Bug #7957

closed

rb_str_modify() does not prevent shared string from rb_str_set_len()

Added by normalperson (Eric Wong) about 11 years ago. Updated about 11 years ago.

Status:

Third Party's Issue

Assignee:

nobu (Nobuyoshi Nakada)

Target version:

2.1.0

ruby -v:

ruby 2.0.0p0 (2013-02-24 revision 39474) [x86_64-linux]

Backport:

[ruby-core:52876]

Description

unicorn HTTP chunk parser may raise "can't set length of shared string (RuntimeError)" in rb_str_set_len().
However, it does call rb_str_modify() before calling rb_str_set_len().

To reproduce:
git clone git://bogomips.org/unicorn
cd unicorn
gem install isolate # needed for unicorn dependencies
git reset --hard v4.6.1
make http # build HTTP parser (needs ragel installed: apt-get install ragel)
ruby -I lib str_modify.rb # failure, raises

apply unicorn_http.patch¶

patch -p1 < unicorn_http.patch
make http # rebuild parser
ruby -I lib str_modify.rb # success (no output)

In my proposed patch, I call rb_str_resize() instead of rb_str_set_len() and that seems to
work around the issue. I even call rb_str_modify() an extra time before rb_str_set_len(),
but rb_str_set_len() still raises...

Files

Download all files

str_modify.rb (408 Bytes) str_modify.rb	script to reproduce the issue (requires unicorn)	normalperson (Eric Wong), 02/25/2013 09:54 PM
unicorn_http.patch (931 Bytes) unicorn_http.patch	proposed patch to unicorn	normalperson (Eric Wong), 02/25/2013 09:54 PM