Merge branch 'xfrm: add netlink extack to all the ->init_stat'

Sabrina Dubroca says:

============
This series completes extack support for state creation.
============

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

13 files changed, 140 insertions, 87 deletions

diff --git a/include/net/ipcomp.h b/include/net/ipcomp.h
index c31108295079..8660a2a6d1fc 100644
--- a/include/net/ipcomp.h
+++ b/include/net/ipcomp.h
@@ -22,7 +22,7 @@ struct xfrm_state;
 int ipcomp_input(struct xfrm_state *x, struct sk_buff *skb);
 int ipcomp_output(struct xfrm_state *x, struct sk_buff *skb);
 void ipcomp_destroy(struct xfrm_state *x);
-int ipcomp_init_state(struct xfrm_state *x);
+int ipcomp_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack);
 
 static inline struct ip_comp_hdr *ip_comp_hdr(const struct sk_buff *skb)
 {
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index c504d07bcb7c..dbc81f5eb553 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -405,7 +405,8 @@ struct xfrm_type {
 #define XFRM_TYPE_LOCAL_COADDR	4
 #define XFRM_TYPE_REMOTE_COADDR	8
 
-	int			(*init_state)(struct xfrm_state *x);
+	int			(*init_state)(struct xfrm_state *x,
+					      struct netlink_ext_ack *extack);
 	void			(*destructor)(struct xfrm_state *);
 	int			(*input)(struct xfrm_state *, struct sk_buff *skb);
 	int			(*output)(struct xfrm_state *, struct sk_buff *pskb);
diff --git a/net/ipv4/ah4.c b/net/ipv4/ah4.c
index f8ad04470d3a..ee4e578c7f20 100644
--- a/net/ipv4/ah4.c
+++ b/net/ipv4/ah4.c
@@ -471,30 +471,38 @@ static int ah4_err(struct sk_buff *skb, u32 info)
 	return 0;
 }
 
-static int ah_init_state(struct xfrm_state *x)
+static int ah_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
 {
 	struct ah_data *ahp = NULL;
 	struct xfrm_algo_desc *aalg_desc;
 	struct crypto_ahash *ahash;
 
-	if (!x->aalg)
+	if (!x->aalg) {
+		NL_SET_ERR_MSG(extack, "AH requires a state with an AUTH algorithm");
 		goto error;
+	}
 
-	if (x->encap)
+	if (x->encap) {
+		NL_SET_ERR_MSG(extack, "AH is not compatible with encapsulation");
 		goto error;
+	}
 
 	ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
 	if (!ahp)
 		return -ENOMEM;
 
 	ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
-	if (IS_ERR(ahash))
+	if (IS_ERR(ahash)) {
+		NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
 		goto error;
+	}
 
 	ahp->ahash = ahash;
 	if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
-				(x->aalg->alg_key_len + 7) / 8))
+				(x->aalg->alg_key_len + 7) / 8)) {
+		NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
 		goto error;
+	}
 
 	/*
 	 * Lookup the algorithm description maintained by xfrm_algo,
@@ -507,10 +515,7 @@ static int ah_init_state(struct xfrm_state *x)
 
 	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
 	    crypto_ahash_digestsize(ahash)) {
-		pr_info("%s: %s digestsize %u != %u\n",
-			__func__, x->aalg->alg_name,
-			crypto_ahash_digestsize(ahash),
-			aalg_desc->uinfo.auth.icv_fullbits / 8);
+		NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
 		goto error;
 	}
 
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index 5c03eba787e5..751a05276f48 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -1007,16 +1007,17 @@ static void esp_destroy(struct xfrm_state *x)
 	crypto_free_aead(aead);
 }
 
-static int esp_init_aead(struct xfrm_state *x)
+static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack)
 {
 	char aead_name[CRYPTO_MAX_ALG_NAME];
 	struct crypto_aead *aead;
 	int err;
 
-	err = -ENAMETOOLONG;
 	if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
-		     x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME)
-		goto error;
+		     x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) {
+		NL_SET_ERR_MSG(extack, "Algorithm name is too long");
+		return -ENAMETOOLONG;
+	}
 
 	aead = crypto_alloc_aead(aead_name, 0, 0);
 	err = PTR_ERR(aead);
@@ -1034,11 +1035,15 @@ static int esp_init_aead(struct xfrm_state *x)
 	if (err)
 		goto error;
 
+	return 0;
+
 error:
+	NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
 	return err;
 }
 
