From 4bed72e4f5502ea3322f0a00794815fa58951abe Mon Sep 17 00:00:00 2001 From: YOSHIFUJI Hideaki Date: Tue, 27 May 2008 17:37:49 +0900 Subject: [PATCH] [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 --- include/net/addrconf.h | 22 ++++++++++ net/ipv6/addrconf.c | 97 ++++++++++++++++++++++-------------------- net/ipv6/route.c | 12 ++---- 3 files changed, 75 insertions(+), 56 deletions(-) diff --git a/include/net/addrconf.h b/include/net/addrconf.h index 0a2f0372df3..bbd3d583c6e 100644 --- a/include/net/addrconf.h +++ b/include/net/addrconf.h @@ -94,6 +94,28 @@ extern void addrconf_join_solict(struct net_device *dev, 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 c3b20c5afa3..147588f4c7c 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -731,8 +731,13 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp) 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 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len) __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 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len) * 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 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len) 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 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len) 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 @@ static int inet6_addr_add(struct net *net, int ifindex, struct in6_addr *pfx, int scope; u32 flags; clock_t expires; + unsigned long timeout; ASSERT_RTNL(); @@ -2055,22 +2055,23 @@ static int inet6_addr_add(struct net *net, int ifindex, struct in6_addr *pfx, 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 @@ static int inet6_addr_modify(struct inet6_ifaddr *ifp, u8 ifa_flags, { 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 48534c6c073..220cffe9e63 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -446,7 +446,7 @@ int rt6_route_rcv(struct net_device *dev, u8 *opt, int len, 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 @@ int rt6_route_rcv(struct net_device *dev, u8 *opt, int len, 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 @@ int rt6_route_rcv(struct net_device *dev, u8 *opt, int len, (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; -- 2.20.1