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if_gre: Ensure that gre_h is aligned

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This commit is contained in:
roy 2021-02-12 19:57:49 +00:00
parent 7271b77973
commit c77555a631
2 changed files with 29 additions and 8 deletions
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30
sys/net/if_gre.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: if_gre.c,v 1.177 2020/01/29 04:18:34 thorpej Exp $ */
/* $NetBSD: if_gre.c,v 1.178 2021/02/12 19:57:49 roy Exp $ */
/*
* Copyright (c) 1998, 2008 The NetBSD Foundation, Inc.
@ -45,7 +45,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: if_gre.c,v 1.177 2020/01/29 04:18:34 thorpej Exp $");
__KERNEL_RCSID(0, "$NetBSD: if_gre.c,v 1.178 2021/02/12 19:57:49 roy Exp $");
#ifdef _KERNEL_OPT
#include "opt_atalk.h"
@ -395,10 +395,26 @@ gre_receive(struct socket *so, void *arg, int events, int waitflag)
sc->sc_error_ev.ev_count++;
return;
}
if (m->m_len < sizeof(*gh) && (m = m_pullup(m, sizeof(*gh))) == NULL) {
GRE_DPRINTF(sc, "m_pullup failed\n");
sc->sc_pullup_ev.ev_count++;
return;
/* If the GRE header is not aligned, slurp it up into a new
* mbuf with space for link headers, in the event we forward
* it. Otherwise, if it is aligned, make sure the entire
* base GRE header is in the first mbuf of the chain.
*/
if (GRE_HDR_ALIGNED_P(mtod(m, void *)) == 0) {
if ((m = m_copyup(m, sizeof(struct gre_h),
(max_linkhdr + 3) & ~3)) == NULL) {
/* XXXJRT new stat, please */
GRE_DPRINTF(sc, "m_copyup failed\n");
sc->sc_pullup_ev.ev_count++;
return;
}
} else if (__predict_false(m->m_len < sizeof(struct gre_h))) {
if ((m = m_pullup(m, sizeof(struct gre_h))) == NULL) {
GRE_DPRINTF(sc, "m_pullup failed\n");
sc->sc_pullup_ev.ev_count++;
return;
}
}
gh = mtod(m, const struct gre_h *);
@ -940,7 +956,6 @@ gre_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
#endif
M_PREPEND(m, sizeof(*gh), M_DONTWAIT);
if (m == NULL) {
IF_DROP(&ifp->if_snd);
error = ENOBUFS;
@ -948,6 +963,7 @@ gre_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
}
gh = mtod(m, struct gre_h *);
KASSERT(GRE_HDR_ALIGNED_P(gh));
gh->flags = 0;
gh->ptype = etype;
/* XXX Need to handle IP ToS. Look at how I handle IP TTL. */

7
sys/net/if_gre.h
View File

@ -1,4 +1,4 @@
/* $NetBSD: if_gre.h,v 1.47 2021/02/03 18:13:13 roy Exp $ */
/* $NetBSD: if_gre.h,v 1.48 2021/02/12 19:57:49 roy Exp $ */
/*
* Copyright (c) 1998, 2008 The NetBSD Foundation, Inc.
@ -131,6 +131,11 @@ struct gre_h {
Present if (rt_pres == 1)
*/
};
#ifdef __NO_STRICT_ALIGNMENT
#define GRE_HDR_ALIGNED_P(gh) 1
#else
#define GRE_HDR_ALIGNED_P(gh) ((((vaddr_t) (gh)) & 3) == 0)
#endif
#ifdef __CTASSERT
__CTASSERT(sizeof(struct gre_h) == 4);
#endif