diff --git a/rules/ssrf.go b/rules/ssrf.go new file mode 100644 index 0000000..2e32e84 --- /dev/null +++ b/rules/ssrf.go @@ -0,0 +1,70 @@ +// (c) Copyright 2016 Hewlett Packard Enterprise Development LP +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package rules + +import ( + "go/ast" + "go/types" + + "github.com/GoASTScanner/gas" +) + +type ssrf struct { + gas.MetaData + gas.CallList +} + +// ID returns the identifier for this rule +func (r *ssrf) ID() string { + return r.MetaData.ID +} + +// TODO(jovon) identify these calls from type `http.Client` +// - https://github.com/go-resty/resty -- looks well maintained and popular +// +// Match inspects AST nodes to determine if certain net/http methods are called with variable input +func (r *ssrf) Match(n ast.Node, c *gas.Context) (*gas.Issue, error) { + if node := r.ContainsCallExpr(n, c); node != nil { + for _, arg := range node.Args { + if ident, ok := arg.(*ast.Ident); ok { + obj := c.Info.ObjectOf(ident) + if _, ok := obj.(*types.Var); ok && !gas.TryResolve(ident, c) { + return gas.NewIssue(c, n, r.What, r.Severity, r.Confidence), nil + } + } + } + } + return nil, nil +} + +// NewSSRFCheck detects cases where HTTP requests are sent +func NewSSRFCheck(id string, conf gas.Config) (gas.Rule, []ast.Node) { + rule := &readfile{ + CallList: gas.NewCallList(), + MetaData: gas.MetaData{ + ID: id, + What: "Potential HTTP request made with variable url", + Severity: gas.Medium, + Confidence: gas.High, + }, + } + rule.Add("net/http", "Do") + rule.Add("net/http", "Get") + rule.Add("net/http", "Head") + rule.Add("net/http", "Post") + rule.Add("net/http", "PostForm") + rule.Add("net/http", "RoundTrip") + return rule, []ast.Node{(*ast.CallExpr)(nil)} +}