You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
FUZZing with XHR (2/2)<br />
Similar considerations also apply to<br />
web sockets network calls<br />
• A race condition may happen If your callback code relies on some object/function that has been GC’ed or is uninitialized at<br />
the moment of callback execution<br />
• E.g. Suppose your callback code executes some mutation operations on an object bound to xhr and you’re running multiple<br />
concurrent xhr calls<br />
Create<br />
xhr#1<br />
object<br />
Open<br />
xhr#1<br />
Send<br />
xhr#1<br />
Execute<br />
callback<br />
2<br />
GC<br />
Create<br />
xhr#2<br />
object<br />
Open<br />
xhr#2<br />
Send<br />
xhr#2<br />
Execute<br />
callback<br />
1<br />
3<br />
XHR<br />
methods/<br />
attribute<br />
tweaking<br />
• Some other race conditions may happen when xhr are recursive:<br />
Create<br />
xhr<br />
object<br />
Open xhr<br />
Send xhr<br />
Execute<br />
callback
Change language