Apple recently faced a security issue and provided a patch to fix it:
About the security
content of iOS 7.0.6
A web site is also available to check if your current OS must be updated:
https://gotofail.com/
An interesting analysis of this - what appears to be - bug can be found in
this article but please note that
I am not sharing the point of view expressed in the conclusion.
I mean, whatever the way, bugs happen.
To make a long story short, it looks like a bad copy & paste duplicated a
"goto fail;" instruction which, in the end, has no condition and is always
evaluated.
As I recently talked about the advantages of using a lint-tool, I wanted to
check if JShint would be
capable of detecting this issue.
However - and fortunately - goto does not exist in JavaScript.
There are several ways to reproduce the same effect than a 'goto' instruction:
- First example, the one-time do / while with break
function main(parameter) {
var
success = false;
do {
if (parameter === "condition1")
break;
if (parameter === "condition2")
break;
break;
success = true;
} while(0);
if (success) {
alert("Do");
} else {
alert("Don't");
}
}
main("condition3");
JSHint produces a warning:
10 Unreachable 'success' after 'break'.
- Second example, return in a separate function
function testCondition(parameter) {
if (parameter === "condition1")
return false;
if (parameter === "condition2")
return false;
return false;
return true;
}
function main(parameter) {
if (testCondition(parameter)) {
alert("Do");
} else {
alert("Don't");
}
}
main("condition3");
JSHint produces a warning:
7 Unreachable 'return' after 'return'.
- Last example, exceptions
function main(parameter) {
try {
if (parameter === "condition1")
throw "fail";
if (parameter === "condition2")
throw "fail";
throw "fail";
alert("Do");
} catch (e) {
alert("Don't");
}
}
main("condition3");
JSHint produces a warning:
8 Unreachable 'alert' after 'throw'.
To conclude, JShint is
capable of detecting an unreachable code and generates the appropriate warning.
It also means that all the warnings are meaningful and should be carefully
considered.
