linux-stable.git/include/linux, branch v3.16.35

tun, bpf: fix suspicious RCU usage in tun_{attach, detach}_filter

2016-04-30T22:06:14+00:00

[ Upstream commit 5a5abb1fa3b05dd6aa821525832644c1e7d2905f ]

Sasha Levin reported a suspicious rcu_dereference_protected() warning
found while fuzzing with trinity that is similar to this one:

  [   52.765684] net/core/filter.c:2262 suspicious rcu_dereference_protected() usage!
  [   52.765688] other info that might help us debug this:
  [   52.765695] rcu_scheduler_active = 1, debug_locks = 1
  [   52.765701] 1 lock held by a.out/1525:
  [   52.765704]  #0:  (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20
  [   52.765721] stack backtrace:
  [   52.765728] CPU: 1 PID: 1525 Comm: a.out Not tainted 4.5.0+ #264
  [...]
  [   52.765768] Call Trace:
  [   52.765775]  [] dump_stack+0x85/0xc8
  [   52.765784]  [] lockdep_rcu_suspicious+0xd5/0x110
  [   52.765792]  [] sk_detach_filter+0x82/0x90
  [   52.765801]  [] tun_detach_filter+0x35/0x90 [tun]
  [   52.765810]  [] __tun_chr_ioctl+0x354/0x1130 [tun]
  [   52.765818]  [] ? selinux_file_ioctl+0x130/0x210
  [   52.765827]  [] tun_chr_ioctl+0x13/0x20 [tun]
  [   52.765834]  [] do_vfs_ioctl+0x96/0x690
  [   52.765843]  [] ? security_file_ioctl+0x43/0x60
  [   52.765850]  [] SyS_ioctl+0x79/0x90
  [   52.765858]  [] do_syscall_64+0x62/0x140
  [   52.765866]  [] entry_SYSCALL64_slow_path+0x25/0x25

Same can be triggered with PROVE_RCU (+ PROVE_RCU_REPEATEDLY) enabled
from tun_attach_filter() when user space calls ioctl(tun_fd, TUN{ATTACH,
DETACH}FILTER, ...) for adding/removing a BPF filter on tap devices.

Since the fix in f91ff5b9ff52 ("net: sk_{detach|attach}_filter() rcu
fixes") sk_attach_filter()/sk_detach_filter() now dereferences the
filter with rcu_dereference_protected(), checking whether socket lock
is held in control path.

Since its introduction in 994051625981 ("tun: socket filter support"),
tap filters are managed under RTNL lock from __tun_chr_ioctl(). Thus the
sock_owned_by_user(sk) doesn't apply in this specific case and therefore
triggers the false positive.

Extend the BPF API with __sk_attach_filter()/__sk_detach_filter() pair
that is used by tap filters and pass in lockdep_rtnl_is_held() for the
rcu_dereference_protected() checks instead.

Reported-by: Sasha Levin 
Signed-off-by: Daniel Borkmann 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.16:
 - Drop changes to sk_attach_bpf(), __sk_attach_prog()
 - Adjust context]
Signed-off-by: Ben Hutchings

net: validate variable length ll headers

2016-04-30T22:06:13+00:00

[ Upstream commit 2793a23aacbd754dbbb5cb75093deb7e4103bace ]

Netdevice parameter hard_header_len is variously interpreted both as
an upper and lower bound on link layer header length. The field is
used as upper bound when reserving room at allocation, as lower bound
when validating user input in PF_PACKET.

Clarify the definition to be maximum header length. For validation
of untrusted headers, add an optional validate member to header_ops.

Allow bypassing of validation by passing CAP_SYS_RAWIO, for instance
for deliberate testing of corrupt input. In this case, pad trailing
bytes, as some device drivers expect completely initialized headers.

See also http://comments.gmane.org/gmane.linux.network/401064

Signed-off-by: Willem de Bruijn 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.16: net_device has inline comments instead of kernel-doc]
Signed-off-by: Ben Hutchings

compiler-gcc: disable -ftracer for __noclone functions

2016-04-30T22:06:08+00:00

commit 95272c29378ee7dc15f43fa2758cb28a5913a06d upstream.

-ftracer can duplicate asm blocks causing compilation to fail in
noclone functions.  For example, KVM declares a global variable
in an asm like

    asm("2: ... \n
         .pushsection data \n
         .global vmx_return \n
         vmx_return: .long 2b");

and -ftracer causes a double declaration.

Cc: Andrew Morton 
Cc: Michal Marek 
Cc: kvm@vger.kernel.org
Reported-by: Linda Walsh 
Signed-off-by: Paolo Bonzini 
[bwh: Backported to 3.16: apply to compiler-gcc{4,5}.h]
Signed-off-by: Ben Hutchings

fs/coredump: prevent fsuid=0 dumps into user-controlled directories

2016-04-30T22:06:04+00:00

commit 378c6520e7d29280f400ef2ceaf155c86f05a71a upstream.

This commit fixes the following security hole affecting systems where
all of the following conditions are fulfilled:

 - The fs.suid_dumpable sysctl is set to 2.
 - The kernel.core_pattern sysctl's value starts with "/". (Systems
   where kernel.core_pattern starts with "|/" are not affected.)
 - Unprivileged user namespace creation is permitted. (This is
   true on Linux >=3.8, but some distributions disallow it by
   default using a distro patch.)

