RB: don't flag code-injection for dynamic loading where an attacker only controls a substring #10883
There are no files selected for viewing
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
|
|
@@ -11,20 +11,41 @@ private import codeql.ruby.dataflow.BarrierGuards | |
| * adding your own. | ||
| */ | ||
| module CodeInjection { | ||
| /** Flow states used to distinguish whether an attacker controls the entire string. */ | ||
| module FlowState { | ||
| /** Flow state used for normal tainted data, where an attacker might only control a substring. */ | ||
| DataFlow::FlowState substring() { result = "substring" } | ||
|
|
||
| /** Flow state used for data that is entirely controlled by the attacker. */ | ||
| DataFlow::FlowState full() { result = "full" } | ||
| } | ||
|
|
||
| /** | ||
| * A data flow source for "Code injection" vulnerabilities. | ||
| */ | ||
| abstract class Source extends DataFlow::Node { | ||
| /** Gets a flow state for which this is a source. */ | ||
| DataFlow::FlowState getAFlowState() { result = [FlowState::substring(), FlowState::full()] } | ||
| } | ||
|
|
||
| /** | ||
| * A data flow sink for "Code injection" vulnerabilities. | ||
| */ | ||
| abstract class Sink extends DataFlow::Node { | ||
| /** Holds if this sink is safe for an attacker that only controls a substring. */ | ||
| DataFlow::FlowState getAFlowState() { result = [FlowState::substring(), FlowState::full()] } | ||
| } | ||
|
|
||
| /** | ||
| * A sanitizer for "Code injection" vulnerabilities. | ||
| */ | ||
| abstract class Sanitizer extends DataFlow::Node { | ||
| /** | ||
| * Gets a flow state for which this is a sanitizer. | ||
| * Sanitizes all states if the result is empty. | ||
| */ | ||
| DataFlow::FlowState getAFlowState() { none() } | ||
| } | ||
|
|
||
| /** | ||
| * DEPRECATED: Use `Sanitizer` instead. | ||
|
|
@@ -42,6 +63,35 @@ module CodeInjection { | |
| * A call that evaluates its arguments as Ruby code, considered as a flow sink. | ||
| */ | ||
| class CodeExecutionAsSink extends Sink { | ||
| CodeExecution c; | ||
|
|
||
| CodeExecutionAsSink() { this = c.getCode() } | ||
|
|
||
| /** Gets a flow state for which this is a sink. */ | ||
| override DataFlow::FlowState getAFlowState() { | ||
| if c.runsArbitraryCode() | ||
| then result = [FlowState::substring(), FlowState::full()] // If it runs immediately, then it's always vulnerable. | ||
| else result = FlowState::full() // If it "just" loads something, then it's only vulnerable if the attacker controls the entire string. | ||
| } | ||
| } | ||
|
|
||
| private import codeql.ruby.AST as Ast | ||
|
|
||
| /** | ||
| * A string-concatenation that sanitizes the `full()` state. | ||
| */ | ||
| class StringConcatenationSanitizer extends Sanitizer { | ||
| StringConcatenationSanitizer() { | ||
| // string concatenations sanitize the `full` state, as an attacker no longer controls the entire string | ||
|
There was a problem hiding this comment. This seems overly restrictive. User input flowing into params[:foo] = "f; end; system('bad stuff'); def g"
eval("def " + params[:foo] + "; end")
# => def f; end; system('bad stuff'); def g; endThere was a problem hiding this comment. It only restricts flow for the But I found an unrelated issue while adding a test that confirmed that it works: #10968 There was a problem hiding this comment. Interesting. I tested this myself to check that it didn't work correctly, and I guess was also affected by that issue. |
||
| exists(Ast::AstNode str | | ||
| str instanceof Ast::StringLiteral | ||
| or | ||
| str instanceof Ast::AddExpr | ||
| | | ||
| this.asExpr().getExpr() = str | ||
| ) | ||
| } | ||
|
|
||
| override DataFlow::FlowState getAFlowState() { result = FlowState::full() } | ||
| } | ||
| } | ||
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.