-static int esp_init_authenc(struct xfrm_state *x)
+static int esp_init_authenc(struct xfrm_state *x,
+			    struct netlink_ext_ack *extack)
 {
 	struct crypto_aead *aead;
 	struct crypto_authenc_key_param *param;
@@ -1049,10 +1054,6 @@ static int esp_init_authenc(struct xfrm_state *x)
 	unsigned int keylen;
 	int err;
 
-	err = -EINVAL;
-	if (!x->ealg)
-		goto error;
-
 	err = -ENAMETOOLONG;
 
 	if ((x->props.flags & XFRM_STATE_ESN)) {
@@ -1061,22 +1062,28 @@ static int esp_init_authenc(struct xfrm_state *x)
 			     x->geniv ?: "", x->geniv ? "(" : "",
 			     x->aalg ? x->aalg->alg_name : "digest_null",
 			     x->ealg->alg_name,
-			     x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
+			     x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
+			NL_SET_ERR_MSG(extack, "Algorithm name is too long");
 			goto error;
+		}
 	} else {
 		if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
 			     "%s%sauthenc(%s,%s)%s",
 			     x->geniv ?: "", x->geniv ? "(" : "",
 			     x->aalg ? x->aalg->alg_name : "digest_null",
 			     x->ealg->alg_name,
-			     x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
+			     x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
+			NL_SET_ERR_MSG(extack, "Algorithm name is too long");
 			goto error;
+		}
 	}
 
 	aead = crypto_alloc_aead(authenc_name, 0, 0);
 	err = PTR_ERR(aead);
-	if (IS_ERR(aead))
+	if (IS_ERR(aead)) {
+		NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
 		goto error;
+	}
 
 	x->data = aead;
 
@@ -1106,17 +1113,16 @@ static int esp_init_authenc(struct xfrm_state *x)
 		err = -EINVAL;
 		if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
 		    crypto_aead_authsize(aead)) {
-			pr_info("ESP: %s digestsize %u != %u\n",
-				x->aalg->alg_name,
-				crypto_aead_authsize(aead),
-				aalg_desc->uinfo.auth.icv_fullbits / 8);
+			NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
 			goto free_key;
 		}
 
 		err = crypto_aead_setauthsize(
 			aead, x->aalg->alg_trunc_len / 8);
-		if (err)
+		if (err) {
+			NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
 			goto free_key;
+		}
 	}
 
 	param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
@@ -1131,7 +1137,7 @@ error:
 	return err;
 }
 
-static int esp_init_state(struct xfrm_state *x)
+static int esp_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
 {
 	struct crypto_aead *aead;
 	u32 align;
@@ -1139,10 +1145,14 @@ static int esp_init_state(struct xfrm_state *x)
 
 	x->data = NULL;
 
-	if (x->aead)
-		err = esp_init_aead(x);
-	else
-		err = esp_init_authenc(x);
+	if (x->aead) {
+		err = esp_init_aead(x, extack);
+	} else if (x->ealg) {
+		err = esp_init_authenc(x, extack);
+	} else {
+		NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided");
+		err = -EINVAL;
+	}
 
 	if (err)
 		goto error;
@@ -1160,6 +1170,7 @@ static int esp_init_state(struct xfrm_state *x)
 
 		switch (encap->encap_type) {
 		default:
+			NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP");
 			err = -EINVAL;
 			goto error;
 		case UDP_ENCAP_ESPINUDP:
diff --git a/net/ipv4/ipcomp.c b/net/ipv4/ipcomp.c
index 366094c1ce6c..5a4fb2539b08 100644
--- a/net/ipv4/ipcomp.c
+++ b/net/ipv4/ipcomp.c
@@ -117,7 +117,8 @@ out:
 	return err;
 }
 
-static int ipcomp4_init_state(struct xfrm_state *x)
+static int ipcomp4_init_state(struct xfrm_state *x,
+			      struct netlink_ext_ack *extack)
 {
 	int err = -EINVAL;
 
@@ -129,17 +130,20 @@ static int ipcomp4_init_state(struct xfrm_state *x)
 		x->props.header_len += sizeof(struct iphdr);
 		break;
 	default:
+		NL_SET_ERR_MSG(extack, "Unsupported XFRM mode for IPcomp");
 		goto out;
 	}
 
