4.4-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
commit 3d23401283e80ceb03f765842787e0e79ff598b7 upstream.
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 Signed-off-by: Ben Hutchings ben.hutchings@codethink.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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(-)
--- a/net/ieee802154/6lowpan/reassembly.c +++ b/net/ieee802154/6lowpan/reassembly.c @@ -410,7 +410,6 @@ err: }
#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_ .maxlen = sizeof(unsigned long), .mode = 0644, .proc_handler = proc_doulongvec_minmax, - .extra1 = &zero, .extra2 = &init_net.ieee802154_lowpan.frags.high_thresh }, { --- a/net/ipv4/ip_fragment.c +++ b/net/ipv4/ip_fragment.c @@ -58,14 +58,6 @@ static int sysctl_ipfrag_max_dist __read_mostly = 64; 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; @@ -353,13 +345,13 @@ static int ip_frag_queue(struct ipq *qp, * 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; } @@ -370,7 +362,7 @@ found: * 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; @@ -387,8 +379,8 @@ found:
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) { /* Eat head of the next overlapped fragment @@ -396,7 +388,7 @@ found: */ if (!pskb_pull(next, i)) goto err; - 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; @@ -420,7 +412,13 @@ found: } }
- 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; @@ -431,11 +429,6 @@ found: 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; @@ -511,7 +504,7 @@ static int ip_frag_reasm(struct ipq *qp, }
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); @@ -678,7 +671,7 @@ struct sk_buff *ip_check_defrag(struct n EXPORT_SYMBOL(ip_check_defrag);
#ifdef CONFIG_SYSCTL -static long zero; +static int dist_min;
static struct ctl_table ip4_frags_ns_ctl_table[] = { { @@ -695,7 +688,6 @@ static struct ctl_table ip4_frags_ns_ctl .maxlen = sizeof(unsigned long), .mode = 0644, .proc_handler = proc_doulongvec_minmax, - .extra1 = &zero, .extra2 = &init_net.ipv4.frags.high_thresh }, { @@ -724,7 +716,7 @@ static struct ctl_table ip4_frags_ctl_ta .maxlen = sizeof(int), .mode = 0644, .proc_handler = proc_dointvec_minmax, - .extra1 = &zero + .extra1 = &dist_min, }, { } }; --- a/net/ipv6/netfilter/nf_conntrack_reasm.c +++ b/net/ipv6/netfilter/nf_conntrack_reasm.c @@ -64,7 +64,6 @@ 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[] = { { @@ -80,7 +79,6 @@ static struct ctl_table nf_ct_frag6_sysc .maxlen = sizeof(unsigned long), .mode = 0644, .proc_handler = proc_doulongvec_minmax, - .extra1 = &zero, .extra2 = &init_net.nf_frag.frags.high_thresh }, { --- a/net/ipv6/reassembly.c +++ b/net/ipv6/reassembly.c @@ -547,7 +547,6 @@ static const struct inet6_protocol frag_ };
#ifdef CONFIG_SYSCTL -static int zero;
static struct ctl_table ip6_frags_ns_ctl_table[] = { { @@ -563,8 +562,7 @@ static struct ctl_table ip6_frags_ns_ctl .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 }, {