netfilter: nft_log: restrict the log prefix length to 127

First, log prefix will be truncated to NF_LOG_PREFIXLEN-1, i.e. 127,
at nf_log_packet(), so the extra part is useless.

Second, after adding a log rule with a very very long prefix, we will
fail to dump the nft rules after this _special_ one, but acctually,
they do exist. For example:
  # name_65000=$(printf "%0.sQ" {1..65000})
  # nft add rule filter output log prefix "$name_65000"
  # nft add rule filter output counter
  # nft add rule filter output counter
  # nft list chain filter output
  table ip filter {
      chain output {
          type filter hook output priority 0; policy accept;
      }
  }

So now, restrict the log prefix length to NF_LOG_PREFIXLEN-1.

Fixes: 96518518cc41 ("netfilter: add nftables")
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 0 insertions, 1 deletions

diff --git a/net/netfilter/nf_log.c b/net/netfilter/nf_log.c
index 3dca90dc24ad..ffb9e8ada899 100644
--- a/net/netfilter/nf_log.c
+++ b/net/netfilter/nf_log.c
@@ -13,7 +13,6 @@
 /* Internal logging interface, which relies on the real
    LOG target modules */
 
-#define NF_LOG_PREFIXLEN		128
 #define NFLOGGER_NAME_LEN		64
 
 static struct nf_logger __rcu *loggers[NFPROTO_NUMPROTO][NF_LOG_TYPE_MAX] __read_mostly;