Editing Nested function (section)

=== No-execute stacks ===

[[GNU Compiler Collection|GCC]]'s implementation of nested functions causes a loss of [[NX bit|no-execute]] [[Call stack|stacks]] (NX stacks). This implementation calls nested functions through a [[jump instruction]] placed on the machine stack at runtime. This requires the stack to be executable. No-execute stacks and nested functions are therefore mutually exclusive in GCC. If a nested function is used in the development of a program, then the NX stack is silently lost, unless GCC is called with the <code>&#8209;Wtrampoline</code> option to alert of the condition. Software engineered using [[Software Development Security|Secure Development Lifecycle]] often do not allow the use of nested functions in this particular compiler due to the loss of NX stacks.<ref>{{cite web
 | url = http://www.owasp.org/index.php/C-Based_Toolchain_Hardening#GCC.2FBinutils
 | title = C-Based Toolchain Hardening
 | last = Walton
 | first = Jeffrey
 | publisher = The Open Web Application Security Project (OWASP)
 | access-date = 28 February 2017
}}</ref>