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authorTom Herbert <tom@herbertland.com>2016-11-01 14:55:25 -0700
committerDavid S. Miller <davem@davemloft.net>2016-11-02 15:26:02 -0400
commit1913540a1328d70edf8597f6c2248575d9d2ad62 (patch)
tree66dee3e9b86d122e3eb0fd40a86e885974b4004e /net/ipv6/ila
parent3de864f8c9e488fa57a28f5deb45bb808810ee92 (diff)
downloadlinux-1913540a1328d70edf8597f6c2248575d9d2ad62.tar.bz2
ila: Fix crash caused by rhashtable changes
commit ca26893f05e86 ("rhashtable: Add rhlist interface") added a field to rhashtable_iter so that length became 56 bytes and would exceed the size of args in netlink_callback (which is 48 bytes). The netlink diag dump function already has been allocating a iter structure and storing the pointed to that in the args of netlink_callback. ila_xlat also uses rhahstable_iter but is still putting that directly in the arg block. Now since rhashtable_iter size is increased we are overwriting beyond the structure. The next field happens to be cb_mutex pointer in netlink_sock and hence the crash. Fix is to alloc the rhashtable_iter and save it as pointer in arg. Tested: modprobe ila ./ip ila add loc 3333:0:0:0 loc_match 2222:0:0:1, ./ip ila list # NO crash now Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/ila')
-rw-r--r--net/ipv6/ila/ila_xlat.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/net/ipv6/ila/ila_xlat.c b/net/ipv6/ila/ila_xlat.c
index 628ae6d85b59..af8f52ee7180 100644
--- a/net/ipv6/ila/ila_xlat.c
+++ b/net/ipv6/ila/ila_xlat.c
@@ -474,7 +474,15 @@ static int ila_nl_dump_start(struct netlink_callback *cb)
{
struct net *net = sock_net(cb->skb->sk);
struct ila_net *ilan = net_generic(net, ila_net_id);
- struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args;
+ struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args[0];
+
+ if (!iter) {
+ iter = kmalloc(sizeof(*iter), GFP_KERNEL);
+ if (!iter)
+ return -ENOMEM;
+
+ cb->args[0] = (long)iter;
+ }
return rhashtable_walk_init(&ilan->rhash_table, &iter->rhiter,
GFP_KERNEL);
@@ -482,16 +490,18 @@ static int ila_nl_dump_start(struct netlink_callback *cb)
static int ila_nl_dump_done(struct netlink_callback *cb)
{
- struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args;
+ struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args[0];
rhashtable_walk_exit(&iter->rhiter);
+ kfree(iter);
+
return 0;
}
static int ila_nl_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
- struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args;
+ struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args[0];
struct rhashtable_iter *rhiter = &iter->rhiter;
struct ila_map *ila;
int ret;