Need

Enforce proper type assignment in the source code

Context

Description

package main

import (
	"github.com/gin-gonic/gin"
	"net/http"
)

	r := gin.Default()...

In the above code, the variable `data` is declared without a specific type. This is done using the `var` keyword followed by the variable name `data` and then assigning the value using the `=` operator. The value is retrieved from the context `c` of the gin framework using the `MustGet` function with the key "data". This is a vulnerability because the data type of `data` is not explicitly defined, and it will be inferred from the value returned by `c.MustGet("data")`. This can lead to unexpected behavior if the value associated with the key "data" in the context `c` is not of the type that the rest of the code expects. For example, if the rest of the code expects `data` to be a string and tries to perform string operations on it, but the value associated with the key "data" in the context `c` is actually an integer, a runtime error will occur. Moreover, this code is inefficient because every time `data` is used, the Go runtime has to determine its data type dynamically. This can slow down the execution of the program, especially if `data` is used frequently.

package main

import (
	"github.com/gin-gonic/gin"
	"net/http"
)

	r := gin.Default()...

The original code had a vulnerability due to improper type assignation. The variable `data` was declared without a specific type, which can be inefficient and potentially unsafe. The fixed code first checks if the `data` exists in the context using `c.Get("data")`. If it doesn't exist, it returns a `400 Bad Request` status with an error message. Next, it tries to assert the type of `data` to `string` (assuming the data is expected to be a string). If the type assertion fails (i.e., the data is not a string), it returns a `400 Bad Request` status with an error message. Finally, if the data exists and is of the correct type, it returns a `200 OK` status with the data. This way, the code is safer and more efficient because it doesn't need to identify and cast the variable's data type every time it's used.

References