diff options
Diffstat (limited to 'net/netfilter/nf_conntrack_irc.c')
| -rw-r--r-- | net/netfilter/nf_conntrack_irc.c | 56 |
1 files changed, 44 insertions, 12 deletions
diff --git a/net/netfilter/nf_conntrack_irc.c b/net/netfilter/nf_conntrack_irc.c index e40988a2f22f..5703846bea3b 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) @@ -140,23 +142,52 @@ 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); - BUG_ON(ib_ptr == NULL); + if (!ib_ptr) { + spin_unlock_bh(&irc_buffer_lock); + return NF_ACCEPT; + } data = ib_ptr; - data_limit = ib_ptr + skb->len - dataoff; + data_limit = ib_ptr + datalen; + + /* Skip any whitespace */ + while (data < data_limit - 10) { + if (*data == ' ' || *data == '\r' || *data == '\n') + data++; + else + break; + } + + /* strlen("PRIVMSG x ")=10 */ + if (data < data_limit - 10) { + if (strncasecmp("PRIVMSG ", data, 8)) + goto out; + data += 8; + } - /* strlen("\1DCC SENT t AAAAAAAA P\1\n")=24 - * 5+MINMATCHLEN+strlen("t AAAAAAAA P\1\n")=14 */ - while (data < data_limit - (19 + MINMATCHLEN)) { - if (memcmp(data, "\1DCC ", 5)) { + /* strlen(" :\1DCC SENT t AAAAAAAA P\1\n")=26 + * 7+MINMATCHLEN+strlen("t AAAAAAAA P\1\n")=26 + */ + while (data < data_limit - (21 + MINMATCHLEN)) { + /* Find first " :", the start of message */ + if (memcmp(data, " :", 2)) { data++; continue; } + data += 2; + + /* then check that place only for the DCC command */ + if (memcmp(data, "\1DCC ", 5)) + goto out; data += 5; - /* we have at least (19+MINMATCHLEN)-5 bytes valid data left */ + /* we have at least (21+MINMATCHLEN)-(2+5) bytes valid data left */ iph = ip_hdr(skb); pr_debug("DCC found in master %pI4:%u %pI4:%u\n", @@ -172,7 +203,7 @@ static int help(struct sk_buff *skb, unsigned int protoff, pr_debug("DCC %s detected\n", dccprotos[i]); /* we have at least - * (19+MINMATCHLEN)-5-dccprotos[i].matchlen bytes valid + * (21+MINMATCHLEN)-7-dccprotos[i].matchlen bytes valid * data left (== 14/13 bytes) */ if (parse_dcc(data, data_limit, &dcc_ip, &dcc_port, &addr_beg_p, &addr_end_p)) { @@ -185,8 +216,9 @@ static int help(struct sk_buff *skb, unsigned int protoff, /* dcc_ip can be the internal OR external (NAT'ed) IP */ tuple = &ct->tuplehash[dir].tuple; - if (tuple->src.u3.ip != dcc_ip && - tuple->dst.u3.ip != dcc_ip) { + if ((tuple->src.u3.ip != dcc_ip && + ct->tuplehash[!dir].tuple.dst.u3.ip != dcc_ip) || + dcc_port == 0) { net_warn_ratelimited("Forged DCC command from %pI4: %pI4:%u\n", &tuple->src.u3.ip, &dcc_ip, dcc_port); @@ -248,7 +280,7 @@ 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; |