Skip to content

L
linux
Switch branch/tag
  1. 27 Feb, 2015 8 commits
    • subashab@codeaurora.org's avatar
      ping: Fix race in free in receive path · 688ba993
      subashab@codeaurora.org authored 
      [ Upstream commit fc752f1f ]

An exception is seen in ICMP ping receive path where the skb
destructor sock_rfree() tries to access a freed socket. This happens
because ping_rcv() releases socket reference with sock_put() and this
internally frees up the socket. Later icmp_rcv() will try to free the
skb and as part of this, skb destructor is called and which leads
to a kernel panic as the socket is freed already in ping_rcv().

-->|exception
-007|sk_mem_uncharge
-007|sock_rfree
-008|skb_release_head_state
-009|skb_release_all
-009|__kfree_skb
-010|kfree_skb
-011|icmp_rcv
-012|ip_local_deliver_finish

Fix this incorrect free by cloning this skb and processing this cloned
skb instead.

This patch was suggested by Eric Dumazet
Signed-off-by: default avatarSubash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      688ba993
    • Herbert Xu's avatar
      udp_diag: Fix socket skipping within chain · bd1f50c6
      Herbert Xu authored 
      [ Upstream commit 86f3cddb ]

While working on rhashtable walking I noticed that the UDP diag
dumping code is buggy.  In particular, the socket skipping within
a chain never happens, even though we record the number of sockets
that should be skipped.

As this code was supposedly copied from TCP, this patch does what
TCP does and resets num before we walk a chain.
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Acked-by: default avatarPavel Emelyanov <xemul@parallels.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      bd1f50c6
    • Hannes Frederic Sowa's avatar
      ipv4: try to cache dst_entries which would cause a redirect · 8c6dafeb
      Hannes Frederic Sowa authored 
      [ Upstream commit df4d9254 ]

Not caching dst_entries which cause redirects could be exploited by hosts
on the same subnet, causing a severe DoS attack. This effect aggravated
since commit f8864972 ("ipv4: fix dst race in sk_dst_get()").

Lookups causing redirects will be allocated with DST_NOCACHE set which
will force dst_release to free them via RCU.  Unfortunately waiting for
RCU grace period just takes too long, we can end up with >1M dst_entries
waiting to be released and the system will run OOM. rcuos threads cannot
catch up under high softirq load.

Attaching the flag to emit a redirect later on to the specific skb allows
us to cache those dst_entries thus reducing the pressure on allocation
and deallocation.

This issue was discovered by Marcelo Leitner.

Cc: Julian Anastasov <ja@ssi.bg>
Signed-off-by: default avatarMarcelo Leitner <mleitner@redhat.com>
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: default avatarJulian Anastasov <ja@ssi.bg>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      8c6dafeb
    • Daniel Borkmann's avatar
      net: sctp: fix slab corruption from use after free on INIT collisions · 727ab4c0
      Daniel Borkmann authored 
      [ Upstream commit 600ddd68 ]

When hitting an INIT collision case during the 4WHS with AUTH enabled, as
already described in detail in commit 1be9a950 ("net: sctp: inherit
auth_capable on INIT collisions"), it can happen that we occasionally
still remotely trigger the following panic on server side which seems to
have been uncovered after the fix from commit 1be9a950 ...

[  533.876389] BUG: unable to handle kernel paging request at 00000000ffffffff
[  533.913657] IP: [<ffffffff811ac385>] __kmalloc+0x95/0x230
[  533.940559] PGD 5030f2067 PUD 0
[  533.957104] Oops: 0000 [#1] SMP
[  533.974283] Modules linked in: sctp mlx4_en [...]
[  534.939704] Call Trace:
[  534.951833]  [<ffffffff81294e30>] ? crypto_init_shash_ops+0x60/0xf0
[  534.984213]  [<ffffffff81294e30>] crypto_init_shash_ops+0x60/0xf0
[  535.015025]  [<ffffffff8128c8ed>] __crypto_alloc_tfm+0x6d/0x170
[  535.045661]  [<ffffffff8128d12c>] crypto_alloc_base+0x4c/0xb0
[  535.074593]  [<ffffffff8160bd42>] ? _raw_spin_lock_bh+0x12/0x50
[  535.105239]  [<ffffffffa0418c11>] sctp_inet_listen+0x161/0x1e0 [sctp]
[  535.138606]  [<ffffffff814e43bd>] SyS_listen+0x9d/0xb0
[  535.166848]  [<ffffffff816149a9>] system_call_fastpath+0x16/0x1b