Under these conditions, if a program executes under secure exec rules,
causing it to run with the SUID_DUMP_ROOT flag, then unshares its user
namespace, changes its root directory and crashes, the coredump will be
written using fsuid=0 and a path derived from kernel.core_pattern - but
this path is interpreted relative to the root directory of the process,
allowing the attacker to control where a coredump will be written with
root privileges.

To fix the security issue, always interpret core_pattern for dumps that
are written under SUID_DUMP_ROOT relative to the root directory of init.

Signed-off-by: Jann Horn 
Acked-by: Kees Cook 
Cc: Al Viro 
Cc: "Eric W. Biederman" 
Cc: Andy Lutomirski 
Cc: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

tracing: Fix trace_printk() to print when not using bprintk()

2016-04-30T22:06:03+00:00

commit 3debb0a9ddb16526de8b456491b7db60114f7b5e upstream.

The trace_printk() code will allocate extra buffers if the compile detects
that a trace_printk() is used. To do this, the format of the trace_printk()
is saved to the __trace_printk_fmt section, and if that section is bigger
than zero, the buffers are allocated (along with a message that this has
happened).

If trace_printk() uses a format that is not a constant, and thus something
not guaranteed to be around when the print happens, the compiler optimizes
the fmt out, as it is not used, and the __trace_printk_fmt section is not
filled. This means the kernel will not allocate the special buffers needed
for the trace_printk() and the trace_printk() will not write anything to the
tracing buffer.

Adding a "__used" to the variable in the __trace_printk_fmt section will
keep it around, even though it is set to NULL. This will keep the string
from being printed in the debugfs/tracing/printk_formats section as it is
not needed.

Reported-by: Vlastimil Babka 
Fixes: 07d777fe8c398 "tracing: Add percpu buffers for trace_printk()"
Signed-off-by: Steven Rostedt 
Signed-off-by: Ben Hutchings

tunnels: Don't apply GRO to multiple layers of encapsulation.

2016-04-30T22:06:03+00:00

commit fac8e0f579695a3ecbc4d3cac369139d7f819971 upstream.

When drivers express support for TSO of encapsulated packets, they
only mean that they can do it for one layer of encapsulation.
Supporting additional levels would mean updating, at a minimum,
more IP length fields and they are unaware of this.

No encapsulation device expresses support for handling offloaded
encapsulated packets, so we won't generate these types of frames
in the transmit path. However, GRO doesn't have a check for
multiple levels of encapsulation and will attempt to build them.

UDP tunnel GRO actually does prevent this situation but it only
handles multiple UDP tunnels stacked on top of each other. This
generalizes that solution to prevent any kind of tunnel stacking
that would cause problems.

Fixes: bf5a755f ("net-gre-gro: Add GRE support to the GRO stack")
Signed-off-by: Jesse Gross 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.16:
 - Drop the ipip and sit cases
 - Adjust context]
Signed-off-by: Ben Hutchings

net/mlx5: Make command timeout way shorter

2016-04-30T22:05:52+00:00

commit 6b6c07bdcdc97ccac2596063bfc32a5faddfe884 upstream.

The command timeout is terribly long, whole two hours. Make it 60s so if
things do go wrong, the user gets feedback in relatively short time, so
they can take corrective actions and/or investigate using tools and such.

Fixes: e126ba97dba9 ('mlx5: Add driver for Mellanox Connect-IB adapters')
Signed-off-by: Or Gerlitz 
Signed-off-by: Leon Romanovsky 
Signed-off-by: Saeed Mahameed 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

PCI: Disable IO/MEM decoding for devices with non-compliant BARs

2016-04-30T22:05:50+00:00

commit b84106b4e2290c081cdab521fa832596cdfea246 upstream.

The PCI config header (first 64 bytes of each device's config space) is
defined by the PCI spec so generic software can identify the device and
manage its usage of I/O, memory, and IRQ resources.

Some non-spec-compliant devices put registers other than BARs where the
BARs should be.  When the PCI core sizes these "BARs", the reads and writes
it does may have unwanted side effects, and the "BAR" may appear to
describe non-sensical address space.

Add a flag bit to mark non-compliant devices so we don't touch their BARs.
Turn off IO/MEM decoding to prevent the devices from consuming address
space, since we can't read the BARs to find out what that address space
would be.

Signed-off-by: Bjorn Helgaas 
Tested-by: Andi Kleen 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

mtd: map: fix .set_vpp() documentation

2016-04-30T22:05:47+00:00

commit 95a001f22b1c5717eafd500a43832249ddd93662 upstream.

As of commit 876fe76d793d03077eb61ba3afab4a383f46c554
"mtd: maps: physmap: Add reference counter to set_vpp()"
the comment in the header file is incorrect and misleading.
Fix it up.

Cc: Russell King 
Cc: Paul Parsons 
Fixes: 876fe76d793d ("mtd: maps: physmap: Add reference counter to set_vpp()")
Signed-off-by: Linus Walleij 
Signed-off-by: Brian Norris 
Signed-off-by: Ben Hutchings

tty: Fix GPF in flush_to_ldisc(), part 2

2016-04-30T22:05:45+00:00

commit f33798deecbd59a2955f40ac0ae2bc7dff54c069 upstream.

commit 9ce119f318ba ("tty: Fix GPF in flush_to_ldisc()") fixed a
GPF caused by a line discipline which does not define a receive_buf()
method.

However, the vt driver (and speakup driver also) pushes selection
data directly to the line discipline receive_buf() method via
tty_ldisc_receive_buf(). Fix the same problem in tty_ldisc_receive_buf().

Signed-off-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Ben Hutchings