Date: Tue, 17 Feb 2004 18:39:09 -0800 (PST) From: Roselyn Lee <rosel@verniernetworks.com> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/62989: ether_input computes incorrect m_pkthdr.len when mbufs are chained Message-ID: <200402180239.i1I2d986008465@www.freebsd.org> Resent-Message-ID: <200402180240.i1I2eURk028643@freefall.freebsd.org>
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>Number: 62989
>Category: kern
>Synopsis: ether_input computes incorrect m_pkthdr.len when mbufs are chained
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Tue Feb 17 18:40:30 PST 2004
>Closed-Date:
>Last-Modified:
>Originator: Roselyn Lee
>Release: 4.8
>Organization:
Vernier Networks
>Environment:
4.8-RELEASE FreeBSD
>Description:
m_pkthdr.len that is computed by ether_input() incorrectly assumes m_len is the length of the entire packet. For example, the sis0 driver could return a list of mbufs to hold an incoming packet when the system is out of clusters.
>How-To-Repeat:
>Fix:
void
ether_input(struct ifnet *ifp, struct ether_header *eh, struct mbuf *m)
{
struct ether_header save_eh;
if (eh == NULL) {
if (m->m_len < sizeof(struct ether_header)) {
/* XXX error in the caller. */
m_freem(m);
return;
}
m->m_pkthdr.rcvif = ifp;
eh = mtod(m, struct ether_header *);
m->m_data += sizeof(struct ether_header);
m->m_len -= sizeof(struct ether_header);
- m->m_pkthdr.len = m->m_len;
+ /*
+ * Adjust m_pkthdr.len by the same amount -
+ * do not assume m_pkthdr.len == m_len
+ */
+ m->m_pkthdr.len -= sizeof (struct ether_header);
}
>Release-Note:
>Audit-Trail:
>Unformatted:
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