inet: frags: fix ip6frag_low_thresh boundary

Giving an integer to proc_doulongvec_minmax() is dangerous on 64bit arches,
since linker might place next to it a non zero value preventing a change
to ip6frag_low_thresh.

ip6frag_low_thresh is not used anymore in the kernel, but we do not
want to prematuraly break user scripts wanting to change it.

Since specifying a minimal value of 0 for proc_doulongvec_minmax()
is moot, let's remove these zero values in all defrag units.

Fixes: 6e00f7dd5e4e ("ipv6: frags: fix /proc/sys/net/ipv6/ip6frag_low_thresh")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 3d23401283e80ceb03f765842787e0e79ff598b7)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ieee802154/6lowpan/reassembly.c b/net/ieee802154/6lowpan/reassembly.c
index 44f148a6bb57bb737c35a07e3f070472e209ea23..1790b65944b3ee188608b1a76d4f9a42fb1479d5 100644 (file)
--- a/net/ieee802154/6lowpan/reassembly.c
+++ b/net/ieee802154/6lowpan/reassembly.c
@@ -411,7 +411,6 @@ err:
 }
 
 #ifdef CONFIG_SYSCTL
-static long zero;
 
 static struct ctl_table lowpan_frags_ns_ctl_table[] = {
        {
@@ -428,7 +427,6 @@ static struct ctl_table lowpan_frags_ns_ctl_table[] = {
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = proc_doulongvec_minmax,
-               .extra1         = &zero,
                .extra2         = &init_net.ieee802154_lowpan.frags.high_thresh
        },
        {

diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index 5331a0d683740a3ebacaa31884b66d9fb206eed8..d14d741fb05e571d6d0b03248da77fd993debdee 100644 (file)
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -672,7 +672,7 @@ struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)
 EXPORT_SYMBOL(ip_check_defrag);
 
 #ifdef CONFIG_SYSCTL
-static long zero;
+static int dist_min;
 
 static struct ctl_table ip4_frags_ns_ctl_table[] = {
        {
@@ -689,7 +689,6 @@ static struct ctl_table ip4_frags_ns_ctl_table[] = {
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = proc_doulongvec_minmax,
-               .extra1         = &zero,
                .extra2         = &init_net.ipv4.frags.high_thresh
        },
        {
@@ -705,7 +704,7 @@ static struct ctl_table ip4_frags_ns_ctl_table[] = {
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
-               .extra1         = &zero
+               .extra1         = &dist_min,
        },
        { }
 };

diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index 6613f81e553ae64023229de78e2215ed99b25a24..a1dc0d6a5949863cdba3ac0003009f41e5114d12 100644 (file)
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -63,7 +63,6 @@ struct nf_ct_frag6_skb_cb
 static struct inet_frags nf_frags;
 
 #ifdef CONFIG_SYSCTL
-static long zero;
 
 static struct ctl_table nf_ct_frag6_sysctl_table[] = {
        {
@@ -79,7 +78,6 @@ static struct ctl_table nf_ct_frag6_sysctl_table[] = {
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = proc_doulongvec_minmax,
-               .extra1         = &zero,
                .extra2         = &init_net.nf_frag.frags.high_thresh
        },
        {

diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
index 2127da130dc2cee677059247d5e079a8afbca13d..e1c5fa5e3873f81193fb129073851adfc89964ee 100644 (file)
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -554,7 +554,6 @@ static const struct inet6_protocol frag_protocol = {
 };
 
 #ifdef CONFIG_SYSCTL
-static int zero;
 
 static struct ctl_table ip6_frags_ns_ctl_table[] = {
        {
@@ -570,8 +569,7 @@ static struct ctl_table ip6_frags_ns_ctl_table[] = {
                .data           = &init_net.ipv6.frags.low_thresh,
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
-               .proc_handler   = proc_dointvec_minmax,
-               .extra1         = &zero,
+               .proc_handler   = proc_doulongvec_minmax,
                .extra2         = &init_net.ipv6.frags.high_thresh
        },
        {