From 1cef1b19089528db11f221e938f60b9b048945d7 Mon Sep 17 00:00:00 2001 From: Andreas Schwab Date: Thu, 21 Mar 2013 15:50:27 +0100 Subject: [PATCH] Fix stack overflow in getaddrinfo with many results [BZ #15330] * sysdeps/posix/getaddrinfo.c (getaddrinfo): Allocate results and order arrays from heap if bigger than alloca cutoff. --- ChangeLog | 6 ++++++ NEWS | 5 ++++- sysdeps/posix/getaddrinfo.c | 23 +++++++++++++++++++++-- 3 files changed, 31 insertions(+), 3 deletions(-) diff --git a/sysdeps/posix/getaddrinfo.c b/sysdeps/posix/getaddrinfo.c index d95c2d1..2309281 100644 --- a/sysdeps/posix/getaddrinfo.c +++ b/sysdeps/posix/getaddrinfo.c @@ -2489,11 +2489,27 @@ getaddrinfo (const char *name, const char *service, __typeof (once) old_once = once; __libc_once (once, gaiconf_init); /* Sort results according to RFC 3484. */ - struct sort_result results[nresults]; - size_t order[nresults]; + struct sort_result *results; + size_t *order; struct addrinfo *q; struct addrinfo *last = NULL; char *canonname = NULL; + bool malloc_results; + + malloc_results + = !__libc_use_alloca (nresults * (sizeof (*results) + sizeof (size_t))); + if (malloc_results) + { + results = malloc (nresults * (sizeof (*results) + sizeof (size_t))); + if (results == NULL) + { + __free_in6ai (in6ai); + return EAI_MEMORY; + } + } + else + results = alloca (nresults * (sizeof (*results) + sizeof (size_t))); + order = (size_t *) (results + nresults); /* Now we definitely need the interface information. */ if (! check_pf_called) @@ -2664,6 +2680,9 @@ getaddrinfo (const char *name, const char *service, /* Fill in the canonical name into the new first entry. */ p->ai_canonname = canonname; + + if (malloc_results) + free (results); } __free_in6ai (in6ai); -- 1.8.2.3