linux-stable.git/net/core/dev.c, branch linux-4.15.y

net: fool proof dev_valid_name()

2018-04-12T10:31:18+00:00

[ Upstream commit a9d48205d0aedda021fc3728972a9e9934c2b9de ]

We want to use dev_valid_name() to validate tunnel names,
so better use strnlen(name, IFNAMSIZ) than strlen(name) to make
sure to not upset KASAN.

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

net: fix possible out-of-bound read in skb_network_protocol()

2018-04-12T10:31:16+00:00

[ Upstream commit 1dfe82ebd7d8fd43dba9948fdfb31f145014baa0 ]

skb mac header is not necessarily set at the time skb_network_protocol()
is called. Use skb->data instead.

BUG: KASAN: slab-out-of-bounds in skb_network_protocol+0x46b/0x4b0 net/core/dev.c:2739
Read of size 2 at addr ffff8801b3097a0b by task syz-executor5/14242

CPU: 1 PID: 14242 Comm: syz-executor5 Not tainted 4.16.0-rc6+ #280
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x24d lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report+0x23c/0x360 mm/kasan/report.c:412
 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/report.c:443
 skb_network_protocol+0x46b/0x4b0 net/core/dev.c:2739
 harmonize_features net/core/dev.c:2924 [inline]
 netif_skb_features+0x509/0x9b0 net/core/dev.c:3011
 validate_xmit_skb+0x81/0xb00 net/core/dev.c:3084
 validate_xmit_skb_list+0xbf/0x120 net/core/dev.c:3142
 packet_direct_xmit+0x117/0x790 net/packet/af_packet.c:256
 packet_snd net/packet/af_packet.c:2944 [inline]
 packet_sendmsg+0x3aed/0x60b0 net/packet/af_packet.c:2969
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:639
 ___sys_sendmsg+0x767/0x8b0 net/socket.c:2047
 __sys_sendmsg+0xe5/0x210 net/socket.c:2081

Fixes: 19acc327258a ("gso: Handle Trans-Ether-Bridging protocol in skb_network_protocol()")
Signed-off-by: Eric Dumazet 
Cc: Pravin B Shelar 
Reported-by: Reported-by: syzbot 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: use skb_to_full_sk() in skb_update_prio()

2018-03-31T16:05:43+00:00

[ Upstream commit 4dcb31d4649df36297296b819437709f5407059c ]

Andrei Vagin reported a KASAN: slab-out-of-bounds error in
skb_update_prio()

Since SYNACK might be attached to a request socket, we need to
get back to the listener socket.
Since this listener is manipulated without locks, add const
qualifiers to sock_cgroup_prioidx() so that the const can also
be used in skb_update_prio()

Also add the const qualifier to sock_cgroup_classid() for consistency.

Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of listener")
Signed-off-by: Eric Dumazet 
Reported-by: Andrei Vagin 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: fix race on decreasing number of TX queues

2018-03-09T06:47:34+00:00

[ Upstream commit ac5b70198adc25c73fba28de4f78adcee8f6be0b ]

netif_set_real_num_tx_queues() can be called when netdev is up.
That usually happens when user requests change of number of
channels/rings with ethtool -L.  The procedure for changing
the number of queues involves resetting the qdiscs and setting
dev->num_tx_queues to the new value.  When the new value is
lower than the old one, extra care has to be taken to ensure
ordering of accesses to the number of queues vs qdisc reset.

Currently the queues are reset before new dev->num_tx_queues
is assigned, leaving a window of time where packets can be
enqueued onto the queues going down, leading to a likely
crash in the drivers, since most drivers don't check if TX
skbs are assigned to an active queue.

Fixes: e6484930d7c7 ("net: allocate tx queues in register_netdevice")
Signed-off-by: Jakub Kicinski 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: avoid skb_warn_bad_offload on IS_ERR

2018-02-25T10:15:41+00:00

commit 8d74e9f88d65af8bb2e095aff506aa6eac755ada upstream.

skb_warn_bad_offload warns when packets enter the GSO stack that
require skb_checksum_help or vice versa. Do not warn on arbitrary
bad packets. Packet sockets can craft many. Syzkaller was able to
demonstrate another one with eth_type games.

In particular, suppress the warning when segmentation returns an
error, which is for reasons other than checksum offload.

See also commit 36c92474498a ("net: WARN if skb_checksum_help() is
called on skb requiring segmentation") for context on this warning.

Signed-off-by: Willem de Bruijn 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: qdisc_pkt_len_init() should be more robust

2018-01-22T21:00:05+00:00

Without proper validation of DODGY packets, we might very well
feed qdisc_pkt_len_init() with invalid GSO packets.

tcp_hdrlen() might access out-of-bound data, so let's use
skb_header_pointer() and proper checks.

