Re: Panic: file charset-iconv.c: line 83 (charset_to_utf8_try): assertion failed: (srcleft <= CHARSET_MAX_PENDING_BUF_SIZE)

This is just the test case, not a patch as yet. I don’t have a 2.4 installation at this time.

Alex

— cut here and base64 decode this tarball --
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> On May 9, 2026, at 11:28 AM, John Stoffel <[email protected]> wrote:
> 
>>>>>> "Alex" == Alex Rosenberg via dovecot <[email protected] <mailto:[email protected]>> writes:
> 
>> Looks like attachments are stripped by this Mailman instance. I’ll
>> send it to anybody that wants it; I made it an attachment to try to
>> avoid crashing the server of everybody on this list.  Alex
> 
> Just send the patch inline, or maybe put it up somewhere where people
> can find it more easily?  If you're including a test case (great!
> please do!) then I can understand the problem.  But maybe there's a
> way to encode the test case so it will work inline, but then get
> tested properly.
> 
> And does this same issue hit under 2.4?  
> 
> Thanks,
> John
> 
> 
>>> On May 8, 2026, at 3:27 PM, Alex Rosenberg via dovecot <[email protected]> wrote:
>>> 
>>> Attached is an LLM-reduced reproduction of the crash in the title. My particular setup is dovecot 2.3.21.1 (d492236fa0) in a FreeBSD jail (13.5). I realize that this is an older release but there is no FreeBSD port/pkg for dovecot 2.4.x yet.
>>> 
>>> The message in the attachment is reduced from an old (2017!) email to one of the LLVM compiler mailing lists. The original malformed email had this header:
>>> X-Mailer: Evolution 3.22.5 (3.22.5-1.fc25)
>>> 
>>> The bug occurs when dovecot's FTS indexer processes a MIME part that:
>>> 1. Declares charset="UTF-7"
>>> 2. Contains base64-encoded content that, when decoded, has bare '+' characters
>>> 3. Causes UTF-7 decoder buffer overflow in charset-iconv.c:83
>>> 
>>> The base64 content decodes to C source code with expressions like:                                                                       
>>> - argc + 4
>>> - state++
>>> - state--
>>> 
>>> These '+' characters in UTF-7 context cause the decoder's pending buffer to exceed CHARSET_MAX_PENDING_BUF_SIZE, triggering the assertion failure.                                                                                                                                
>>> 
>>> Alex
>>> 
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> 
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