[Pidgin] #8672: resolver can sigabort trying to allocate a large amount of memory

[Pidgin]

#8672: resolver can sigabort trying to allocate a large amount of memory
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     Reporter:  paul.m  |        Type:  defect   
       Status:  new     |   Component:  libpurple
      Version:  2.5.5   |    Keywords:  resolver 
Launchpad_bug:          |  
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 A failed write call in write_to_parent (dnsquery.c:176) can cause the
 host_resolved function to read wrong data (dnsquery.c:576) and use that
 data as argument to g_malloc, causing a sigabort.

 More exactly, it seems that if the write fails (or 0 bytes are written) it
 is not retried nor the error is set accordingly in write_to_parent, called
 by purple_dnsquery_resolver_run (dnsquery.c:576)
 write_to_parent(child_out, &ai_addrlen, sizeof(ai_addrlen));

 The read of err at dnsquery.c:561 succeeds (err equals 0) as it only
 indicates the return value of getaddrinfo (dnsquery.c:259)

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Ticket URL: <http://developer.pidgin.im/ticket/8672>
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