[5/9] netfilter: nf_ct_ftp: fix out of bounds read in update_nl_seq()

From: Greg KH
Date: Thu Jan 14 2010 - 17:52:44 EST


2.6.31-stable review patch. If anyone has any objections, please let us know.

------------------

From: Patrick McHardy <kaber@xxxxxxxxx>

commit aaff23a95aea5f000895f50d90e91f1e2f727002 upstream.

As noticed by Dan Carpenter <error27@xxxxxxxxx>, update_nl_seq()
currently contains an out of bounds read of the seq_aft_nl array
when looking for the oldest sequence number position.

Fix it to only compare valid positions.

Signed-off-by: Patrick McHardy <kaber@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
net/netfilter/nf_conntrack_ftp.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)

--- a/net/netfilter/nf_conntrack_ftp.c
+++ b/net/netfilter/nf_conntrack_ftp.c
@@ -323,24 +323,24 @@ static void update_nl_seq(struct nf_conn
struct nf_ct_ftp_master *info, int dir,
struct sk_buff *skb)
{
- unsigned int i, oldest = NUM_SEQ_TO_REMEMBER;
+ unsigned int i, oldest;

/* Look for oldest: if we find exact match, we're done. */
for (i = 0; i < info->seq_aft_nl_num[dir]; i++) {
if (info->seq_aft_nl[dir][i] == nl_seq)
return;
-
- if (oldest == info->seq_aft_nl_num[dir] ||
- before(info->seq_aft_nl[dir][i],
- info->seq_aft_nl[dir][oldest]))
- oldest = i;
}

if (info->seq_aft_nl_num[dir] < NUM_SEQ_TO_REMEMBER) {
info->seq_aft_nl[dir][info->seq_aft_nl_num[dir]++] = nl_seq;
- } else if (oldest != NUM_SEQ_TO_REMEMBER &&
- after(nl_seq, info->seq_aft_nl[dir][oldest])) {
- info->seq_aft_nl[dir][oldest] = nl_seq;
+ } else {
+ if (before(info->seq_aft_nl[dir][0], info->seq_aft_nl[dir][1]))
+ oldest = 0;
+ else
+ oldest = 1;
+
+ if (after(nl_seq, info->seq_aft_nl[dir][oldest]))
+ info->seq_aft_nl[dir][oldest] = nl_seq;
}
}



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