1 files changed, 91 insertions, 0 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 0654bfedcbb0..656e921f3506 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -17,6 +17,9 @@
 #include <linux/xattr.h>
 #include <linux/iversion.h>
 #include <linux/posix_acl.h>
+#include <linux/security.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
 
 static void fuse_advise_use_readdirplus(struct inode *dir)
 {
@@ -456,6 +459,62 @@ static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
 	return ERR_PTR(err);
 }
 
+static int get_security_context(struct dentry *entry, umode_t mode,
+				void **security_ctx, u32 *security_ctxlen)
+{
+	struct fuse_secctx *fctx;
+	struct fuse_secctx_header *header;
+	void *ctx = NULL, *ptr;
+	u32 ctxlen, total_len = sizeof(*header);
+	int err, nr_ctx = 0;
+	const char *name;
+	size_t namelen;
+
+	err = security_dentry_init_security(entry, mode, &entry->d_name,
+					    &name, &ctx, &ctxlen);
+	if (err) {
+		if (err != -EOPNOTSUPP)
+			goto out_err;
+		/* No LSM is supporting this security hook. Ignore error */
+		ctxlen = 0;
+		ctx = NULL;
+	}
+
+	if (ctxlen) {
+		nr_ctx = 1;
+		namelen = strlen(name) + 1;
+		err = -EIO;
+		if (WARN_ON(namelen > XATTR_NAME_MAX + 1 || ctxlen > S32_MAX))
+			goto out_err;
+		total_len += FUSE_REC_ALIGN(sizeof(*fctx) + namelen + ctxlen);
+	}
+
+	err = -ENOMEM;
+	header = ptr = kzalloc(total_len, GFP_KERNEL);
+	if (!ptr)
+		goto out_err;
+
+	header->nr_secctx = nr_ctx;
+	header->size = total_len;
+	ptr += sizeof(*header);
+	if (nr_ctx) {
+		fctx = ptr;
+		fctx->size = ctxlen;
+		ptr += sizeof(*fctx);
+
+		strcpy(ptr, name);
+		ptr += namelen;
+
+		memcpy(ptr, ctx, ctxlen);
+	}
+	*security_ctxlen = total_len;
+	*security_ctx = header;
+	err = 0;
+out_err:
+	kfree(ctx);
+	return err;
+}
+
 /*
  * Atomic create+open operation
  *
@@ -476,6 +535,8 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry,
 	struct fuse_entry_out outentry;
 	struct fuse_inode *fi;
 	struct fuse_file *ff;
+	void *security_ctx = NULL;
+	u32 security_ctxlen;
 
 	/* Userspace expects S_IFREG in create mode */
 	BUG_ON((mode & S_IFMT) != S_IFREG);
@@ -517,7 +578,20 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry,
 	args.out_args[0].value = &outentry;
 	args.out_args[1].size = sizeof(outopen);
 	args.out_args[1].value = &outopen;
+
+	if (fm->fc->init_security) {
+		err = get_security_context(entry, mode, &security_ctx,
+					   &security_ctxlen);
+		if (err)
+			goto out_put_forget_req;
+
+		args.in_numargs = 3;
+		args.in_args[2].size = security_ctxlen;
+		args.in_args[2].value = security_ctx;
+	}
+
 	err = fuse_simple_request(fm, &args);
+	kfree(security_ctx);
 	if (err)
 		goto out_free_ff;
 
@@ -620,6 +694,8 @@ static int create_new_entry(struct fuse_mount *fm, struct fuse_args *args,
 	struct dentry *d;
 	int err;
 	struct fuse_forget_link *forget;
+	void *security_ctx = NULL;
+	u32 security_ctxlen;
 
 	if (fuse_is_bad(dir))
 		return -EIO;
@@ -633,7 +709,22 @@ static int create_new_entry(struct fuse_mount *fm, struct fuse_args *args,
 	args->out_numargs = 1;
 	args->out_args[0].size = sizeof(outarg);
 	args->out_args[0].value = &outarg;
+
+	if (fm->fc->init_security && args->opcode != FUSE_LINK) {
+		err = get_security_context(entry, mode, &security_ctx,
+					   &security_ctxlen);
+		if (err)
+			goto out_put_forget_req;
+
+		BUG_ON(args->in_numargs != 2);
+
+		args->in_numargs = 3;
+		args->in_args[2].size = security_ctxlen;
+		args->in_args[2].value = security_ctx;
+	}
+
 	err = fuse_simple_request(fm, args);
+	kfree(security_ctx);
 	if (err)
 		goto out_put_forget_req;