... or depending on the the application, for example this one:

[ 1370.026490] BUG: unable to handle kernel paging request at 00000000ffffffff
[ 1370.026506] IP: [<ffffffff811ab455>] kmem_cache_alloc+0x75/0x1d0
[ 1370.054568] PGD 633c94067 PUD 0
[ 1370.070446] Oops: 0000 [#1] SMP
[ 1370.085010] Modules linked in: sctp kvm_amd kvm [...]
[ 1370.963431] Call Trace:
[ 1370.974632]  [<ffffffff8120f7cf>] ? SyS_epoll_ctl+0x53f/0x960
[ 1371.000863]  [<ffffffff8120f7cf>] SyS_epoll_ctl+0x53f/0x960
[ 1371.027154]  [<ffffffff812100d3>] ? anon_inode_getfile+0xd3/0x170
[ 1371.054679]  [<ffffffff811e3d67>] ? __alloc_fd+0xa7/0x130
[ 1371.080183]  [<ffffffff816149a9>] system_call_fastpath+0x16/0x1b

With slab debugging enabled, we can see that the poison has been overwritten:

[  669.826368] BUG kmalloc-128 (Tainted: G        W     ): Poison overwritten
[  669.826385] INFO: 0xffff880228b32e50-0xffff880228b32e50. First byte 0x6a instead of 0x6b
[  669.826414] INFO: Allocated in sctp_auth_create_key+0x23/0x50 [sctp] age=3 cpu=0 pid=18494
[  669.826424]  __slab_alloc+0x4bf/0x566
[  669.826433]  __kmalloc+0x280/0x310
[  669.826453]  sctp_auth_create_key+0x23/0x50 [sctp]
[  669.826471]  sctp_auth_asoc_create_secret+0xcb/0x1e0 [sctp]
[  669.826488]  sctp_auth_asoc_init_active_key+0x68/0xa0 [sctp]
[  669.826505]  sctp_do_sm+0x29d/0x17c0 [sctp] [...]
[  669.826629] INFO: Freed in kzfree+0x31/0x40 age=1 cpu=0 pid=18494
[  669.826635]  __slab_free+0x39/0x2a8
[  669.826643]  kfree+0x1d6/0x230
[  669.826650]  kzfree+0x31/0x40
[  669.826666]  sctp_auth_key_put+0x19/0x20 [sctp]
[  669.826681]  sctp_assoc_update+0x1ee/0x2d0 [sctp]
[  669.826695]  sctp_do_sm+0x674/0x17c0 [sctp]

Since this only triggers in some collision-cases with AUTH, the problem at
heart is that sctp_auth_key_put() on asoc->asoc_shared_key is called twice
when having refcnt 1, once directly in sctp_assoc_update() and yet again
from within sctp_auth_asoc_init_active_key() via sctp_assoc_update() on
the already kzfree'd memory, which is also consistent with the observation
of the poison decrease from 0x6b to 0x6a (note: the overwrite is detected
at a later point in time when poison is checked on new allocation).

Reference counting of auth keys revisited:

Shared keys for AUTH chunks are being stored in endpoints and associations
in endpoint_shared_keys list. On endpoint creation, a null key is being
added; on association creation, all endpoint shared keys are being cached
and thus cloned over to the association. struct sctp_shared_key only holds
a pointer to the actual key bytes, that is, struct sctp_auth_bytes which
keeps track of users internally through refcounting. Naturally, on assoc
or enpoint destruction, sctp_shared_key are being destroyed directly and
the reference on sctp_auth_bytes dropped.

User space can add keys to either list via setsockopt(2) through struct
sctp_authkey and by passing that to sctp_auth_set_key() which replaces or
adds a new auth key. There, sctp_auth_create_key() creates a new sctp_auth_bytes
with refcount 1 and in case of replacement drops the reference on the old
sctp_auth_bytes. A key can be set active from user space through setsockopt()
on the id via sctp_auth_set_active_key(), which iterates through either
endpoint_shared_keys and in case of an assoc, invokes (one of various places)
sctp_auth_asoc_init_active_key().

sctp_auth_asoc_init_active_key() computes the actual secret from local's
and peer's random, hmac and shared key parameters and returns a new key
directly as sctp_auth_bytes, that is asoc->asoc_shared_key, plus drops
the reference if there was a previous one. The secret, which where we
eventually double drop the ref comes from sctp_auth_asoc_set_secret() with
intitial refcount of 1, which also stays unchanged eventually in
sctp_assoc_update(). This key is later being used for crypto layer to
set the key for the hash in crypto_hash_setkey() from sctp_auth_calculate_hmac().

