[IPV6] ADDRCONF: Allow longer lifetime on 64bit archs.
- Allow longer lifetimes (>= 0x7fffffff/HZ) on 64bit archs
by using unsigned long.
- Shadow this arithmetic overflow workaround by introducing
helper functions: addrconf_timeout_fixup() and
addrconf_finite_timeout().
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index 0a2f037..bbd3d58 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -94,6 +94,28 @@
extern void addrconf_leave_solict(struct inet6_dev *idev,
struct in6_addr *addr);
+static inline unsigned long addrconf_timeout_fixup(u32 timeout,
+ unsigned unit)
+{
+ if (timeout == 0xffffffff)
+ return ~0UL;
+
+ /*
+ * Avoid arithmetic overflow.
+ * Assuming unit is constant and non-zero, this "if" statement
+ * will go away on 64bit archs.
+ */
+ if (0xfffffffe > LONG_MAX / unit && timeout > LONG_MAX / unit)
+ return LONG_MAX / unit;
+
+ return timeout;
+}
+
+static inline int addrconf_finite_timeout(unsigned long timeout)
+{
+ return ~timeout;
+}
+
/*
* IPv6 Address Label subsystem (addrlabel.c)
*/
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index c3b20c5..147588f 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -731,8 +731,13 @@
onlink = -1;
spin_lock(&ifa->lock);
- lifetime = min_t(unsigned long,
- ifa->valid_lft, 0x7fffffffUL/HZ);
+
+ lifetime = addrconf_timeout_fixup(ifa->valid_lft, HZ);
+ /*
+ * Note: Because this address is
+ * not permanent, lifetime <
+ * LONG_MAX / HZ here.
+ */
if (time_before(expires,
ifa->tstamp + lifetime * HZ))
expires = ifa->tstamp + lifetime * HZ;
@@ -1722,7 +1727,6 @@
__u32 valid_lft;
__u32 prefered_lft;
int addr_type;
- unsigned long rt_expires;
struct inet6_dev *in6_dev;
pinfo = (struct prefix_info *) opt;
@@ -1764,28 +1768,23 @@
* 2) Configure prefixes with the auto flag set
*/
- if (valid_lft == INFINITY_LIFE_TIME)
- rt_expires = ~0UL;
- else if (valid_lft >= 0x7FFFFFFF/HZ) {
+ if (pinfo->onlink) {
+ struct rt6_info *rt;
+ unsigned long rt_expires;
+
/* Avoid arithmetic overflow. Really, we could
* save rt_expires in seconds, likely valid_lft,
* but it would require division in fib gc, that it
* not good.
*/
- rt_expires = 0x7FFFFFFF - (0x7FFFFFFF % HZ);
- } else
- rt_expires = valid_lft * HZ;
+ if (HZ > USER_HZ)
+ rt_expires = addrconf_timeout_fixup(valid_lft, HZ);
+ else
+ rt_expires = addrconf_timeout_fixup(valid_lft, USER_HZ);
- /*
- * We convert this (in jiffies) to clock_t later.
- * Avoid arithmetic overflow there as well.
- * Overflow can happen only if HZ < USER_HZ.
- */
- if (HZ < USER_HZ && ~rt_expires && rt_expires > 0x7FFFFFFF / USER_HZ)
- rt_expires = 0x7FFFFFFF / USER_HZ;
+ if (addrconf_finite_timeout(rt_expires))
+ rt_expires *= HZ;
- if (pinfo->onlink) {
- struct rt6_info *rt;
rt = rt6_lookup(dev_net(dev), &pinfo->prefix, NULL,
dev->ifindex, 1);
@@ -1794,7 +1793,7 @@
if (valid_lft == 0) {
ip6_del_rt(rt);
rt = NULL;
- } else if (~rt_expires) {
+ } else if (addrconf_finite_timeout(rt_expires)) {
/* not infinity */
rt->rt6i_expires = jiffies + rt_expires;
rt->rt6i_flags |= RTF_EXPIRES;
@@ -1803,9 +1802,9 @@
rt->rt6i_expires = 0;
}
} else if (valid_lft) {
- int flags = RTF_ADDRCONF | RTF_PREFIX_RT;
clock_t expires = 0;
- if (~rt_expires) {
+ int flags = RTF_ADDRCONF | RTF_PREFIX_RT;
+ if (addrconf_finite_timeout(rt_expires)) {
