dbfs: validate mknod mode. extract inline code into helper dbfs_mode_type().

2 files changed, 65 insertions, 14 deletions

diff --git a/dbfs-backend.c b/dbfs-backend.c
index c5db978..eea99d0 100644
--- a/dbfs-backend.c
+++ b/dbfs-backend.c
@@ -218,6 +218,26 @@ static int dbfs_inode_write(struct dbfs_inode *ino)
 	return db_meta->get(db_meta, NULL, &key, &val, 0) ? -EIO : 0;
 }
 
+static int dbfs_mode_type(guint32 mode, enum dbfs_inode_type *itype)
+{
+	if (S_ISDIR(mode))
+		*itype = IT_DIR;
+	else if (S_ISCHR(mode) || S_ISBLK(mode))
+		*itype = IT_DEV;
+	else if (S_ISFIFO(mode))
+		*itype = IT_FIFO;
+	else if (S_ISLNK(mode))
+		*itype = IT_SYMLINK;
+	else if (S_ISSOCK(mode))
+		*itype = IT_SOCKET;
+	else if (S_ISREG(mode))
+		*itype = IT_REG;
+	else
+		return -EINVAL;
+	
+	return 0;
+}
+
 int dbfs_inode_read(guint64 ino_n, struct dbfs_inode **ino_out)
 {
 	int rc;
@@ -254,20 +274,8 @@ int dbfs_inode_read(guint64 ino_n, struct dbfs_inode **ino_out)
 
 	/* deduce inode type */
 	mode = GUINT32_FROM_LE(ino->raw_inode->mode);
-	if (S_ISDIR(mode))
-		ino->type = IT_DIR;
-	else if (S_ISCHR(mode) || S_ISBLK(mode))
-		ino->type = IT_DEV;
-	else if (S_ISFIFO(mode))
-		ino->type = IT_FIFO;
-	else if (S_ISLNK(mode))
-		ino->type = IT_SYMLINK;
-	else if (S_ISSOCK(mode))
-		ino->type = IT_SOCKET;
-	else {
-		g_assert(S_ISREG(mode));
-		ino->type = IT_REG;
-	}
+	rc = dbfs_mode_type(mode, &ino->type);
+	g_assert(rc == 0);
 
 	*ino_out = ino;
 
diff --git a/dbfs.c b/dbfs.c
index 292dec2..981bf65 100644
--- a/dbfs.c
+++ b/dbfs.c
@@ -95,6 +95,43 @@ static void dbfs_op_readlink(fuse_req_t req, fuse_ino_t ino)
 	free(val.data);
 }
 
+static int dbfs_mode_validate(mode_t mode)
+{
+	unsigned int ifmt = mode & S_IFMT;
+	int rc = 0;
+
+	if (S_ISREG(mode)) {
+		if (ifmt & ~S_IFREG)
+			rc = -EINVAL;
+	}
+	else if (S_ISDIR(mode)) {
+		if (ifmt & ~S_IFDIR)
+			rc = -EINVAL;
+	}
+	else if (S_ISCHR(mode)) {
+		if (ifmt & ~S_IFCHR)
+			rc = -EINVAL;
+	}
+	else if (S_ISBLK(mode)) {
+		if (ifmt & ~S_IFBLK)
+			rc = -EINVAL;
+	}
+	else if (S_ISFIFO(mode)) {
+		if (ifmt & ~S_IFIFO)
+			rc = -EINVAL;
+	}
+	else if (S_ISLNK(mode))
+		rc = -EINVAL;
+	else if (S_ISSOCK(mode)) {
+		if (ifmt & ~S_IFSOCK)
+			rc = -EINVAL;
+	}
+	else
+		rc = -EINVAL;
+
+	return rc;
+}
+
 static void dbfs_op_mknod(fuse_req_t req, fuse_ino_t parent, const char *name,
 			  mode_t mode, dev_t rdev)
 {
@@ -102,6 +139,12 @@ static void dbfs_op_mknod(fuse_req_t req, fuse_ino_t parent, const char *name,
 	struct dbfs_inode *ino;
 	int rc;
 
+	rc = dbfs_mode_validate(mode);
+	if (rc) {
+		fuse_reply_err(req, rc);
+		return;
+	}
+
 	rc = dbfs_mknod(parent, name, mode, rdev, &ino);
 	if (rc) {
 		fuse_reply_err(req, rc);