Commit ccdf6ce6 authored by Matti Vaittinen's avatar Matti Vaittinen Committed by David S. Miller

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: default avatarMatti Vaittinen <matti.vaittinen@nokia.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 06928b38
...@@ -185,7 +185,7 @@ static int genl_allocate_reserve_groups(int n_groups, int *first_id) ...@@ -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 + unsigned long new_longs = mc_groups_longs +
BITS_TO_LONGS(n_groups); BITS_TO_LONGS(n_groups);
size_t nlen = new_longs * sizeof(unsigned long); size_t nlen = new_longs * sizeof(unsigned long);
......
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