netfilter: nf_ct_ftp: fix out of bounds read in update_nl_seq()

As noticed by Dan Carpenter <error27@gmail.com>, 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.

Cc: stable@kernel.org
Signed-off-by: Patrick McHardy <kaber@trash.net>
This commit is contained in:
Patrick McHardy 2010-01-07 18:33:18 +01:00
parent 04bcef2a83
commit aaff23a95a

View file

@ -323,24 +323,24 @@ static void update_nl_seq(struct nf_conn *ct, u32 nl_seq,
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;
}
}