From: Eric Dumazet edumazet@google.com
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) --- net/ieee802154/6lowpan/reassembly.c | 2 -- net/ipv4/ip_fragment.c | 40 ++++++++++--------------- net/ipv6/netfilter/nf_conntrack_reasm.c | 2 -- net/ipv6/reassembly.c | 4 +-- 4 files changed, 17 insertions(+), 31 deletions(-)
diff --git a/net/ieee802154/6lowpan/reassembly.c b/net/ieee802154/6lowpan/reassembly.c index 122a625d9a66..6fca75581e13 100644 --- a/net/ieee802154/6lowpan/reassembly.c +++ b/net/ieee802154/6lowpan/reassembly.c @@ -410,7 +410,6 @@ int lowpan_frag_rcv(struct sk_buff *skb, u8 frag_type) }
#ifdef CONFIG_SYSCTL -static long zero;
static struct ctl_table lowpan_frags_ns_ctl_table[] = { { @@ -427,7 +426,6 @@ 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 e235f62dab58..73c0adc61a65 100644 --- a/net/ipv4/ip_fragment.c +++ b/net/ipv4/ip_fragment.c @@ -56,14 +56,6 @@ */ static const char ip_frag_cache_name[] = "ip4-frags";
-struct ipfrag_skb_cb -{ - struct inet_skb_parm h; - int offset; -}; - -#define FRAG_CB(skb) ((struct ipfrag_skb_cb *)((skb)->cb)) - /* Describe an entry in the "incomplete datagrams" queue. */ struct ipq { struct inet_frag_queue q; @@ -351,13 +343,13 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb) * this fragment, right? */ prev = qp->q.fragments_tail; - if (!prev || FRAG_CB(prev)->offset < offset) { + if (!prev || prev->ip_defrag_offset < offset) { next = NULL; goto found; } prev = NULL; for (next = qp->q.fragments; next != NULL; next = next->next) { - if (FRAG_CB(next)->offset >= offset) + if (next->ip_defrag_offset >= offset) break; /* bingo! */ prev = next; } @@ -368,7 +360,7 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb) * any overlaps are eliminated. */ if (prev) { - int i = (FRAG_CB(prev)->offset + prev->len) - offset; + int i = (prev->ip_defrag_offset + prev->len) - offset;
if (i > 0) { offset += i; @@ -385,8 +377,8 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
err = -ENOMEM;
- while (next && FRAG_CB(next)->offset < end) { - int i = end - FRAG_CB(next)->offset; /* overlap is 'i' bytes */ + while (next && next->ip_defrag_offset < end) { + int i = end - next->ip_defrag_offset; /* overlap is 'i' bytes */
if (i < next->len) { int delta = -next->truesize; @@ -399,7 +391,7 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb) delta += next->truesize; if (delta) add_frag_mem_limit(qp->q.net, delta); - FRAG_CB(next)->offset += i; + next->ip_defrag_offset += i; qp->q.meat -= i; if (next->ip_summed != CHECKSUM_UNNECESSARY) next->ip_summed = CHECKSUM_NONE; @@ -423,7 +415,13 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb) } }
- FRAG_CB(skb)->offset = offset; + /* Note : skb->ip_defrag_offset and skb->dev share the same location */ + dev = skb->dev; + if (dev) + qp->iif = dev->ifindex; + /* Makes sure compiler wont do silly aliasing games */ + barrier(); + skb->ip_defrag_offset = offset;
/* Insert this fragment in the chain of fragments. */ skb->next = next; @@ -434,11 +432,6 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb) else qp->q.fragments = skb;
- dev = skb->dev; - if (dev) { - qp->iif = dev->ifindex; - skb->dev = NULL; - } qp->q.stamp = skb->tstamp; qp->q.meat += skb->len; qp->ecn |= ecn; @@ -514,7 +507,7 @@ static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev, }
WARN_ON(!head); - WARN_ON(FRAG_CB(head)->offset != 0); + WARN_ON(head->ip_defrag_offset != 0);
/* Allocate a new buffer for the datagram. */ ihlen = ip_hdrlen(head); @@ -677,7 +670,7 @@ 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[] = { { @@ -694,7 +687,6 @@ 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 }, { @@ -710,7 +702,7 @@ 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 8bc0df9ad2ab..ff49d1f2c8cb 100644 --- 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 1cb45a0d1a0e..dbe726c9a2ae 100644 --- 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[] = { { @@ -564,8 +563,7 @@ 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 }, {