To close the loop: asoc->asoc_shared_key is freshly allocated secret
material and independant of the sctp_shared_key management keeping track
of only shared keys in endpoints and assocs. Hence, also commit 4184b2a7
("net: sctp: fix memory leak in auth key management") is independant of
this bug here since it concerns a different layer (though same structures
being used eventually). asoc->asoc_shared_key is reference dropped correctly
on assoc destruction in sctp_association_free() and when active keys are
being replaced in sctp_auth_asoc_init_active_key(), it always has a refcount
of 1. Hence, it's freed prematurely in sctp_assoc_update(). Simple fix is
to remove that sctp_auth_key_put() from there which fixes these panics.

Fixes: 730fc3d0 ("[SCTP]: Implete SCTP-AUTH parameter processing")
Signed-off-by: default avatarDaniel Borkmann <dborkman@redhat.com>
Acked-by: default avatarVlad Yasevich <vyasevich@gmail.com>
Acked-by: default avatarNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      727ab4c0
    • Eric Dumazet's avatar
      netxen: fix netxen_nic_poll() logic · e98d2751
      Eric Dumazet authored 
      [ Upstream commit 6088beef ]

NAPI poll logic now enforces that a poller returns exactly the budget
when it wants to be called again.

If a driver limits TX completion, it has to return budget as well when
the limit is hit, not the number of received packets.
Reported-and-tested-by: default avatarMike Galbraith <umgwanakikbuti@gmail.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Fixes: d75b1ade ("net: less interrupt masking in NAPI")
Cc: Manish Chopra <manish.chopra@qlogic.com>
Acked-by: default avatarManish Chopra <manish.chopra@qlogic.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      e98d2751
    • Hagen Paul Pfeifer's avatar
      ipv6: stop sending PTB packets for MTU < 1280 · fa3f55df
      Hagen Paul Pfeifer authored 
      [ Upstream commit 9d289715 ]

Reduce the attack vector and stop generating IPv6 Fragment Header for
paths with an MTU smaller than the minimum required IPv6 MTU
size (1280 byte) - called atomic fragments.

See IETF I-D "Deprecating the Generation of IPv6 Atomic Fragments" [1]
for more information and how this "feature" can be misused.

[1] https://tools.ietf.org/html/draft-ietf-6man-deprecate-atomfrag-generation-00Signed-off-by: default avatarFernando Gont <fgont@si6networks.com>
Signed-off-by: default avatarHagen Paul Pfeifer <hagen@jauu.net>
Acked-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      fa3f55df
    • Eric Dumazet's avatar
      net: rps: fix cpu unplug · 06b5ff9f
      Eric Dumazet authored 
      [ Upstream commit ac64da0b ]

softnet_data.input_pkt_queue is protected by a spinlock that
we must hold when transferring packets from victim queue to an active
one. This is because other cpus could still be trying to enqueue packets
into victim queue.

A second problem is that when we transfert the NAPI poll_list from
victim to current cpu, we absolutely need to special case the percpu
backlog, because we do not want to add complex locking to protect
process_queue : Only owner cpu is allowed to manipulate it, unless cpu
is offline.

Based on initial patch from Prasad Sodagudi & Subash Abhinov
Kasiviswanathan.

This version is better because we do not slow down packet processing,
only make migration safer.
Reported-by: default avatarPrasad Sodagudi <psodagud@codeaurora.org>
Reported-by: default avatarSubash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Tom Herbert <therbert@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      06b5ff9f
    • Willem de Bruijn's avatar
      ip: zero sockaddr returned on error queue · 1d480edb
      Willem de Bruijn authored 
      [ Upstream commit f812116b ]

The sockaddr is returned in IP(V6)_RECVERR as part of errhdr. That
structure is defined and allocated on the stack as

    struct {
            struct sock_extended_err ee;
            struct sockaddr_in(6)    offender;
    } errhdr;

The second part is only initialized for certain SO_EE_ORIGIN values.
Always initialize it completely.

An MTU exceeded error on a SOCK_RAW/IPPROTO_RAW is one example that
would return uninitialized bytes.
Signed-off-by: default avatarWillem de Bruijn <willemb@google.com>

----

Also verified that there is no padding between errhdr.ee and
errhdr.offender that could leak additional kernel data.
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      1d480edb
  3. 11 Feb, 2015 19 commits
  5. 06 Feb, 2015 13 commits
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7