-	err = ipcomp_init_state(x);
+	err = ipcomp_init_state(x, extack);
 	if (err)
 		goto out;
 
 	if (x->props.mode == XFRM_MODE_TUNNEL) {
 		err = ipcomp_tunnel_attach(x);
-		if (err)
+		if (err) {
+			NL_SET_ERR_MSG(extack, "Kernel error: failed to initialize the associated state");
 			goto out;
+		}
 	}
 
 	err = 0;
diff --git a/net/ipv4/xfrm4_tunnel.c b/net/ipv4/xfrm4_tunnel.c
index 9d4f418f1bf8..8489fa106583 100644
--- a/net/ipv4/xfrm4_tunnel.c
+++ b/net/ipv4/xfrm4_tunnel.c
@@ -22,13 +22,17 @@ static int ipip_xfrm_rcv(struct xfrm_state *x, struct sk_buff *skb)
 	return ip_hdr(skb)->protocol;
 }
 
-static int ipip_init_state(struct xfrm_state *x)
+static int ipip_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
 {
-	if (x->props.mode != XFRM_MODE_TUNNEL)
+	if (x->props.mode != XFRM_MODE_TUNNEL) {
+		NL_SET_ERR_MSG(extack, "IPv4 tunnel can only be used with tunnel mode");
 		return -EINVAL;
+	}
 
-	if (x->encap)
+	if (x->encap) {
+		NL_SET_ERR_MSG(extack, "IPv4 tunnel is not compatible with encapsulation");
 		return -EINVAL;
+	}
 
 	x->props.header_len = sizeof(struct iphdr);
 
diff --git a/net/ipv6/ah6.c b/net/ipv6/ah6.c
index b5995c1f4d7a..5228d2716289 100644
--- a/net/ipv6/ah6.c
+++ b/net/ipv6/ah6.c
@@ -666,30 +666,38 @@ static int ah6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	return 0;
 }
 
-static int ah6_init_state(struct xfrm_state *x)
+static int ah6_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
 {
 	struct ah_data *ahp = NULL;
 	struct xfrm_algo_desc *aalg_desc;
 	struct crypto_ahash *ahash;
 
-	if (!x->aalg)
+	if (!x->aalg) {
+		NL_SET_ERR_MSG(extack, "AH requires a state with an AUTH algorithm");
 		goto error;
+	}
 
-	if (x->encap)
+	if (x->encap) {
+		NL_SET_ERR_MSG(extack, "AH is not compatible with encapsulation");
 		goto error;
+	}
 
 	ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
 	if (!ahp)
 		return -ENOMEM;
 
 	ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
-	if (IS_ERR(ahash))
+	if (IS_ERR(ahash)) {
+		NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
 		goto error;
+	}
 
 	ahp->ahash = ahash;
 	if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
-			       (x->aalg->alg_key_len + 7) / 8))
+			       (x->aalg->alg_key_len + 7) / 8)) {
+		NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
 		goto error;
+	}
 
 	/*
 	 * Lookup the algorithm description maintained by xfrm_algo,
@@ -702,9 +710,7 @@ static int ah6_init_state(struct xfrm_state *x)
 
 	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
 	    crypto_ahash_digestsize(ahash)) {
-		pr_info("AH: %s digestsize %u != %u\n",
-			x->aalg->alg_name, crypto_ahash_digestsize(ahash),
-			aalg_desc->uinfo.auth.icv_fullbits/8);
+		NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
 		goto error;
 	}
 
@@ -721,6 +727,7 @@ static int ah6_init_state(struct xfrm_state *x)
 		x->props.header_len += sizeof(struct ipv6hdr);
 		break;
 	default:
+		NL_SET_ERR_MSG(extack, "Invalid mode requested for AH, must be one of TRANSPORT, TUNNEL, BEET");
 		goto error;
 	}
 	x->data = ahp;
diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c
index 8220923a12f7..e7a16f9643e5 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -1050,16 +1050,17 @@ static void esp6_destroy(struct xfrm_state *x)
 	crypto_free_aead(aead);
 }
 
-static int esp_init_aead(struct xfrm_state *x)
+static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack)
 {
 	char aead_name[CRYPTO_MAX_ALG_NAME];
 	struct crypto_aead *aead;
 	int err;
 
-	err = -ENAMETOOLONG;
 	if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
-		     x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME)
-		goto error;
+		     x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) {
+		NL_SET_ERR_MSG(extack, "Algorithm name is too long");
+		return -ENAMETOOLONG;
+	}
 
 	aead = crypto_alloc_aead(aead_name, 0, 0);
 	err = PTR_ERR(aead);
@@ -1077,11 +1078,15 @@ static int esp_init_aead(struct xfrm_state *x)
 	if (err)
 		goto error;
 
