Re: problem with conntrack utility and kernel 2.6.14

[Pablo Neira <pablo@eurodev.net>]

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Hi,

Deti Fliegl wrote:
> Pablo Neira wrote:
> 
>> This problem was already fixed days ago in libnetfilter_conntrack on 
>> Oct 17, see SVN. I'm not able to reproduce what you're reporting. Please 
> 
> What I'm doing is to request a file from a local webserver in an endless 
> loop.
> 
>> send me a gdb backtrace, together with other extra info. Are you 
>> running conntrack on a x86?
> 
> It's a x64_64 system.
> 
> Backtrace from gdb:

Thanks for the very detailed report. The patch fixes some aligment 
issues that I didn't handle properly :(. Please, give a try to the patch 
attached and tell if it fixes your problem.

-- 
Pablo

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Index: src/libnetfilter_conntrack.c
===================================================================
--- src/libnetfilter_conntrack.c	(revision 4394)
+++ src/libnetfilter_conntrack.c	(working copy)
@@ -424,9 +424,8 @@
 					  struct nlmsghdr *nlh, void *arg)
 {
 	struct nfgenmsg *nfmsg;
-	int min_len = sizeof(struct nfgenmsg) + sizeof(struct nlmsghdr);
 	struct nfattr *attr = NFM_NFA(NLMSG_DATA(nlh));
-	int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len);
+	int attrlen = NLMSG_LENGTH(nlh->nlmsg_len) - NFNL_HEADER_LEN;
 	struct nfct_conntrack ct;
 	unsigned int flags = 0;
 	int type = NFNL_MSG_TYPE(nlh->nlmsg_type), ret = 0;
@@ -435,7 +434,7 @@
 
 	nfmsg = NLMSG_DATA(nlh);
 
-	if (nlh->nlmsg_len < min_len)
+	if (NLMSG_LENGTH(nlh->nlmsg_len) < NFNL_HEADER_LEN)
 		return -EINVAL;
 
 	while (NFA_OK(attr, attrlen)) {
@@ -666,9 +665,8 @@
 				       struct nlmsghdr *nlh, void *arg)
 {
 	struct nfgenmsg *nfmsg;
-	int min_len = sizeof(struct nfgenmsg) + sizeof(struct nlmsghdr);
 	struct nfattr *attr = NFM_NFA(NLMSG_DATA(nlh));
-	int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len);
+	int attrlen = NLMSG_LENGTH(nlh->nlmsg_len) - NFNL_HEADER_LEN;
 	struct nfct_expect exp;
 	int type = NFNL_MSG_TYPE(nlh->nlmsg_type), ret = 0;
 
@@ -676,7 +674,7 @@
 
 	nfmsg = NLMSG_DATA(nlh);
 
-	if (nlh->nlmsg_len < min_len)
+	if (NLMSG_LENGTH(nlh->nlmsg_len) < NFNL_HEADER_LEN)
 		return -EINVAL;
 
 	while (NFA_OK(attr, attrlen)) {