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>

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 994fa70a910f472ebecc336ddd62d1442014eaba..8e9528ebaa8e1af91172466cc161a83301a217ca 100644 (file)
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -667,7 +667,7 @@ 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[] = {
        {
@@ -684,7 +684,6 @@ 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
        },
        {
@@ -700,7 +699,7 @@ 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 3622aac343aea3cd0d8165d8681f42595735cd90..5e0332014c1738999e680c1853829f384e880284 100644 (file)
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -55,7 +55,6 @@ static const char nf_frags_cache_name[] = "nf-frags";
 static struct inet_frags nf_frags;
 
 #ifdef CONFIG_SYSCTL
-static long zero;
 
 static struct ctl_table nf_ct_frag6_sysctl_table[] = {
        {
@@ -71,7 +70,6 @@ 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 70e4a578b2fb6b2941daeebe4f476214953db047..4979610287e262a873b807a06ac980a17cd1101b 100644 (file)
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -548,7 +548,6 @@ static const struct inet6_protocol frag_protocol = {
 };
 
 #ifdef CONFIG_SYSCTL
-static int zero;
 
 static struct ctl_table ip6_frags_ns_ctl_table[] = {
        {
@@ -565,7 +564,6 @@ static struct ctl_table ip6_frags_ns_ctl_table[] = {
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = proc_doulongvec_minmax,
-               .extra1         = &zero,
                .extra2         = &init_net.ipv6.frags.high_thresh
        },
        {