next 2020-12-12

[Steffen Klassert]

Just one patch this time:

1) Redact the SA keys with kernel lockdown confidentiality.
   If enabled, no secret keys are sent to uuserspace.
   From Antony Antony.

Please pull or let me know if there are problems.

Thanks!

The following changes since commit 8be33ecfc1ffd2da20cc29e957e4cb6eb99310cb:

  net: skb_vlan_untag(): don't reset transport offset if set by GRO layer (2020-11-09 20:03:55 -0800)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next.git master

for you to fetch changes up to c7a5899eb26e2a4d516d53f65b6dd67be2228041:

  xfrm: redact SA secret with lockdown confidentiality (2020-11-27 11:03:06 +0100)

----------------------------------------------------------------
Antony Antony (1):
      xfrm: redact SA secret with lockdown confidentiality

 include/linux/security.h |  1 +
 net/xfrm/xfrm_user.c     | 74 +++++++++++++++++++++++++++++++++++++++++++-----
 security/security.c      |  1 +
 3 files changed, 69 insertions(+), 7 deletions(-)

[PATCH] xfrm: redact SA secret with lockdown confidentiality

[Steffen Klassert]

From: Antony Antony <antony.antony@secunet.com>

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>
---
 include/linux/security.h |  1 +
 net/xfrm/xfrm_user.c     | 74 ++++++++++++++++++++++++++++++++++++----
 security/security.c      |  1 +
 3 files changed, 69 insertions(+), 7 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index bc2725491560..1112a79a7dba 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -127,6 +127,7 @@ enum lockdown_reason {
 	LOCKDOWN_PERF,
 	LOCKDOWN_TRACEFS,
 	LOCKDOWN_XMON_RW,
+	LOCKDOWN_XFRM_SECRET,
 	LOCKDOWN_CONFIDENTIALITY_MAX,
 };
 
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;
 	}
diff --git a/security/security.c b/security/security.c
index a28045dc9e7f..abff77c1c8a7 100644
--- a/security/security.c
+++ b/security/security.c
@@ -65,6 +65,7 @@ const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1] = {
 	[LOCKDOWN_PERF] = "unsafe use of perf",
 	[LOCKDOWN_TRACEFS] = "use of tracefs",
 	[LOCKDOWN_XMON_RW] = "xmon read and write access",
+	[LOCKDOWN_XFRM_SECRET] = "xfrm SA secret",
 	[LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality",
 };
 
-- 
2.25.1

Re: [PATCH] xfrm: redact SA secret with lockdown confidentiality

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (refs/heads/master):

On Sat, 12 Dec 2020 09:57:37 +0100 you wrote:
> From: Antony Antony <antony.antony@secunet.com>
> 
> 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]
> 
> [...]

Here is the summary with links:
  - xfrm: redact SA secret with lockdown confidentiality
    https://git.kernel.org/netdev/net-next/c/c7a5899eb26e

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

Re: pull request (net-next): ipsec-next 2020-12-12

[patchwork-bot+netdevbpf]

Hello:

This pull request was applied to netdev/net-next.git (refs/heads/master):

On Sat, 12 Dec 2020 09:57:36 +0100 you wrote:
> Just one patch this time:
> 
> 1) Redact the SA keys with kernel lockdown confidentiality.
>    If enabled, no secret keys are sent to uuserspace.
>    From Antony Antony.
> 
> Please pull or let me know if there are problems.
> 
> [...]

Here is the summary with links:
  - pull request (net-next): ipsec-next 2020-12-12
    https://git.kernel.org/netdev/net-next/c/e2437ac2f59d

You are awesome, thank you!
--
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https://korg.docs.kernel.org/patchwork/pwbot.html