ICMP timestamp messages and IP source route options require
timestamps to be in milliseconds modulo 24 hours from
midnight UT format.

Timestamps are calculated from realtime by making a call
to getnstimeofday() which uses struct timespec.
timespec is not y2038 safe.
Replace the above calls with y2038 safe current_nw_time() to
obtain network timestamps which uses y2038 safe struct timespec64.

Signed-off-by: Deepa Dinamani <deepa.ker...@gmail.com>
Cc: "David S. Miller" <da...@davemloft.net>
Cc: Alexey Kuznetsov <kuz...@ms2.inr.ac.ru>
Cc: James Morris <jmor...@namei.org>
Cc: Hideaki YOSHIFUJI <yoshf...@linux-ipv6.org>
Cc: Patrick McHardy <ka...@trash.net>
---
 net/ipv4/icmp.c       |  5 +----
 net/ipv4/ip_options.c | 13 +++++--------
 2 files changed, 6 insertions(+), 12 deletions(-)

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 36e2697..e43dfa3 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -931,7 +931,6 @@ static bool icmp_echo(struct sk_buff *skb)
  */
 static bool icmp_timestamp(struct sk_buff *skb)
 {
-       struct timespec tv;
        struct icmp_bxm icmp_param;
        /*
         *      Too short.
@@ -942,9 +941,7 @@ static bool icmp_timestamp(struct sk_buff *skb)
        /*
         *      Fill in the current time as ms since midnight UT:
         */
-       getnstimeofday(&tv);
-       icmp_param.data.times[1] = htonl((tv.tv_sec % 86400) * MSEC_PER_SEC +
-                                        tv.tv_nsec / NSEC_PER_MSEC);
+       icmp_param.data.times[1] = current_nw_timestamp();
        icmp_param.data.times[2] = icmp_param.data.times[1];
        if (skb_copy_bits(skb, 0, &icmp_param.data.times[0], 4))
                BUG();
diff --git a/net/ipv4/ip_options.c b/net/ipv4/ip_options.c
index bd24679..6958e7c 100644
--- a/net/ipv4/ip_options.c
+++ b/net/ipv4/ip_options.c
@@ -58,10 +58,8 @@ void ip_options_build(struct sk_buff *skb, struct ip_options 
*opt,
                if (opt->ts_needaddr)
                        ip_rt_get_source(iph+opt->ts+iph[opt->ts+2]-9, skb, rt);
                if (opt->ts_needtime) {
-                       struct timespec tv;
                        __be32 midtime;
-                       getnstimeofday(&tv);
-                       midtime = htonl((tv.tv_sec % 86400) * MSEC_PER_SEC + 
tv.tv_nsec / NSEC_PER_MSEC);
+                       midtime = current_nw_timestamp();
                        memcpy(iph+opt->ts+iph[opt->ts+2]-5, &midtime, 4);
                }
                return;
@@ -415,11 +413,10 @@ int ip_options_compile(struct net *net,
                                        break;
                                }
                                if (timeptr) {
-                                       struct timespec tv;
-                                       u32  midtime;
-                                       getnstimeofday(&tv);
-                                       midtime = (tv.tv_sec % 86400) * 
MSEC_PER_SEC + tv.tv_nsec / NSEC_PER_MSEC;
-                                       put_unaligned_be32(midtime, timeptr);
+                                       __be32  midtime;
+
+                                       midtime = current_nw_timestamp();
+                                       memcpy(timeptr, &midtime, 4);
                                        opt->is_changed = 1;
                                }
                        } else if ((optptr[3]&0xF) != IPOPT_TS_PRESPEC) {
-- 
1.9.1

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