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authorShan Wei <davidshan@tencent.com>2012-12-04 18:49:15 +0000
committerDavid S. Miller <davem@davemloft.net>2012-12-05 16:01:28 -0500
commitce46cc64d47a8afaf13c300b09a7f9c29f4979b6 (patch)
tree2fcaf39d15b41ee1f92f14eb8035f82eb80a5364 /net/core
parent1642182ea0eedecc5d6f330c43cef8639327f0e5 (diff)
net: neighbour: prohibit negative value for unres_qlen_bytes parameter
unres_qlen_bytes and unres_qlen are int type. But multiple relation(unres_qlen_bytes = unres_qlen * SKB_TRUESIZE(ETH_FRAME_LEN)) will cause type overflow when seting unres_qlen. e.g. $ echo 1027506 > /proc/sys/net/ipv4/neigh/eth1/unres_qlen $ cat /proc/sys/net/ipv4/neigh/eth1/unres_qlen 1182657265 $ cat /proc/sys/net/ipv4/neigh/eth1/unres_qlen_bytes -2147479756 The gutted value is not that we setting。 But user/administrator don't know this is caused by int type overflow. what's more, it is meaningless and even dangerous that unres_qlen_bytes is set with negative number. Because, for unresolved neighbour address, kernel will cache packets without limit in __neigh_event_send()(e.g. (u32)-1 = 2GB). Signed-off-by: Shan Wei <davidshan@tencent.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/neighbour.c17
1 files changed, 12 insertions, 5 deletions
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index f1c0c2e9cad..36fc692e2bd 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -62,6 +62,9 @@ static void __neigh_notify(struct neighbour *n, int type, int flags);
static void neigh_update_notify(struct neighbour *neigh);
static int pneigh_ifdown(struct neigh_table *tbl, struct net_device *dev);
+static int zero;
+static int unres_qlen_max = INT_MAX / SKB_TRUESIZE(ETH_FRAME_LEN);
+
static struct neigh_table *neigh_tables;
#ifdef CONFIG_PROC_FS
static const struct file_operations neigh_stat_seq_fops;
@@ -1787,8 +1790,7 @@ static int neightbl_fill_parms(struct sk_buff *skb, struct neigh_parms *parms)
nla_put_u32(skb, NDTPA_QUEUE_LENBYTES, parms->queue_len_bytes) ||
/* approximative value for deprecated QUEUE_LEN (in packets) */
nla_put_u32(skb, NDTPA_QUEUE_LEN,
- DIV_ROUND_UP(parms->queue_len_bytes,
- SKB_TRUESIZE(ETH_FRAME_LEN))) ||
+ parms->queue_len_bytes / SKB_TRUESIZE(ETH_FRAME_LEN)) ||
nla_put_u32(skb, NDTPA_PROXY_QLEN, parms->proxy_qlen) ||
nla_put_u32(skb, NDTPA_APP_PROBES, parms->app_probes) ||
nla_put_u32(skb, NDTPA_UCAST_PROBES, parms->ucast_probes) ||
@@ -2777,9 +2779,13 @@ static int proc_unres_qlen(ctl_table *ctl, int write, void __user *buffer,
int size, ret;
ctl_table tmp = *ctl;
+ tmp.extra1 = &zero;
+ tmp.extra2 = &unres_qlen_max;
tmp.data = &size;
- size = DIV_ROUND_UP(*(int *)ctl->data, SKB_TRUESIZE(ETH_FRAME_LEN));
- ret = proc_dointvec(&tmp, write, buffer, lenp, ppos);
+
+ size = *(int *)ctl->data / SKB_TRUESIZE(ETH_FRAME_LEN);
+ ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
+
if (write && !ret)
*(int *)ctl->data = size * SKB_TRUESIZE(ETH_FRAME_LEN);
return ret;
@@ -2865,7 +2871,8 @@ static struct neigh_sysctl_table {
.procname = "unres_qlen_bytes",
.maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .extra1 = &zero,
+ .proc_handler = proc_dointvec_minmax,
},
[NEIGH_VAR_PROXY_QLEN] = {
.procname = "proxy_qlen",