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>

2 files changed, 3 insertions, 2 deletions

diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h
index 8ed8daf7f1ee..ce7852cf526b 100644
--- a/security/selinux/include/security.h
+++ b/security/selinux/include/security.h
@@ -134,7 +134,7 @@ int security_sid_to_context(u32 sid, char **scontext,
 int security_sid_to_context_force(u32 sid, char **scontext, u32 *scontext_len);
 
 int security_context_to_sid(const char *scontext, u32 scontext_len,
-	u32 *out_sid);
+			    u32 *out_sid, gfp_t gfp);
 
 int security_context_to_sid_default(const char *scontext, u32 scontext_len,
 				    u32 *out_sid, u32 def_sid, gfp_t gfp_flags);
diff --git a/security/selinux/include/xfrm.h b/security/selinux/include/xfrm.h
index 48c3cc94c168..9f0584710c85 100644
--- a/security/selinux/include/xfrm.h
+++ b/security/selinux/include/xfrm.h
@@ -10,7 +10,8 @@
 #include <net/flow.h>
 
 int selinux_xfrm_policy_alloc(struct xfrm_sec_ctx **ctxp,
-			      struct xfrm_user_sec_ctx *uctx);
+			      struct xfrm_user_sec_ctx *uctx,
+			      gfp_t gfp);
 int selinux_xfrm_policy_clone(struct xfrm_sec_ctx *old_ctx,
 			      struct xfrm_sec_ctx **new_ctxp);
 void selinux_xfrm_policy_free(struct xfrm_sec_ctx *ctx);