selinux: add gfp argument to security_xfrm_policy_alloc and fix callers

security_xfrm_policy_alloc can be called in atomic context so the
allocation should be done with GFP_ATOMIC. Add an argument to let the
callers choose the appropriate way. In order to do so a gfp argument
needs to be added to the method xfrm_policy_alloc_security in struct
security_operations and to the internal function
selinux_xfrm_alloc_user. After that switch to GFP_ATOMIC in the atomic
callers and leave GFP_KERNEL as before for the rest.
The path that needed the gfp argument addition is:
security_xfrm_policy_alloc -> security_ops.xfrm_policy_alloc_security ->
all users of xfrm_policy_alloc_security (e.g. selinux_xfrm_policy_alloc) ->
selinux_xfrm_alloc_user (here the allocation used to be GFP_KERNEL only)

Now adding a gfp argument to selinux_xfrm_alloc_user requires us to also
add it to security_context_to_sid which is used inside and prior to this
patch did only GFP_KERNEL allocation. So add gfp argument to
security_context_to_sid and adjust all of its callers as well.

CC: Paul Moore <paul@paul-moore.com>
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>
CC: LSM list <linux-security-module@vger.kernel.org>
CC: SELinux list <selinux@tycho.nsa.gov>

Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/security/security.c b/security/security.c
index 15b6928592ef..919cad93ac82 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1317,9 +1317,11 @@ void security_skb_owned_by(struct sk_buff *skb, struct sock *sk)
 
 #ifdef CONFIG_SECURITY_NETWORK_XFRM
 
-int security_xfrm_policy_alloc(struct xfrm_sec_ctx **ctxp, struct xfrm_user_sec_ctx *sec_ctx)
+int security_xfrm_policy_alloc(struct xfrm_sec_ctx **ctxp,
+                               struct xfrm_user_sec_ctx *sec_ctx,
+                               gfp_t gfp)
 {
-        return security_ops->xfrm_policy_alloc_security(ctxp, sec_ctx);
+        return security_ops->xfrm_policy_alloc_security(ctxp, sec_ctx, gfp);
 }
 EXPORT_SYMBOL(security_xfrm_policy_alloc);