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authorSabrina Dubroca <sd@queasysnail.net>2017-05-03 16:43:19 +0200
committerSteffen Klassert <steffen.klassert@secunet.com>2017-05-04 07:30:59 +0200
commit9b3eb54106cf6acd03f07cf0ab01c13676a226c2 (patch)
treed141faeb13e5f9d8c44a08157e4a7f59c24ee9dd
parent0e78a87306a6f55b1c7bbafad1de62c3975953ca (diff)
xfrm: fix stack access out of bounds with CONFIG_XFRM_SUB_POLICY
When CONFIG_XFRM_SUB_POLICY=y, xfrm_dst stores a copy of the flowi for that dst. Unfortunately, the code that allocates and fills this copy doesn't care about what type of flowi (flowi, flowi4, flowi6) gets passed. In multiple code paths (from raw_sendmsg, from TCP when replying to a FIN, in vxlan, geneve, and gre), the flowi that gets passed to xfrm is actually an on-stack flowi4, so we end up reading stuff from the stack past the end of the flowi4 struct. Since xfrm_dst->origin isn't used anywhere following commit ca116922afa8 ("xfrm: Eliminate "fl" and "pol" args to xfrm_bundle_ok()."), just get rid of it. xfrm_dst->partner isn't used either, so get rid of that too. Fixes: 9d6ec938019c ("ipv4: Use flowi4 in public route lookup interfaces.") Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
-rw-r--r--include/net/xfrm.h10
-rw-r--r--net/xfrm/xfrm_policy.c47
2 files changed, 0 insertions, 57 deletions
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 6793a30c66b1..7e7e2b0d2915 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -979,10 +979,6 @@ struct xfrm_dst {
struct flow_cache_object flo;
struct xfrm_policy *pols[XFRM_POLICY_TYPE_MAX];
int num_pols, num_xfrms;
-#ifdef CONFIG_XFRM_SUB_POLICY
- struct flowi *origin;
- struct xfrm_selector *partner;
-#endif
u32 xfrm_genid;
u32 policy_genid;
u32 route_mtu_cached;
@@ -998,12 +994,6 @@ static inline void xfrm_dst_destroy(struct xfrm_dst *xdst)
dst_release(xdst->route);
if (likely(xdst->u.dst.xfrm))
xfrm_state_put(xdst->u.dst.xfrm);
-#ifdef CONFIG_XFRM_SUB_POLICY
- kfree(xdst->origin);
- xdst->origin = NULL;
- kfree(xdst->partner);
- xdst->partner = NULL;
-#endif
}
#endif
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index b00a1d5a7f52..ed4e52d95172 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1797,43 +1797,6 @@ free_dst:
goto out;
}
-#ifdef CONFIG_XFRM_SUB_POLICY
-static int xfrm_dst_alloc_copy(void **target, const void *src, int size)
-{
- if (!*target) {
- *target = kmalloc(size, GFP_ATOMIC);
- if (!*target)
- return -ENOMEM;
- }
-
- memcpy(*target, src, size);
- return 0;
-}
-#endif
-
-static int xfrm_dst_update_parent(struct dst_entry *dst,
- const struct xfrm_selector *sel)
-{
-#ifdef CONFIG_XFRM_SUB_POLICY
- struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
- return xfrm_dst_alloc_copy((void **)&(xdst->partner),
- sel, sizeof(*sel));
-#else
- return 0;
-#endif
-}
-
-static int xfrm_dst_update_origin(struct dst_entry *dst,
- const struct flowi *fl)
-{
-#ifdef CONFIG_XFRM_SUB_POLICY
- struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
- return xfrm_dst_alloc_copy((void **)&(xdst->origin), fl, sizeof(*fl));
-#else
- return 0;
-#endif
-}
-
static int xfrm_expand_policies(const struct flowi *fl, u16 family,
struct xfrm_policy **pols,
int *num_pols, int *num_xfrms)
@@ -1905,16 +1868,6 @@ xfrm_resolve_and_create_bundle(struct xfrm_policy **pols, int num_pols,
xdst = (struct xfrm_dst *)dst;
xdst->num_xfrms = err;
- if (num_pols > 1)
- err = xfrm_dst_update_parent(dst, &pols[1]->selector);
- else
- err = xfrm_dst_update_origin(dst, fl);
- if (unlikely(err)) {
- dst_free(dst);
- XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTBUNDLECHECKERROR);
- return ERR_PTR(err);
- }
-
xdst->num_pols = num_pols;
memcpy(xdst->pols, pols, sizeof(struct xfrm_policy *) * num_pols);
xdst->policy_genid = atomic_read(&pols[0]->genid);