+	return 0;
+
 error:
+	NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
 	return err;
 }
 
-static int esp_init_authenc(struct xfrm_state *x)
+static int esp_init_authenc(struct xfrm_state *x,
+			    struct netlink_ext_ack *extack)
 {
 	struct crypto_aead *aead;
 	struct crypto_authenc_key_param *param;
@@ -1092,10 +1097,6 @@ static int esp_init_authenc(struct xfrm_state *x)
 	unsigned int keylen;
 	int err;
 
-	err = -EINVAL;
-	if (!x->ealg)
-		goto error;
-
 	err = -ENAMETOOLONG;
 
 	if ((x->props.flags & XFRM_STATE_ESN)) {
@@ -1104,22 +1105,28 @@ static int esp_init_authenc(struct xfrm_state *x)
 			     x->geniv ?: "", x->geniv ? "(" : "",
 			     x->aalg ? x->aalg->alg_name : "digest_null",
 			     x->ealg->alg_name,
-			     x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
+			     x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
+			NL_SET_ERR_MSG(extack, "Algorithm name is too long");
 			goto error;
+		}
 	} else {
 		if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
 			     "%s%sauthenc(%s,%s)%s",
 			     x->geniv ?: "", x->geniv ? "(" : "",
 			     x->aalg ? x->aalg->alg_name : "digest_null",
 			     x->ealg->alg_name,
-			     x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
+			     x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
+			NL_SET_ERR_MSG(extack, "Algorithm name is too long");
 			goto error;
+		}
 	}
 
 	aead = crypto_alloc_aead(authenc_name, 0, 0);
 	err = PTR_ERR(aead);
-	if (IS_ERR(aead))
+	if (IS_ERR(aead)) {
+		NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
 		goto error;
+	}
 
 	x->data = aead;
 
@@ -1149,17 +1156,16 @@ static int esp_init_authenc(struct xfrm_state *x)
 		err = -EINVAL;
 		if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
 		    crypto_aead_authsize(aead)) {
-			pr_info("ESP: %s digestsize %u != %u\n",
-				x->aalg->alg_name,
-				crypto_aead_authsize(aead),
-				aalg_desc->uinfo.auth.icv_fullbits / 8);
+			NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
 			goto free_key;
 		}
 
 		err = crypto_aead_setauthsize(
 			aead, x->aalg->alg_trunc_len / 8);
-		if (err)
+		if (err) {
+			NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
 			goto free_key;
+		}
 	}
 
 	param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
@@ -1174,7 +1180,7 @@ error:
 	return err;
 }
 
-static int esp6_init_state(struct xfrm_state *x)
+static int esp6_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
 {
 	struct crypto_aead *aead;
 	u32 align;
@@ -1182,10 +1188,14 @@ static int esp6_init_state(struct xfrm_state *x)
 
 	x->data = NULL;
 
-	if (x->aead)
-		err = esp_init_aead(x);
-	else
-		err = esp_init_authenc(x);
+	if (x->aead) {
+		err = esp_init_aead(x, extack);
+	} else if (x->ealg) {
+		err = esp_init_authenc(x, extack);
+	} else {
+		NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided");
+		err = -EINVAL;
+	}
 
 	if (err)
 		goto error;
@@ -1213,6 +1223,7 @@ static int esp6_init_state(struct xfrm_state *x)
 
 		switch (encap->encap_type) {
 		default:
+			NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP");
 			err = -EINVAL;
 			goto error;
 		case UDP_ENCAP_ESPINUDP:
diff --git a/net/ipv6/ipcomp6.c b/net/ipv6/ipcomp6.c
index 15f984be3570..72d4858dec18 100644
--- a/net/ipv6/ipcomp6.c
+++ b/net/ipv6/ipcomp6.c
@@ -136,7 +136,8 @@ out:
 	return err;
 }
 
-static int ipcomp6_init_state(struct xfrm_state *x)
+static int ipcomp6_init_state(struct xfrm_state *x,
+			      struct netlink_ext_ack *extack)
 {
 	int err = -EINVAL;
 
@@ -148,17 +149,20 @@ static int ipcomp6_init_state(struct xfrm_state *x)
 		x->props.header_len += sizeof(struct ipv6hdr);
 		break;
 	default:
+		NL_SET_ERR_MSG(extack, "Unsupported XFRM mode for IPcomp");
 		goto out;
 	}
 
