From 44f9a2fdc48ccb8bb510b6e1210bf15b3e10afdb Mon Sep 17 00:00:00 2001 From: Chuck Ebbert <76306.1226@compuserve.com> Date: Thu, 4 Jan 2007 12:17:44 -0800 Subject: [PATCH] [NETFILTER]: ebtables: don't compute gap before checking struct type We cannot compute the gap until we know we have a 'struct ebt_entry' and not 'struct ebt_entries'. Failure to check can cause crash. Tested-by: Santiago Garcia Mantinan Acked-by: Al Viro Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Signed-off-by: Andrew Morton Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- net/bridge/netfilter/ebtables.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c index bee558a41800..6c84ccb8c9d7 100644 --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -610,7 +610,7 @@ ebt_check_entry(struct ebt_entry *e, struct ebt_table_info *newinfo, struct ebt_entry_target *t; struct ebt_target *target; unsigned int i, j, hook = 0, hookmask = 0; - size_t gap = e->next_offset - e->target_offset; + size_t gap; int ret; /* don't mess with the struct ebt_entries */ @@ -660,6 +660,7 @@ ebt_check_entry(struct ebt_entry *e, struct ebt_table_info *newinfo, if (ret != 0) goto cleanup_watchers; t = (struct ebt_entry_target *)(((char *)e) + e->target_offset); + gap = e->next_offset - e->target_offset; target = find_target_lock(t->u.name, &ret, &ebt_mutex); if (!target) goto cleanup_watchers; -- 2.20.1