nixpkgs/pkgs/os-specific/linux/systemd/0008-Fix-a-segfault-in-nscd-when-using-nss-myhostname.patch

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From ef9b259ae24e7bf4ebec04b0b0a44964bc661bb5 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Mon, 4 Feb 2013 12:43:08 +0100
Subject: [PATCH 8/8] Fix a segfault in nscd when using nss-myhostname
MIME-Version: 1.0
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Nscd expects that an NSS module's gethostbyname4_r function returns
its first result in the pre-allocated gaih_addrtuple denoted by **pat.
(See nscd/aicache.c in the Glibc sources.) However, nss-myhostname
doesn't fill in **pat but allocates the first result in buffer, then
sets *pat. So nscd crashes (e.g. when running getent ahosts
my-machine).
Hard to tell if this is a bug in nscd, since there doesn't seem to be
a proper API spec for gethostbyname4_r. But in any case, this patch
fixes the crash by copying the first result to **pat.
---
src/nss-myhostname/nss-myhostname.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/src/nss-myhostname/nss-myhostname.c b/src/nss-myhostname/nss-myhostname.c
index 834a806..b0fb832 100644
--- a/src/nss-myhostname/nss-myhostname.c
+++ b/src/nss-myhostname/nss-myhostname.c
@@ -176,7 +176,11 @@ enum nss_status _nss_myhostname_gethostbyname4_r(
/* Verify the size matches */
assert(idx == ms);
- *pat = r_tuple_prev;
+ /* Nscd expects us to store the first record in **pat. */
+ if (*pat)
+ **pat = *r_tuple_prev;
+ else
+ *pat = r_tuple_prev;
if (ttlp)
*ttlp = 0;
--
1.8.1