-	err = ipcomp_init_state(x);
+	err = ipcomp_init_state(x, extack);
 	if (err)
 		goto out;
 
 	if (x->props.mode == XFRM_MODE_TUNNEL) {
 		err = ipcomp6_tunnel_attach(x);
-		if (err)
+		if (err) {
+			NL_SET_ERR_MSG(extack, "Kernel error: failed to initialize the associated state");
 			goto out;
+		}
 	}
 
 	err = 0;
diff --git a/net/ipv6/mip6.c b/net/ipv6/mip6.c
index aeb35d26e474..83d2a8be263f 100644
--- a/net/ipv6/mip6.c
+++ b/net/ipv6/mip6.c
@@ -247,15 +247,14 @@ static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb,
 	return err;
 }
 
-static int mip6_destopt_init_state(struct xfrm_state *x)
+static int mip6_destopt_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
 {
 	if (x->id.spi) {
-		pr_info("%s: spi is not 0: %u\n", __func__, x->id.spi);
+		NL_SET_ERR_MSG(extack, "SPI must be 0");
 		return -EINVAL;
 	}
 	if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
-		pr_info("%s: state's mode is not %u: %u\n",
-			__func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
+		NL_SET_ERR_MSG(extack, "XFRM mode must be XFRM_MODE_ROUTEOPTIMIZATION");
 		return -EINVAL;
 	}
 
@@ -333,15 +332,14 @@ static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb)
 	return 0;
 }
 
-static int mip6_rthdr_init_state(struct xfrm_state *x)
+static int mip6_rthdr_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
 {
 	if (x->id.spi) {
-		pr_info("%s: spi is not 0: %u\n", __func__, x->id.spi);
+		NL_SET_ERR_MSG(extack, "SPI must be 0");
 		return -EINVAL;
 	}
 	if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
-		pr_info("%s: state's mode is not %u: %u\n",
-			__func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
+		NL_SET_ERR_MSG(extack, "XFRM mode must be XFRM_MODE_ROUTEOPTIMIZATION");
 		return -EINVAL;
 	}
 
diff --git a/net/ipv6/xfrm6_tunnel.c b/net/ipv6/xfrm6_tunnel.c
index 2b31112c0856..1323f2f6928e 100644
--- a/net/ipv6/xfrm6_tunnel.c
+++ b/net/ipv6/xfrm6_tunnel.c
@@ -270,13 +270,17 @@ static int xfrm6_tunnel_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	return 0;
 }
 
-static int xfrm6_tunnel_init_state(struct xfrm_state *x)
+static int xfrm6_tunnel_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
 {
-	if (x->props.mode != XFRM_MODE_TUNNEL)
+	if (x->props.mode != XFRM_MODE_TUNNEL) {
+		NL_SET_ERR_MSG(extack, "IPv6 tunnel can only be used with tunnel mode");
 		return -EINVAL;
+	}
 
-	if (x->encap)
+	if (x->encap) {
+		NL_SET_ERR_MSG(extack, "IPv6 tunnel is not compatible with encapsulation");
 		return -EINVAL;
+	}
 
 	x->props.header_len = sizeof(struct ipv6hdr);
 
diff --git a/net/xfrm/xfrm_ipcomp.c b/net/xfrm/xfrm_ipcomp.c
index cb40ff0ff28d..656045a87606 100644
--- a/net/xfrm/xfrm_ipcomp.c
+++ b/net/xfrm/xfrm_ipcomp.c
@@ -325,18 +325,22 @@ void ipcomp_destroy(struct xfrm_state *x)
 }
 EXPORT_SYMBOL_GPL(ipcomp_destroy);
 
-int ipcomp_init_state(struct xfrm_state *x)
+int ipcomp_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
 {
 	int err;
 	struct ipcomp_data *ipcd;
 	struct xfrm_algo_desc *calg_desc;
 
 	err = -EINVAL;
-	if (!x->calg)
+	if (!x->calg) {
+		NL_SET_ERR_MSG(extack, "Missing required compression algorithm");
 		goto out;
+	}
 
-	if (x->encap)
+	if (x->encap) {
+		NL_SET_ERR_MSG(extack, "IPComp is not compatible with encapsulation");
 		goto out;
+	}
 
 	err = -ENOMEM;
 	ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 0b59ff7985e6..82c571d07836 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -2673,7 +2673,7 @@ int __xfrm_init_state(struct xfrm_state *x, bool init_replay, bool offload,
 
 	x->type_offload = xfrm_get_type_offload(x->id.proto, family, offload);
 
-	err = x->type->init_state(x);
+	err = x->type->init_state(x, extack);
 	if (err)
 		goto error;