linux-toradex.git/net/ipv4/fib_frontend.c, branch v4.4.126

ipv4: Fix use-after-free when flushing FIB tables

2018-01-02T19:33:26+00:00

[ Upstream commit b4681c2829e24943aadd1a7bb3a30d41d0a20050 ]

Since commit 0ddcf43d5d4a ("ipv4: FIB Local/MAIN table collapse") the
local table uses the same trie allocated for the main table when custom
rules are not in use.

When a net namespace is dismantled, the main table is flushed and freed
(via an RCU callback) before the local table. In case the callback is
invoked before the local table is iterated, a use-after-free can occur.

Fix this by iterating over the FIB tables in reverse order, so that the
main table is always freed after the local table.

v3: Reworded comment according to Alex's suggestion.
v2: Add a comment to make the fix more explicit per Dave's and Alex's
feedback.

Fixes: 0ddcf43d5d4a ("ipv4: FIB Local/MAIN table collapse")
Signed-off-by: Ido Schimmel 
Reported-by: Fengguang Wu 
Acked-by: Alexander Duyck 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv4: initialize fib_trie prior to register_netdev_notifier call.

2017-08-11T16:08:52+00:00

[ Upstream commit 8799a221f5944a7d74516ecf46d58c28ec1d1f75 ]

Net stack initialization currently initializes fib-trie after the
first call to netdevice_notifier() call. In fact fib_trie initialization
needs to happen before first rtnl_register(). It does not cause any problem
since there are no devices UP at this moment, but trying to bring 'lo'
UP at initialization would make this assumption wrong and exposes the issue.

Fixes following crash

 Call Trace:
  ? alternate_node_alloc+0x76/0xa0
  fib_table_insert+0x1b7/0x4b0
  fib_magic.isra.17+0xea/0x120
  fib_add_ifaddr+0x7b/0x190
  fib_netdev_event+0xc0/0x130
  register_netdevice_notifier+0x1c1/0x1d0
  ip_fib_init+0x72/0x85
  ip_rt_init+0x187/0x1e9
  ip_init+0xe/0x1a
  inet_init+0x171/0x26c
  ? ipv4_offload_init+0x66/0x66
  do_one_initcall+0x43/0x160
  kernel_init_freeable+0x191/0x219
  ? rest_init+0x80/0x80
  kernel_init+0xe/0x150
  ret_from_fork+0x22/0x30
 Code: f6 46 23 04 74 86 4c 89 f7 e8 ae 45 01 00 49 89 c7 4d 85 ff 0f 85 7b ff ff ff 31 db eb 08 4c 89 ff e8 16 47 01 00 48 8b 44 24 38 <45> 8b 6e 14 4d 63 76 74 48 89 04 24 0f 1f 44 00 00 48 83 c4 08
 RIP: kmem_cache_alloc+0xcf/0x1c0 RSP: ffff9b1500017c28
 CR2: 0000000000000014

Fixes: 7b1a74fdbb9e ("[NETNS]: Refactor fib initialization so it can handle multiple namespaces.")
Fixes: 7f9b80529b8a ("[IPV4]: fib hash|trie initialization")

Signed-off-by: Mahesh Bandewar 
Acked-by: "Eric W. Biederman" 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: Improve handling of failures on link and route dumps

2017-06-07T10:05:58+00:00

[ Upstream commit f6c5775ff0bfa62b072face6bf1d40f659f194b2 ]

In general, rtnetlink dumps do not anticipate failure to dump a single
object (e.g., link or route) on a single pass. As both route and link
objects have grown via more attributes, that is no longer a given.

netlink dumps can handle a failure if the dump function returns an
error; specifically, netlink_dump adds the return code to the response
if it is <= 0 so userspace is notified of the failure. The missing
piece is the rtnetlink dump functions returning the error.

Fix route and link dump functions to return the errors if no object is
added to an skb (detected by skb->len != 0). IPv6 route dumps
(rt6_dump_route) already return the error; this patch updates IPv4 and
link dumps. Other dump functions may need to be ajusted as well.

