kernel/linux.git/net/ipv4/fib_semantics.c, branch linux-4.13.y

ipv4: fix NULL dereference in free_fib_info_rcu()

2017-08-16T00:07:52+00:00

If fi->fib_metrics could not be allocated in fib_create_info() we attempt to dereference a NULL pointer in free_fib_info_rcu() : m = fi->fib_metrics; if (m != &dst_default_metrics && atomic_dec_and_test(&m->refcnt)) kfree(m); Before my recent patch, we used to call kfree(NULL) and nothing wrong happened. Instead of using RCU to defer freeing while we are under memory stress, it seems better to take immediate action. This was reported by syzkaller team. Fixes: 3fb07daff8e9 ("ipv4: add reference counting to metrics") Signed-off-by: Eric Dumazet Reported-by: Dmitry Vyukov Signed-off-by: David S. Miller

ipv4: fib: Fix NULL pointer deref during fib_sync_down_dev()

2017-08-01T00:51:11+00:00

Michał reported a NULL pointer deref during fib_sync_down_dev() when unregistering a netdevice. The problem is that we don't check for 'in_dev' being NULL, which can happen in very specific cases. Usually routes are flushed upon NETDEV_DOWN sent in either the netdev or the inetaddr notification chains. However, if an interface isn't configured with any IP address, then it's possible for host routes to be flushed following NETDEV_UNREGISTER, after NULLing dev->ip_ptr in inetdev_destroy(). To reproduce: $ ip link add type dummy $ ip route add local 1.1.1.0/24 dev dummy0 $ ip link del dev dummy0 Fix this by checking for the presence of 'in_dev' before referencing it. Fixes: 982acb97560c ("ipv4: fib: Notify about nexthop status changes") Signed-off-by: Ido Schimmel Reported-by: Michał Mirosław Tested-by: Michał Mirosław Signed-off-by: David S. Miller

net, ipv4: convert fib_info.fib_clntref from atomic_t to refcount_t

2017-07-04T08:29:04+00:00

refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor Signed-off-by: David S. Miller

ipv4: mark DST_NOGC and remove the operation of dst_free()

2017-06-18T02:54:00+00:00

With the previous preparation patches, we are ready to get rid of the dst gc operation in ipv4 code and release dst based on refcnt only. So this patch adds DST_NOGC flag for all IPv4 dst and remove the calls to dst_free(). At this point, all dst created in ipv4 code do not use the dst gc anymore and will be destroyed at the point when refcnt drops to 0. Signed-off-by: Wei Wang Acked-by: Martin KaFai Lau Signed-off-by: David S. Miller

ipv4: call dst_dev_put() properly

2017-06-18T02:53:59+00:00

As the intend of this patch series is to completely remove dst gc, we need to call dst_dev_put() to release the reference to dst->dev when removing routes from fib because we won't keep the gc list anymore and will lose the dst pointer right after removing the routes. Without the gc list, there is no way to find all the dst's that have dst->dev pointing to the going-down dev. Hence, we are doing dst_dev_put() immediately before we lose the last reference of the dst from the routing code. The next dst_check() will trigger a route re-lookup to find another route (if there is any). Signed-off-by: Wei Wang Acked-by: Martin KaFai Lau Signed-off-by: David S. Miller

ipv4: take dst->__refcnt when caching dst in fib

2017-06-18T02:53:59+00:00

In IPv4 routing code, fib_nh and fib_nh_exception can hold pointers to struct rtable but they never increment dst->__refcnt. This leads to the need of the dst garbage collector because when user is done with this dst and calls dst_release(), it can only decrement dst->__refcnt and can not free the dst even it sees dst->__refcnt drops from 1 to 0 (unless DST_NOCACHE flag is set) because the routing code might still hold reference to it. And when the routing code tries to delete a route, it has to put the dst to the gc_list if dst->__refcnt is not yet 0 and have a gc thread running periodically to check on dst->__refcnt and finally to free dst when refcnt becomes 0. This patch increments dst->__refcnt when fib_nh/fib_nh_exception holds reference to this dst and properly release the dst when fib_nh/fib_nh_exception has been updated with a new dst. This patch is a preparation in order to fully get rid of dst gc later. Signed-off-by: Wei Wang Acked-by: Martin KaFai Lau Signed-off-by: David S. Miller

net: add extack arg to lwtunnel build state

2017-05-30T15:55:32+00:00

Pass extack arg down to lwtunnel_build_state and the build_state callbacks. Add messages for failures in lwtunnel_build_state, and add the extarg to nla_parse where possible in the build_state callbacks. Signed-off-by: David Ahern Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2017-05-27T00:46:35+00:00

Overlapping changes in drivers/net/phy/marvell.c, bug fix in 'net' restricting a HW workaround alongside cleanups in 'net-next'. Signed-off-by: David S. Miller

ipv4: add reference counting to metrics

2017-05-26T18:57:07+00:00

Andrey Konovalov reported crashes in ipv4_mtu() I could reproduce the issue with KASAN kernels, between 10.246.7.151 and 10.246.7.152 : 1) 20 concurrent netperf -t TCP_RR -H 10.246.7.152 -l 1000 & 2) At the same time run following loop : while : do ip ro add 10.246.7.152 dev eth0 src 10.246.7.151 mtu 1500 ip ro del 10.246.7.152 dev eth0 src 10.246.7.151 mtu 1500 done Cong Wang attempted to add back rt->fi in commit 82486aa6f1b9 ("ipv4: restore rt->fi for reference counting") but this proved to add some issues that were complex to solve. Instead, I suggested to add a refcount to the metrics themselves, being a standalone object (in particular, no reference to other objects) I tried to make this patch as small as possible to ease its backport, instead of being super clean. Note that we believe that only ipv4 dst need to take care of the metric refcount. But if this is wrong, this patch adds the basic infrastructure to extend this to other families. Many thanks to Julian Anastasov for reviewing this patch, and Cong Wang for his efforts on this problem. Fixes: 2860583fe840 ("ipv4: Kill rt->fi") Signed-off-by: Eric Dumazet Reported-by: Andrey Konovalov Reviewed-by: Julian Anastasov Acked-by: Cong Wang Signed-off-by: David S. Miller

net: ipv4: Add extack messages for route add failures

2017-05-22T16:12:20+00:00

Add messages for non-obvious errors (e.g, no need to add text for malloc failures or ENODEV failures). This mostly covers the annoying EINVAL errors Some message strings violate the 80-columns but searchable strings need to trump that rule. Signed-off-by: David Ahern Signed-off-by: David S. Miller