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>

6 files changed, 40 insertions, 26 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 4b34847208cc..b332e2cc0954 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -668,7 +668,7 @@ static int selinux_set_mnt_opts(struct super_block *sb,
 		if (flags[i] == SBLABEL_MNT)
 			continue;
 		rc = security_context_to_sid(mount_options[i],
-					     strlen(mount_options[i]), &sid);
+					     strlen(mount_options[i]), &sid, GFP_KERNEL);
 		if (rc) {
 			printk(KERN_WARNING "SELinux: security_context_to_sid"
 			       "(%s) failed for (dev %s, type %s) errno=%d\n",
@@ -2489,7 +2489,8 @@ static int selinux_sb_remount(struct super_block *sb, void *data)
 		if (flags[i] == SBLABEL_MNT)
 			continue;
 		len = strlen(mount_options[i]);
-		rc = security_context_to_sid(mount_options[i], len, &sid);
+		rc = security_context_to_sid(mount_options[i], len, &sid,
+					     GFP_KERNEL);
 		if (rc) {
 			printk(KERN_WARNING "SELinux: security_context_to_sid"
 			       "(%s) failed for (dev %s, type %s) errno=%d\n",
@@ -2893,7 +2894,7 @@ static int selinux_inode_setxattr(struct dentry *dentry, const char *name,
 	if (rc)
 		return rc;
 
-	rc = security_context_to_sid(value, size, &newsid);
+	rc = security_context_to_sid(value, size, &newsid, GFP_KERNEL);
 	if (rc == -EINVAL) {
 		if (!capable(CAP_MAC_ADMIN)) {
 			struct audit_buffer *ab;
@@ -3050,7 +3051,7 @@ static int selinux_inode_setsecurity(struct inode *inode, const char *name,
 	if (!value || !size)
 		return -EACCES;
 
-	rc = security_context_to_sid((void *)value, size, &newsid);
+	rc = security_context_to_sid((void *)value, size, &newsid, GFP_KERNEL);
 	if (rc)
 		return rc;
 
@@ -5529,7 +5530,7 @@ static int selinux_setprocattr(struct task_struct *p,
 			str[size-1] = 0;
 			size--;
 		}
-		error = security_context_to_sid(value, size, &sid);
+		error = security_context_to_sid(value, size, &sid, GFP_KERNEL);
 		if (error == -EINVAL && !strcmp(name, "fscreate")) {
 			if (!capable(CAP_MAC_ADMIN)) {
 				struct audit_buffer *ab;
@@ -5638,7 +5639,7 @@ static int selinux_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
 
 static int selinux_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
 {
-	return security_context_to_sid(secdata, seclen, secid);
+	return security_context_to_sid(secdata, seclen, secid, GFP_KERNEL);
 }
 
 static void selinux_release_secctx(char *secdata, u32 seclen)
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);
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index 5122affe06a8..d60c0ee66387 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -576,7 +576,7 @@ static ssize_t sel_write_context(struct file *file, char *buf, size_t size)
 	if (length)
 		goto out;
 
-	length = security_context_to_sid(buf, size, &sid);
+	length = security_context_to_sid(buf, size, &sid, GFP_KERNEL);
 	if (length)
 		goto out;
 
@@ -731,11 +731,13 @@ static ssize_t sel_write_access(struct file *file, char *buf, size_t size)
 	if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3)
 		goto out;
 
-	length = security_context_to_sid(scon, strlen(scon) + 1, &ssid);
+	length = security_context_to_sid(scon, strlen(scon) + 1, &ssid,
+					 GFP_KERNEL);
 	if (length)
 		goto out;
 
-	length = security_context_to_sid(tcon, strlen(tcon) + 1, &tsid);
+	length = security_context_to_sid(tcon, strlen(tcon) + 1, &tsid,
+					 GFP_KERNEL);
 	if (length)
 		goto out;
 
@@ -817,11 +819,13 @@ static ssize_t sel_write_create(struct file *file, char *buf, size_t size)
 		objname = namebuf;
 	}
 
-	length = security_context_to_sid(scon, strlen(scon) + 1, &ssid);
+	length = security_context_to_sid(scon, strlen(scon) + 1, &ssid,
+					 GFP_KERNEL);
 	if (length)
 		goto out;
 
-	length = security_context_to_sid(tcon, strlen(tcon) + 1, &tsid);
+	length = security_context_to_sid(tcon, strlen(tcon) + 1, &tsid,
+					 GFP_KERNEL);
 	if (length)
 		goto out;
 
@@ -878,11 +882,13 @@ static ssize_t sel_write_relabel(struct file *file, char *buf, size_t size)
 	if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3)
 		goto out;
 
-	length = security_context_to_sid(scon, strlen(scon) + 1, &ssid);
+	length = security_context_to_sid(scon, strlen(scon) + 1, &ssid,
+					 GFP_KERNEL);
 	if (length)
 		goto out;
 
