net: af_key: fix sleeping under rcu

There's a kmalloc with GFP_KERNEL in a helper
(pfkey_sadb2xfrm_user_sec_ctx) used in pfkey_compile_policy which is
called under rcu_read_lock. Adjust pfkey_sadb2xfrm_user_sec_ctx to have
a gfp argument and adjust the users.

CC: Dave Jones <davej@redhat.com>
CC: Steffen Klassert <steffen.klassert@secunet.com>
CC: Fan Du <fan.du@windriver.com>
CC: David S. Miller <davem@davemloft.net>

Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

net/key/af_key.c

diff --git a/net/key/af_key.c b/net/key/af_key.c
index 1a04c13..1526023 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -433,12 +433,13 @@
 	return 0;
 }
 
-static inline struct xfrm_user_sec_ctx *pfkey_sadb2xfrm_user_sec_ctx(const struct sadb_x_sec_ctx *sec_ctx)
+static inline struct xfrm_user_sec_ctx *pfkey_sadb2xfrm_user_sec_ctx(const struct sadb_x_sec_ctx *sec_ctx,
+								     gfp_t gfp)
 {
 	struct xfrm_user_sec_ctx *uctx = NULL;
 	int ctx_size = sec_ctx->sadb_x_ctx_len;
 
-	uctx = kmalloc((sizeof(*uctx)+ctx_size), GFP_KERNEL);
+	uctx = kmalloc((sizeof(*uctx)+ctx_size), gfp);
 
 	if (!uctx)
 		return NULL;
@@ -1124,7 +1125,7 @@
 
 	sec_ctx = ext_hdrs[SADB_X_EXT_SEC_CTX - 1];
 	if (sec_ctx != NULL) {
-		struct xfrm_user_sec_ctx *uctx = pfkey_sadb2xfrm_user_sec_ctx(sec_ctx);
+		struct xfrm_user_sec_ctx *uctx = pfkey_sadb2xfrm_user_sec_ctx(sec_ctx, GFP_KERNEL);
 
 		if (!uctx)
 			goto out;
@@ -2231,7 +2232,7 @@
 
 	sec_ctx = ext_hdrs[SADB_X_EXT_SEC_CTX - 1];
 	if (sec_ctx != NULL) {
-		struct xfrm_user_sec_ctx *uctx = pfkey_sadb2xfrm_user_sec_ctx(sec_ctx);
+		struct xfrm_user_sec_ctx *uctx = pfkey_sadb2xfrm_user_sec_ctx(sec_ctx, GFP_KERNEL);
 
 		if (!uctx) {
 			err = -ENOBUFS;
@@ -2335,7 +2336,7 @@
 
 	sec_ctx = ext_hdrs[SADB_X_EXT_SEC_CTX - 1];
 	if (sec_ctx != NULL) {
-		struct xfrm_user_sec_ctx *uctx = pfkey_sadb2xfrm_user_sec_ctx(sec_ctx);
+		struct xfrm_user_sec_ctx *uctx = pfkey_sadb2xfrm_user_sec_ctx(sec_ctx, GFP_KERNEL);
 
 		if (!uctx)
 			return -ENOMEM;
@@ -3239,7 +3240,7 @@
 		}
 		if ((*dir = verify_sec_ctx_len(p)))
 			goto out;
-		uctx = pfkey_sadb2xfrm_user_sec_ctx(sec_ctx);
+		uctx = pfkey_sadb2xfrm_user_sec_ctx(sec_ctx, GFP_ATOMIC);
 		*dir = security_xfrm_policy_alloc(&xp->security, uctx);
 		kfree(uctx);