From: mtasaka@...
Date: 2014-07-10T09:24:08+00:00
Subject: [ruby-core:63624] [ruby-trunk - Bug #10019] segmentation fault/buffer overrun in pack.c (encodes)

Issue #10019 has been updated by Mamoru Tasaka.


Looking at encodes(), it seems at least when
* len = 3070 (= ((4096 - 4) / 4 * 3 + 1))
* tail_lf = 1
encodes() causes segv at https://github.com/ruby/ruby/blob/trunk/pack.c#L987

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Bug #10019: segmentation fault/buffer overrun in pack.c (encodes)
https://bugs.ruby-lang.org/issues/10019#change-47677

* Author: Will Wood
* Status: Feedback
* Priority: Low
* Assignee: 
* Category: core
* Target version: 
* ruby -v: ruby 2.1.2p168 (2014-07-06 revision 46721) [i386-mingw32]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
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While working with an AWS sample I hit a segmentation fault.  The same sample works under 1.9.3.  It appeared to be coming from pack.c function encodes.  After looking at the source there's a 4K buffer allocated on the stack.  I made a minor change to base the buffer length off of the incoming buffer length with a pad and allocate it off the heap.  Anyway, after fixing this my code sample runs fine.  I'm including a patch file and the sample code.

---Files--------------------------------
pack.patch (2.74 KB)
BucketTest.rb (326 Bytes)


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