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authorVegard Nossum <vegard.nossum@oracle.com>2016-07-05 21:12:53 +0200
committerDavid S. Miller <davem@davemloft.net>2016-07-05 14:08:47 -0700
commitab58298cf459fcd4f588a401d36abf0bd2215b51 (patch)
tree58c77416b58a2b50ff681d1e3fde2444d17fdc98 /net
parentf5d6516120ee5c777fb7b1ba9d39031881ad511b (diff)
downloadlinux-ab58298cf459fcd4f588a401d36abf0bd2215b51.tar.gz
net: fix decnet rtnexthop parsing
dn_fib_count_nhs() could enter an infinite loop if nhp->rtnh_len == 0 (i.e. if userspace passes a malformed netlink message). Let's use the helpers from net/nexthop.h which take care of all this stuff. We can do exactly the same as e.g. fib_count_nexthops() and fib_get_nhs() from net/ipv4/fib_semantics.c. This fixes the softlockup for me. Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/decnet/dn_fib.c21
1 files changed, 12 insertions, 9 deletions
diff --git a/net/decnet/dn_fib.c b/net/decnet/dn_fib.c
index df4803437888..a796fc7cbc35 100644
--- a/net/decnet/dn_fib.c
+++ b/net/decnet/dn_fib.c
@@ -41,6 +41,7 @@
#include <net/dn_fib.h>
#include <net/dn_neigh.h>
#include <net/dn_dev.h>
+#include <net/nexthop.h>
#define RT_MIN_TABLE 1
@@ -150,14 +151,13 @@ static int dn_fib_count_nhs(const struct nlattr *attr)
struct rtnexthop *nhp = nla_data(attr);
int nhs = 0, nhlen = nla_len(attr);
- while(nhlen >= (int)sizeof(struct rtnexthop)) {
- if ((nhlen -= nhp->rtnh_len) < 0)
- return 0;
+ while (rtnh_ok(nhp, nhlen)) {
nhs++;
- nhp = RTNH_NEXT(nhp);
+ nhp = rtnh_next(nhp, &nhlen);
}
- return nhs;
+ /* leftover implies invalid nexthop configuration, discard it */
+ return nhlen > 0 ? 0 : nhs;
}
static int dn_fib_get_nhs(struct dn_fib_info *fi, const struct nlattr *attr,
@@ -167,21 +167,24 @@ static int dn_fib_get_nhs(struct dn_fib_info *fi, const struct nlattr *attr,
int nhlen = nla_len(attr);
change_nexthops(fi) {
- int attrlen = nhlen - sizeof(struct rtnexthop);
- if (attrlen < 0 || (nhlen -= nhp->rtnh_len) < 0)
+ int attrlen;
+
+ if (!rtnh_ok(nhp, nhlen))
return -EINVAL;
nh->nh_flags = (r->rtm_flags&~0xFF) | nhp->rtnh_flags;
nh->nh_oif = nhp->rtnh_ifindex;
nh->nh_weight = nhp->rtnh_hops + 1;
- if (attrlen) {
+ attrlen = rtnh_attrlen(nhp);
+ if (attrlen > 0) {
struct nlattr *gw_attr;
gw_attr = nla_find((struct nlattr *) (nhp + 1), attrlen, RTA_GATEWAY);
nh->nh_gw = gw_attr ? nla_get_le16(gw_attr) : 0;
}
- nhp = RTNH_NEXT(nhp);
+
+ nhp = rtnh_next(nhp, &nhlen);
} endfor_nexthops(fi);
return 0;