From ccdf6ce6a8dba374668ae9b4d763e19903611c38 Mon Sep 17 00:00:00 2001
From: Matti Vaittinen <matti.vaittinen@nokia.com>
Date: Mon, 11 Jan 2016 14:26:19 +0200
Subject: [PATCH] net: netlink: Fix multicast group storage allocation for
families with more than one groups
Multicast groups are stored in global buffer. Check for needed buffer size
incorrectly compares buffer size to first id for family. This means that
for families with more than one mcast id one may allocate too small buffer
and end up writing rest of the groups to some unallocated memory. Fix the
buffer size check to compare allocated space to last mcast id for the
family.
Tested on ARM using kernel 3.14
Signed-off-by: Matti Vaittinen <matti.vaittinen@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/netlink/genetlink.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index bc0e504f33a6..a992083c0a64 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -185,7 +185,7 @@ static int genl_allocate_reserve_groups(int n_groups, int *first_id)
}
}
- if (id >= mc_groups_longs * BITS_PER_LONG) {
+ if (id + n_groups >= mc_groups_longs * BITS_PER_LONG) {
unsigned long new_longs = mc_groups_longs +
BITS_TO_LONGS(n_groups);
size_t nlen = new_longs * sizeof(unsigned long);
--
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