[PATCH 45/59] LSM: Use lsm_context in security_inode_getsecctx

[Casey Schaufler]

From: Casey Schaufler <cschaufler at schaufler-ca.com>

Convert security_inode_getsecctx to use the lsm_context structure
instead of a context/secid pair. There is some scaffolding involved
that will be removed when the related data is updated.

Signed-off-by: Casey Schaufler <casey at schaufler-ca.com>
---
 fs/kernfs/inode.c        | 11 +++++------
 fs/nfsd/nfs4xdr.c        | 14 ++++++--------
 include/linux/security.h |  5 +++--
 security/security.c      | 11 ++---------
 4 files changed, 16 insertions(+), 25 deletions(-)

diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c
index 460e611b1938..41c5afc698fc 100644
--- a/fs/kernfs/inode.c
+++ b/fs/kernfs/inode.c
@@ -351,8 +351,7 @@ static int kernfs_security_xattr_set(const struct xattr_handler *handler,
 {
 	struct kernfs_node *kn = inode->i_private;
 	struct kernfs_iattrs *attrs;
-	void *secdata;
-	u32 secdata_len = 0;
+	struct lsm_context lc = { .context = NULL, .len = 0, };
 	int error;
 
 	attrs = kernfs_iattrs(kn);
@@ -362,16 +361,16 @@ static int kernfs_security_xattr_set(const struct xattr_handler *handler,
 	error = security_inode_setsecurity(inode, suffix, value, size, flags);
 	if (error)
 		return error;
-	error = security_inode_getsecctx(inode, &secdata, &secdata_len);
+	error = security_inode_getsecctx(inode, &lc);
 	if (error)
 		return error;
 
 	mutex_lock(&kernfs_mutex);
-	error = kernfs_node_setsecdata(attrs, &secdata, &secdata_len);
+	error = kernfs_node_setsecdata(attrs, (void **)&lc.context, &lc.len);
 	mutex_unlock(&kernfs_mutex);
 
-	if (secdata)
-		security_release_secctx(secdata, secdata_len);
+	if (lc.context)
+		security_release_secctx(lc.context, lc.len);
 	return error;
 }
 
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 3de42a729093..1bf34730d054 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2420,8 +2420,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 	__be32 status;
 	int err;
 	struct nfs4_acl *acl = NULL;
-	void *context = NULL;
-	int contextlen;
+	struct lsm_context lc = { .context = NULL, .len = 0, };
 	bool contextsupport = false;
 	struct nfsd4_compoundres *resp = rqstp->rq_resp;
 	u32 minorversion = resp->cstate.minorversion;
@@ -2477,8 +2476,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 	if ((bmval2 & FATTR4_WORD2_SECURITY_LABEL) ||
 	     bmval0 & FATTR4_WORD0_SUPPORTED_ATTRS) {
 		if (exp->ex_flags & NFSEXP_SECURITY_LABEL)
-			err = security_inode_getsecctx(d_inode(dentry),
-						&context, &contextlen);
+			err = security_inode_getsecctx(d_inode(dentry), &lc);
 		else
 			err = -EOPNOTSUPP;
 		contextsupport = (err == 0);
@@ -2907,8 +2905,8 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 	}
 
 	if (bmval2 & FATTR4_WORD2_SECURITY_LABEL) {
-		status = nfsd4_encode_security_label(xdr, rqstp, context,
-								contextlen);
+		status = nfsd4_encode_security_label(xdr, rqstp, lc.context,
+								lc.len);
 		if (status)
 			goto out;
 	}
@@ -2919,8 +2917,8 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 
 out:
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
-	if (context)
-		security_release_secctx(context, contextlen);
+	if (lc.context)
+		security_release_secctx(lc.context, lc.len);
 #endif /* CONFIG_NFSD_V4_SECURITY_LABEL */
 	kfree(acl);
 	if (tempfh) {
diff --git a/include/linux/security.h b/include/linux/security.h
index 2abbaf72779e..b9f824952748 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -441,7 +441,7 @@ void security_release_secctx(char *secdata, u32 seclen);
 void security_inode_invalidate_secctx(struct inode *inode);
 int security_inode_notifysecctx(struct inode *inode, struct lsm_context *cp);
 int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen);
-int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen);
+int security_inode_getsecctx(struct inode *inode, struct lsm_context *cp);
 #else /* CONFIG_SECURITY */
 
 static inline int call_lsm_notifier(enum lsm_event event, void *data)
@@ -1243,7 +1243,8 @@ static inline int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32
 {
 	return -EOPNOTSUPP;
 }
-static inline int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
+static inline int security_inode_getsecctx(struct inode *inode,
+					   struct lsm_context *cp);
 {
 	return -EOPNOTSUPP;
 }
diff --git a/security/security.c b/security/security.c
index f5e332bfcdbe..b7e15cbd4021 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2038,16 +2038,9 @@ int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)
 }
 EXPORT_SYMBOL(security_inode_setsecctx);
 
-int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
+int security_inode_getsecctx(struct inode *inode, struct lsm_context *cp)
 {
-	struct lsm_context lc = { .context = NULL, .len = 0, };
-	int rc;
-
-	rc = call_int_hook(inode_getsecctx, -EOPNOTSUPP, inode, &lc);
-
-	*ctx = (void *)lc.context;
-	*ctxlen = lc.len;
-	return rc;
+	return call_int_hook(inode_getsecctx, -EOPNOTSUPP, inode, cp);
 }
 EXPORT_SYMBOL(security_inode_getsecctx);
 
-- 
2.19.1