-	length = security_context_to_sid(tcon, strlen(tcon) + 1, &tsid);
+	length = security_context_to_sid(tcon, strlen(tcon) + 1, &tsid,
+					 GFP_KERNEL);
 	if (length)
 		goto out;
 
@@ -934,7 +940,7 @@ static ssize_t sel_write_user(struct file *file, char *buf, size_t size)
 	if (sscanf(buf, "%s %s", con, user) != 2)
 		goto out;
 
-	length = security_context_to_sid(con, strlen(con) + 1, &sid);
+	length = security_context_to_sid(con, strlen(con) + 1, &sid, GFP_KERNEL);
 	if (length)
 		goto out;
 
@@ -994,11 +1000,13 @@ static ssize_t sel_write_member(struct file *file, char *buf, size_t size)
 	if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3)
 		goto out;
 
-	length = security_context_to_sid(scon, strlen(scon) + 1, &ssid);
+	length = security_context_to_sid(scon, strlen(scon) + 1, &ssid,
+					 GFP_KERNEL);
 	if (length)
 		goto out;
 
-	length = security_context_to_sid(tcon, strlen(tcon) + 1, &tsid);
+	length = security_context_to_sid(tcon, strlen(tcon) + 1, &tsid,
+					 GFP_KERNEL);
 	if (length)
 		goto out;
 
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 5d0144ee8ed6..4bca49414a40 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -1289,16 +1289,18 @@ out:
  * @scontext: security context
  * @scontext_len: length in bytes
  * @sid: security identifier, SID
+ * @gfp: context for the allocation
  *
  * Obtains a SID associated with the security context that
  * has the string representation specified by @scontext.
  * Returns -%EINVAL if the context is invalid, -%ENOMEM if insufficient
  * memory is available, or 0 on success.
  */
-int security_context_to_sid(const char *scontext, u32 scontext_len, u32 *sid)
+int security_context_to_sid(const char *scontext, u32 scontext_len, u32 *sid,
+			    gfp_t gfp)
 {
 	return security_context_to_sid_core(scontext, scontext_len,
-					    sid, SECSID_NULL, GFP_KERNEL, 0);
+					    sid, SECSID_NULL, gfp, 0);
 }
 
 /**
diff --git a/security/selinux/xfrm.c b/security/selinux/xfrm.c
index 0462cb3ff0a7..98b042630a9e 100644
--- a/security/selinux/xfrm.c
+++ b/security/selinux/xfrm.c
@@ -78,7 +78,8 @@ static inline int selinux_authorizable_xfrm(struct xfrm_state *x)
  * xfrm_user_sec_ctx context.
  */
 static int selinux_xfrm_alloc_user(struct xfrm_sec_ctx **ctxp,
-				   struct xfrm_user_sec_ctx *uctx)
+				   struct xfrm_user_sec_ctx *uctx,
+				   gfp_t gfp)
 {
 	int rc;
 	const struct task_security_struct *tsec = current_security();
@@ -94,7 +95,7 @@ static int selinux_xfrm_alloc_user(struct xfrm_sec_ctx **ctxp,
 	if (str_len >= PAGE_SIZE)
 		return -ENOMEM;
 
-	ctx = kmalloc(sizeof(*ctx) + str_len + 1, GFP_KERNEL);
+	ctx = kmalloc(sizeof(*ctx) + str_len + 1, gfp);
 	if (!ctx)
 		return -ENOMEM;
 
@@ -103,7 +104,7 @@ static int selinux_xfrm_alloc_user(struct xfrm_sec_ctx **ctxp,
 	ctx->ctx_len = str_len;
 	memcpy(ctx->ctx_str, &uctx[1], str_len);
 	ctx->ctx_str[str_len] = '\0';
-	rc = security_context_to_sid(ctx->ctx_str, str_len, &ctx->ctx_sid);
+	rc = security_context_to_sid(ctx->ctx_str, str_len, &ctx->ctx_sid, gfp);
 	if (rc)
 		goto err;
 
@@ -282,9 +283,10 @@ int selinux_xfrm_skb_sid(struct sk_buff *skb, u32 *sid)
  * LSM hook implementation that allocs and transfers uctx spec to xfrm_policy.
  */
 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)
 {
-	return selinux_xfrm_alloc_user(ctxp, uctx);
+	return selinux_xfrm_alloc_user(ctxp, uctx, gfp);
 }
 
 /*
@@ -332,7 +334,7 @@ int selinux_xfrm_policy_delete(struct xfrm_sec_ctx *ctx)
 int selinux_xfrm_state_alloc(struct xfrm_state *x,
 			     struct xfrm_user_sec_ctx *uctx)
 {
-	return selinux_xfrm_alloc_user(&x->security, uctx);
+	return selinux_xfrm_alloc_user(&x->security, uctx, GFP_KERNEL);
 }
 
 /*