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Subject[PATCH 5.5 081/151] netfilter: xt_recent: recent_seq_next should increase position index
Date
From: Vasily Averin <vvs@virtuozzo.com>

commit db25517a550926f609c63054b12ea9ad515e1a10 upstream.

If .next function does not change position index,
following .show function will repeat output related
to current position index.

Without the patch:
# dd if=/proc/net/xt_recent/SSH # original file outpt
src=127.0.0.4 ttl: 0 last_seen: 6275444819 oldest_pkt: 1 6275444819
src=127.0.0.2 ttl: 0 last_seen: 6275438906 oldest_pkt: 1 6275438906
src=127.0.0.3 ttl: 0 last_seen: 6275441953 oldest_pkt: 1 6275441953
0+1 records in
0+1 records out
204 bytes copied, 6.1332e-05 s, 3.3 MB/s

Read after lseek into middle of last line (offset 140 in example below)
generates expected end of last line and then unexpected whole last line
once again

# dd if=/proc/net/xt_recent/SSH bs=140 skip=1
dd: /proc/net/xt_recent/SSH: cannot skip to specified offset
127.0.0.3 ttl: 0 last_seen: 6275441953 oldest_pkt: 1 6275441953
src=127.0.0.3 ttl: 0 last_seen: 6275441953 oldest_pkt: 1 6275441953
0+1 records in
0+1 records out
132 bytes copied, 6.2487e-05 s, 2.1 MB/s

Cc: stable@vger.kernel.org
Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code ...")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206283
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/netfilter/xt_recent.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/netfilter/xt_recent.c
+++ b/net/netfilter/xt_recent.c
@@ -492,12 +492,12 @@ static void *recent_seq_next(struct seq_
const struct recent_entry *e = v;
const struct list_head *head = e->list.next;

+ (*pos)++;
while (head == &t->iphash[st->bucket]) {
if (++st->bucket >= ip_list_hash_size)
return NULL;
head = t->iphash[st->bucket].next;
}
- (*pos)++;
return list_entry(head, struct recent_entry, list);
}


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