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Revision a165a066

Added by nagachika (Tomoyuki Chikanaga) over 4 years ago

merge revision(s) ade1283ca276f7d589ffd3539fbc7b9817f682d5: [Backport #16136]

    Fix a use-after-free bug by avoiding rb_str_new_frozen

    `str2 = rb_str_new_frozen(str1)` seems to make str1 a shared string that
    refers to str2, but str2 is not marked as STR_IS_SHARED_M nor
    STR_NOFREE.
    `rb_fstring(str2)` frees str2's ptr because it is not marked, and the
    free'ed pointer is the same as str1's ptr.
    After that, accessing str1 may cause use-after-free memory corruption.

    I guess this is a bug of rb_str_new_frozen, but I'm completely unsure
    what it should be; the string states and flags are not documented.
    So, this is a workaround for [Bug #16136].  I confirmed that rspec of
    activeadmin runs gracefully.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_6@67803 b2dd03c8-39d4-4d8f-98ff-823fe69b080e