Issue #20950 has been reported by peterzhu2118 (Peter Zhu). ---------------------------------------- Bug #20950: Use-after-free in ep in Proc#dup for ifunc procs https://bugs.ruby-lang.org/issues/20950 * Author: peterzhu2118 (Peter Zhu) * Status: Open * Backport: 3.1: WONTFIX, 3.2: REQUIRED, 3.3: REQUIRED ---------------------------------------- GitHub PR: https://github.com/ruby/ruby/pull/12319 ifunc proc has the ep allocated in the data of the TypedData object. If an ifunc proc is duplicated, the ep points to the ep of the source object. If the source object is freed, then the ep of the duplicated object now points to a freed memory region. If we try to use the ep we could crash. For example, the following script crashes: ```ruby p = { a: 1 }.to_proc 100.times do p = p.dup GC.start p.call rescue ArgumentError end ``` This commit changes ifunc proc to also duplicate the ep when it is duplicated. -- https://bugs.ruby-lang.org/