From 53bc5770aab40e57d95adc3dff771c975b2174e8 Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Thu, 16 May 2019 18:26:36 +0200 Subject: [PATCH] nss_dns: Check for proper A/AAAA address alignment --- ChangeLog | 5 +++++ resolv/nss_dns/dns-host.c | 11 +++++++++-- 2 files changed, 14 insertions(+), 2 deletions(-) diff --git a/ChangeLog b/ChangeLog index cb020262d97..b98bdc46644 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,8 @@ +2019-05-16 Florian Weimer + + * resolv/nss_dns/dns-host.c (getanswer_r): Be more explicit about + struct in_addr/struct in6_addr alignment. + 2019-05-16 Florian Weimer * nis/nss_nis/nis-hosts.c (EXTRA_ARGS, EXTRA_ARGS_DECL): Remove diff --git a/resolv/nss_dns/dns-host.c b/resolv/nss_dns/dns-host.c index 9c15f25f283..9c40051aff0 100644 --- a/resolv/nss_dns/dns-host.c +++ b/resolv/nss_dns/dns-host.c @@ -947,8 +947,15 @@ getanswer_r (struct resolv_context *ctx, linebuflen -= nn; } - linebuflen -= sizeof (align) - ((u_long) bp % sizeof (align)); - bp += sizeof (align) - ((u_long) bp % sizeof (align)); + /* Provide sufficient alignment for both address + families. */ + enum { align = 4 }; + _Static_assert ((align % __alignof__ (struct in_addr)) == 0, + "struct in_addr alignment"); + _Static_assert ((align % __alignof__ (struct in6_addr)) == 0, + "struct in6_addr alignment"); + linebuflen -= align - ((u_long) bp % align); + bp += align - ((u_long) bp % align); if (__glibc_unlikely (n > linebuflen)) goto too_small; -- 2.47.2