/* not infinity */
flags |= RTF_EXPIRES;
expires = jiffies_to_clock_t(rt_expires);
@@ -2036,6 +2035,7 @@
int scope;
u32 flags;
clock_t expires;
+ unsigned long timeout;
ASSERT_RTNL();
@@ -2055,22 +2055,23 @@
scope = ipv6_addr_scope(pfx);
- if (valid_lft == INFINITY_LIFE_TIME) {
- ifa_flags |= IFA_F_PERMANENT;
- flags = 0;
- expires = 0;
- } else {
- if (valid_lft >= 0x7FFFFFFF/HZ)
- valid_lft = 0x7FFFFFFF/HZ;
+ timeout = addrconf_timeout_fixup(valid_lft, HZ);
+ if (addrconf_finite_timeout(timeout)) {
+ expires = jiffies_to_clock_t(timeout * HZ);
+ valid_lft = timeout;
flags = RTF_EXPIRES;
- expires = jiffies_to_clock_t(valid_lft * HZ);
+ } else {
+ expires = 0;
+ flags = 0;
+ ifa_flags |= IFA_F_PERMANENT;
}
- if (prefered_lft == 0)
- ifa_flags |= IFA_F_DEPRECATED;
- else if ((prefered_lft >= 0x7FFFFFFF/HZ) &&
- (prefered_lft != INFINITY_LIFE_TIME))
- prefered_lft = 0x7FFFFFFF/HZ;
+ timeout = addrconf_timeout_fixup(prefered_lft, HZ);
+ if (addrconf_finite_timeout(timeout)) {
+ if (timeout == 0)
+ ifa_flags |= IFA_F_DEPRECATED;
+ prefered_lft = timeout;
+ }
ifp = ipv6_add_addr(idev, pfx, plen, scope, ifa_flags);
@@ -3175,26 +3176,28 @@
{
u32 flags;
clock_t expires;
+ unsigned long timeout;
if (!valid_lft || (prefered_lft > valid_lft))
return -EINVAL;
- if (valid_lft == INFINITY_LIFE_TIME) {
- ifa_flags |= IFA_F_PERMANENT;
- flags = 0;
- expires = 0;
- } else {
- if (valid_lft >= 0x7FFFFFFF/HZ)
- valid_lft = 0x7FFFFFFF/HZ;
+ timeout = addrconf_timeout_fixup(valid_lft, HZ);
+ if (addrconf_finite_timeout(timeout)) {
+ expires = jiffies_to_clock_t(timeout * HZ);
+ valid_lft = timeout;
flags = RTF_EXPIRES;
- expires = jiffies_to_clock_t(valid_lft * HZ);
+ } else {
+ expires = 0;
+ flags = 0;
+ ifa_flags |= IFA_F_PERMANENT;
}
- if (prefered_lft == 0)
- ifa_flags |= IFA_F_DEPRECATED;
- else if ((prefered_lft >= 0x7FFFFFFF/HZ) &&
- (prefered_lft != INFINITY_LIFE_TIME))
- prefered_lft = 0x7FFFFFFF/HZ;
+ timeout = addrconf_timeout_fixup(prefered_lft, HZ);
+ if (addrconf_finite_timeout(timeout)) {
+ if (timeout == 0)
+ ifa_flags |= IFA_F_DEPRECATED;
+ prefered_lft = timeout;
+ }
spin_lock_bh(&ifp->lock);
ifp->flags = (ifp->flags & ~(IFA_F_DEPRECATED | IFA_F_PERMANENT | IFA_F_NODAD | IFA_F_HOMEADDRESS)) | ifa_flags;
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 48534c6..220cffe 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -446,7 +446,7 @@
struct route_info *rinfo = (struct route_info *) opt;
struct in6_addr prefix_buf, *prefix;
unsigned int pref;
- u32 lifetime;
+ unsigned long lifetime;
struct rt6_info *rt;
if (len < sizeof(struct route_info)) {
@@ -472,13 +472,7 @@
if (pref == ICMPV6_ROUTER_PREF_INVALID)
pref = ICMPV6_ROUTER_PREF_MEDIUM;
- lifetime = ntohl(rinfo->lifetime);
- if (lifetime == 0xffffffff) {
- /* infinity */
- } else if (lifetime > 0x7fffffff/HZ - 1) {
- /* Avoid arithmetic overflow */
- lifetime = 0x7fffffff/HZ - 1;
- }
+ lifetime = addrconf_timeout_fixup(ntohl(rinfo->lifetime), HZ);
if (rinfo->length == 3)
prefix = (struct in6_addr *)rinfo->prefix;
@@ -506,7 +500,7 @@
(rt->rt6i_flags & ~RTF_PREF_MASK) | RTF_PREF(pref);
if (rt) {
- if (lifetime == 0xffffffff) {
+ if (!addrconf_finite_timeout(lifetime)) {
rt->rt6i_flags &= ~RTF_EXPIRES;
} else {
rt->rt6i_expires = jiffies + HZ * lifetime;
