This is a regression from compartments landing. The old SJOW used to set aside the frame chain, but the new wrappers don't. NoWaiverWrapper::enter clamps a principal, but there is a chrome code on the frame chain, thus a result of nsScriptSecurityManager::IsCapabilityEnabled() is true. Firefox 5, 6, 7, and trunk are affected. Firefox 3.6 is not affected.
Does anybody think that we have too many ways of expressing "elevated privileges"? Because I think we have too many ways of expressing that.
Created attachment 548628 [details] [diff] [review] Proposed fix This makes nsScriptSecurityManager::IsCapabilityEnabled respect the principals clamping stuff. Note that this patch is relatively delicate in that we have to respect the clamped frame's principal (and privileges). Also note that there is a slight behavioral change with this patch: before it, if we clamped the same principal onto the stack, this code would have continued searching up the stack frame for principal-enabling stack frames. Now it stops at the clamped frame, resulting in strictly reduced privileges. Given the spots where we clamp principals, I'm not really worried about this change causing regressions.
For what it's worth: jst reviewed this in person yesterday. I'll let him stamp it, but I'm going to land this on inbound before he does.
Verified fixed in Firefox 8 with both testcases: Mozilla/5.0 (Windows NT 5.1; rv:8.0) Gecko/20100101 Firefox/8.0 Verified fixed in Firefox 9: Mozilla/5.0 (Windows NT 5.1; rv:9.0) Gecko/20100101 Firefox/9.0 Verified fixed in Firefox 10: Mozilla/5.0 (Windows NT 5.1; rv:10.0a2) Gecko/20111205 Firefox/10.0a2