Whole story is described in commit d0c081b49137 ("flow_dissector:
properly cap thoff field")

We have the goal of validating DODGY packets earlier in the stack,
so we might very well revert this fix in the future.

Signed-off-by: Eric Dumazet 
Cc: Willem de Bruijn 
Cc: Jason Wang 
Reported-by: syzbot+9da69ebac7dddd804552@syzkaller.appspotmail.com
Acked-by: Jason Wang 
Signed-off-by: David S. Miller

Revert "net: core: dev_get_valid_name is now the same as dev_alloc_name_ns"

2018-01-02T16:50:12+00:00

This reverts commit 87c320e51519a83c496ab7bfb4e96c8f9c001e89.

Changing the error return code in some situations turns out to
be harmful in practice.  In particular Michael Ellerman reports
that DHCP fails on his powerpc machines, and this revert gets
things working again.

Johannes Berg agrees that this revert is the best course of
action for now.

Fixes: 029b6d140550 ("Revert "net: core: maybe return -EEXIST in __dev_alloc_name"")
Reported-by: Michael Ellerman 
Signed-off-by: David S. Miller

xdp: linearize skb in netif_receive_generic_xdp()

2017-12-15T13:34:36+00:00

In netif_receive_generic_xdp(), it is necessary to linearize all
nonlinear skb. However, in current implementation, skb with
troom <= 0 are not linearized. This patch fixes this by calling
skb_linearize() for all nonlinear skb.

Fixes: de8f3a83b0a0 ("bpf: add meta pointer for direct access")
Signed-off-by: Song Liu 
Acked-by: Martin KaFai Lau 
Cc: Daniel Borkmann 
Cc: Alexei Starovoitov 
Signed-off-by: Daniel Borkmann

Revert "net: core: maybe return -EEXIST in __dev_alloc_name"

2017-12-05T16:29:48+00:00

This reverts commit d6f295e9def0; some userspace (in the case
we noticed it's wpa_supplicant), is relying on the current
error code to determine that a fixed name interface already
exists.

Reported-by: Jouni Malinen 
Signed-off-by: Johannes Berg 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

2017-11-23T17:33:01+00:00

Daniel Borkmann says:

====================
pull-request: bpf 2017-11-23

The following pull-request contains BPF updates for your *net* tree.

The main changes are:

1) Several BPF offloading fixes, from Jakub. Among others:

    - Limit offload to cls_bpf and XDP program types only.
    - Move device validation into the driver and don't make
      any assumptions about the device in the classifier due
      to shared blocks semantics.
    - Don't pass offloaded XDP program into the driver when
      it should be run in native XDP instead. Offloaded ones
      are not JITed for the host in such cases.
    - Don't destroy device offload state when moved to
      another namespace.
    - Revert dumping offload info into user space for now,
      since ifindex alone is not sufficient. This will be
      redone properly for bpf-next tree.

2) Fix test_verifier to avoid using bpf_probe_write_user()
   helper in test cases, since it's dumping a warning into
   kernel log which may confuse users when only running tests.
   Switch to use bpf_trace_printk() instead, from Yonghong.

3) Several fixes for correcting ARG_CONST_SIZE_OR_ZERO semantics
   before it becomes uabi, from Gianluca. More specifically:

    - Add a type ARG_PTR_TO_MEM_OR_NULL that is used only
      by bpf_csum_diff(), where the argument is either a
      valid pointer or NULL. The subsequent ARG_CONST_SIZE_OR_ZERO
      then enforces a valid pointer in case of non-0 size
      or a valid pointer or NULL in case of size 0. Given
      that, the semantics for ARG_PTR_TO_MEM in combination
      with ARG_CONST_SIZE_OR_ZERO are now such that in case
      of size 0, the pointer must always be valid and cannot
      be NULL. This fix in semantics allows for bpf_probe_read()
      to drop the recently added size == 0 check in the helper
      that would become part of uabi otherwise once released.
      At the same time we can then fix bpf_probe_read_str() and
      bpf_perf_event_output() to use ARG_CONST_SIZE_OR_ZERO
      instead of ARG_CONST_SIZE in order to fix recently
      reported issues by Arnaldo et al, where LLVM optimizes
      two boundary checks into a single one for unknown
      variables where the verifier looses track of the variable
      bounds and thus rejects valid programs otherwise.

4) A fix for the verifier for the case when it detects
   comparison of two constants where the branch is guaranteed
   to not be taken at runtime. Verifier will rightfully prune
   the exploration of such paths, but we still pass the program
   to JITs, where they would complain about using reserved
   fields, etc. Track such dead instructions and sanitize
   them with mov r0,r0. Rejection is not possible since LLVM
   may generate them for valid C code and doesn't do as much
   data flow analysis as verifier. For bpf-next we might
   implement removal of such dead code and adjust branches
   instead. Fix from Alexei.
====================

Signed-off-by: David S. Miller