nss_files: Fix /etc/aliases null pointer dereference [BZ #24059]

If /etc/aliases ends with a continuation line (a line that starts
with whitespace) which does not have a trailing newline character,
the file parser would crash due to a null pointer dereference.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

2 files changed, 4 insertions, 0 deletions

diff --git a/support/namespace.h b/support/namespace.h
index f93754934f..4770cf9e90 100644
--- a/support/namespace.h
+++ b/support/namespace.h
@@ -74,6 +74,7 @@ struct support_chroot_configuration
   const char *resolv_conf;      /* /etc/resolv.conf.  */
   const char *hosts;            /* /etc/hosts.  */
   const char *host_conf;        /* /etc/host.conf.  */
+  const char *aliases;          /* /etc/aliases.  */
 };
 
 /* The result of the creation of a chroot.  */
@@ -90,6 +91,7 @@ struct support_chroot
   char *path_resolv_conf;       /* /etc/resolv.conf.  */
   char *path_hosts;             /* /etc/hosts.  */
   char *path_host_conf;         /* /etc/host.conf.  */
+  char *path_aliases;           /* /etc/aliases.  */
 };
 
 /* Create a chroot environment.  The returned data should be freed
diff --git a/support/support_chroot.c b/support/support_chroot.c
index b866b89a18..412ec33f53 100644
--- a/support/support_chroot.c
+++ b/support/support_chroot.c
@@ -56,6 +56,7 @@ support_chroot_create (struct support_chroot_configuration conf)
               &chroot->path_resolv_conf);
   write_file (path_etc, "hosts", conf.hosts, &chroot->path_hosts);
   write_file (path_etc, "host.conf", conf.host_conf, &chroot->path_host_conf);
+  write_file (path_etc, "aliases", conf.aliases, &chroot->path_aliases);
 
   free (path_etc);
 
@@ -77,5 +78,6 @@ support_chroot_free (struct support_chroot *chroot)
   free (chroot->path_resolv_conf);
   free (chroot->path_hosts);
   free (chroot->path_host_conf);
+  free (chroot->path_aliases);
   free (chroot);
 }