Reported-by: Jan Moskyto Matejka 
Signed-off-by: David Ahern 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv4: provide stronger user input validation in nl_fib_input()

2017-03-30T07:35:14+00:00

[ Upstream commit c64c0b3cac4c5b8cb093727d2c19743ea3965c0b ]

Alexander reported a KMSAN splat caused by reads of uninitialized
field (tb_id_in) from user provided struct fib_result_nl

It turns out nl_fib_input() sanity tests on user input is a bit
wrong :

User can pretend nlh->nlmsg_len is big enough, but provide
at sendmsg() time a too small buffer.

Reported-by: Alexander Potapenko 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv4: Do not allow MAIN to be alias for new LOCAL w/ custom rules

2017-01-15T12:41:35+00:00

[ Upstream commit 5350d54f6cd12eaff623e890744c79b700bd3f17 ]

In the case of custom rules being present we need to handle the case of the
LOCAL table being intialized after the new rule has been added.  To address
that I am adding a new check so that we can make certain we don't use an
alias of MAIN for LOCAL when allocating a new table.

Fixes: 0ddcf43d5d4a ("ipv4: FIB Local/MAIN table collapse")
Reported-by: Oliver Brunel 
Signed-off-by: Alexander Duyck 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv4/fib: don't warn when primary address is missing if in_dev is dead

2016-05-19T00:06:36+00:00

[ Upstream commit 391a20333b8393ef2e13014e6e59d192c5594471 ]

After commit fbd40ea0180a ("ipv4: Don't do expensive useless work
during inetdev destroy.") when deleting an interface,
fib_del_ifaddr() can be executed without any primary address
present on the dead interface.

The above is safe, but triggers some "bug: prim == NULL" warnings.

This commit avoids warning if the in_dev is dead

Signed-off-by: Paolo Abeni 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv4: initialize flowi4_flags before calling fib_lookup()

2016-04-20T06:42:05+00:00

[ Upstream commit 4cfc86f3dae6ca38ed49cdd78f458a03d4d87992 ]

Field fl4.flowi4_flags is not initialized in fib_compute_spec_dst()
before calling fib_lookup(), which means fib_table_lookup() is
using non-deterministic data at this line:

	if (!(flp->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF)) {

Fix by initializing the entire fl4 structure, which will prevent
similar issues as fields are added in the future by ensuring that
all fields are initialized to zero unless explicitly initialized
to another value.

Fixes: 58189ca7b2741 ("net: Fix vti use case with oif in dst lookups")
Suggested-by: David Ahern 
Signed-off-by: Lance Richardson 
Acked-by: David Ahern 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv4: Don't do expensive useless work during inetdev destroy.

2016-04-20T06:42:03+00:00

[ Upstream commit fbd40ea0180a2d328c5adc61414dc8bab9335ce2 ]

When an inetdev is destroyed, every address assigned to the interface
is removed.  And in this scenerio we do two pointless things which can
be very expensive if the number of assigned interfaces is large:

1) Address promotion.  We are deleting all addresses, so there is no
   point in doing this.

2) A full nf conntrack table purge for every address.  We only need to
   do this once, as is already caught by the existing
   masq_dev_notifier so masq_inet_event() can skip this.

Reported-by: Solar Designer 
Signed-off-by: David S. Miller 
Tested-by: Cyrill Gorcunov 
Signed-off-by: Greg Kroah-Hartman

net: Flush local routes when device changes vrf association

2015-12-14T04:58:44+00:00

The VRF driver cycles netdevs when an interface is enslaved or released:
the down event is used to flush neighbor and route tables and the up
event (if the interface was already up) effectively moves local and
connected routes to the proper table.

As of 4f823defdd5b the local route is left hanging around after a link
down, so when a netdev is moved from one VRF to another (or released
from a VRF altogether) local routes are left in the wrong table.

Fix by handling the NETDEV_CHANGEUPPER event. When the upper dev is
an L3mdev then call fib_disable_ip to flush all routes, local ones
to.

Fixes: 4f823defdd5b ("ipv4: fix to not remove local route on link down")
Cc: Julian Anastasov 
Signed-off-by: David Ahern 
Signed-off-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller

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

2015-11-03T18:41:45+00:00

Minor overlapping changes in net/ipv4/ipmr.c, in 'net' we were
fixing the "BH-ness" of the counter bumps whilst in 'net-next'
the functions were modified to take an explicit 'net' parameter.

Signed-off-by: David S. Miller