From: Florian Westphal fw@strlen.de
commit 976bf59c69cd2e2c17f0ab20a14c0e700cba0f15 upstream.
This uses a pseudo-linearization scheme with a 64k global buffer, but BIG TCP arrival means IPv6 TCP stack can generate skbs that exceed this size.
In practice, IRC commands are not expected to exceed 512 bytes, plus this is interactive protocol, so we should not see large packets in practice.
Given most IRC connections nowadays use TLS so this helper could also be removed in the near future.
Fixes: 7c4e983c4f3c ("net: allow gso_max_size to exceed 65536") Fixes: 0fe79f28bfaf ("net: allow gro_max_size to exceed 65536") Signed-off-by: Florian Westphal fw@strlen.de Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/netfilter/nf_conntrack_irc.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/net/netfilter/nf_conntrack_irc.c b/net/netfilter/nf_conntrack_irc.c index 08ee4e760a3d..1796c456ac98 100644 --- a/net/netfilter/nf_conntrack_irc.c +++ b/net/netfilter/nf_conntrack_irc.c @@ -39,6 +39,7 @@ unsigned int (*nf_nat_irc_hook)(struct sk_buff *skb, EXPORT_SYMBOL_GPL(nf_nat_irc_hook);
#define HELPER_NAME "irc" +#define MAX_SEARCH_SIZE 4095
MODULE_AUTHOR("Harald Welte laforge@netfilter.org"); MODULE_DESCRIPTION("IRC (DCC) connection tracking helper"); @@ -121,6 +122,7 @@ static int help(struct sk_buff *skb, unsigned int protoff, int i, ret = NF_ACCEPT; char *addr_beg_p, *addr_end_p; typeof(nf_nat_irc_hook) nf_nat_irc; + unsigned int datalen;
/* If packet is coming from IRC server */ if (dir == IP_CT_DIR_REPLY) @@ -140,8 +142,12 @@ static int help(struct sk_buff *skb, unsigned int protoff, if (dataoff >= skb->len) return NF_ACCEPT;
+ datalen = skb->len - dataoff; + if (datalen > MAX_SEARCH_SIZE) + datalen = MAX_SEARCH_SIZE; + spin_lock_bh(&irc_buffer_lock); - ib_ptr = skb_header_pointer(skb, dataoff, skb->len - dataoff, + ib_ptr = skb_header_pointer(skb, dataoff, datalen, irc_buffer); if (!ib_ptr) { spin_unlock_bh(&irc_buffer_lock); @@ -149,7 +155,7 @@ static int help(struct sk_buff *skb, unsigned int protoff, }
data = ib_ptr; - data_limit = ib_ptr + skb->len - dataoff; + data_limit = ib_ptr + datalen;
/* strlen("\1DCC SENT t AAAAAAAA P\1\n")=24 * 5+MINMATCHLEN+strlen("t AAAAAAAA P\1\n")=14 */ @@ -251,7 +257,7 @@ static int __init nf_conntrack_irc_init(void) irc_exp_policy.max_expected = max_dcc_channels; irc_exp_policy.timeout = dcc_timeout;
- irc_buffer = kmalloc(65536, GFP_KERNEL); + irc_buffer = kmalloc(MAX_SEARCH_SIZE + 1, GFP_KERNEL); if (!irc_buffer) return -ENOMEM;