lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Wed, 24 Feb 2010 18:49:28 +0100 (MET)
From:	Patrick McHardy <>
Cc:, Patrick McHardy <>,
Subject: netfilter 01/08: nf_conntrack_reasm: properly handle packets fragmented into a single fragment

commit 9e2dcf72023d1447f09c47d77c99b0c49659e5ce
Author: Patrick McHardy <>
Date:   Fri Feb 19 18:18:37 2010 +0100

    netfilter: nf_conntrack_reasm: properly handle packets fragmented into a single fragment
    When an ICMPV6_PKT_TOOBIG message is received with a MTU below 1280,
    all further packets include a fragment header.
    Unlike regular defragmentation, conntrack also needs to "reassemble"
    those fragments in order to obtain a packet without the fragment
    header for connection tracking. Currently nf_conntrack_reasm checks
    whether a fragment has either IP6_MF set or an offset != 0, which
    makes it ignore those fragments.
    Remove the invalid check and make reassembly handle fragment queues
    containing only a single fragment.
    Reported-and-tested-by: Ulrich Weber <>
    Signed-off-by: Patrick McHardy <>

diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index ad1fcda..f1171b7 100644
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -469,7 +469,7 @@ nf_ct_frag6_reasm(struct nf_ct_frag6_queue *fq, struct net_device *dev)
 	/* all original skbs are linked into the NFCT_FRAG6_CB(head).orig */
 	fp = skb_shinfo(head)->frag_list;
-	if (NFCT_FRAG6_CB(fp)->orig == NULL)
+	if (fp && NFCT_FRAG6_CB(fp)->orig == NULL)
 		/* at above code, head skb is divided into two skbs. */
 		fp = fp->next;
@@ -595,12 +595,6 @@ struct sk_buff *nf_ct_frag6_gather(struct sk_buff *skb, u32 user)
 	hdr = ipv6_hdr(clone);
 	fhdr = (struct frag_hdr *)skb_transport_header(clone);
-	if (!(fhdr->frag_off & htons(0xFFF9))) {
-		pr_debug("Invalid fragment offset\n");
-		/* It is not a fragmented frame */
-		goto ret_orig;
-	}
 	if (atomic_read(&nf_init_frags.mem) > nf_init_frags.high_thresh)
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to
More majordomo info at

Powered by blists - more mailing lists