linux-stable.git/net/socket.c, branch linux-4.9.y

net: Fix a data-race around sysctl_somaxconn.

2022-09-05T08:23:55+00:00

[ Upstream commit 3c9ba81d72047f2e81bb535d42856517b613aba7 ]

While reading sysctl_somaxconn, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

net: Set fput_needed iff FDPUT_FPUT is set

2020-08-21T09:02:04+00:00

[ Upstream commit ce787a5a074a86f76f5d3fd804fa78e01bfb9e89 ]

We should fput() file iff FDPUT_FPUT is set. So we should set fput_needed
accordingly.

Fixes: 00e188ef6a7e ("sockfd_lookup_light(): switch to fdget^W^Waway from fget_light")
Signed-off-by: Miaohe Lin 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

l2tp: device MTU setup, tunnel socket needs a lock

2020-05-27T14:42:00+00:00

commit 57240d007816486131bee88cd474c2a71f0fe224 upstream.

The MTU overhead calculation in L2TP device set-up
merged via commit b784e7ebfce8cfb16c6f95e14e8532d0768ab7ff
needs to be adjusted to lock the tunnel socket while
referencing the sub-data structures to derive the
socket's IP overhead.

Reported-by: Guillaume Nault 
Tested-by: Guillaume Nault 
Signed-off-by: R. Parameswaran 
Signed-off-by: David S. Miller 
Cc: Giuliano Procida 
Signed-off-by: Greg Kroah-Hartman

New kernel function to get IP overhead on a socket.

2020-05-27T14:41:54+00:00

commit 113c3075931a334f899008f6c753abe70a3a9323 upstream.

A new function, kernel_sock_ip_overhead(), is provided
to calculate the cumulative overhead imposed by the IP
Header and IP options, if any, on a socket's payload.
The new function returns an overhead of zero for sockets
that do not belong to the IPv4 or IPv6 address families.
This is used in the L2TP code path to compute the
total outer IP overhead on the L2TP tunnel socket when
calculating the default MTU for Ethernet pseudowires.

Signed-off-by: R. Parameswaran 
Signed-off-by: David S. Miller 
Signed-off-by: Giuliano Procida 
Signed-off-by: Greg Kroah-Hartman

compat_ioctl: handle SIOCOUTQNSD

2020-01-23T07:19:36+00:00

commit 9d7bf41fafa5b5ddd4c13eb39446b0045f0a8167 upstream.

Unlike the normal SIOCOUTQ, SIOCOUTQNSD was never handled in compat
mode. Add it to the common socket compat handler along with similar
ones.

Fixes: 2f4e1b397097 ("tcp: ioctl type SIOCOUTQNSD returns amount of data not sent")
Cc: Eric Dumazet 
Cc: netdev@vger.kernel.org
Cc: "David S. Miller" 
Signed-off-by: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman

bpf: get rid of pure_initcall dependency to enable jits

2019-08-25T08:51:40+00:00

commit fa9dd599b4dae841924b022768354cfde9affecb upstream.

Having a pure_initcall() callback just to permanently enable BPF
JITs under CONFIG_BPF_JIT_ALWAYS_ON is unnecessary and could leave
a small race window in future where JIT is still disabled on boot.
Since we know about the setting at compilation time anyway, just
initialize it properly there. Also consolidate all the individual
bpf_jit_enable variables into a single one and move them under one
location. Moreover, don't allow for setting unspecified garbage
values on them.

Signed-off-by: Daniel Borkmann 
Acked-by: Alexei Starovoitov 
Signed-off-by: Alexei Starovoitov 
[bwh: Backported to 4.9 as dependency of commit 2e4a30983b0f
 "bpf: restrict access to core bpf sysctls":
 - Drop change in arch/mips/net/ebpf_jit.c
 - Drop change to bpf_jit_kallsyms
 - Adjust filenames, context]
Signed-off-by: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

net: socket: fix a missing-check bug

2018-11-10T15:42:58+00:00

[ Upstream commit b6168562c8ce2bd5a30e213021650422e08764dc ]

In ethtool_ioctl(), the ioctl command 'ethcmd' is checked through a switch
statement to see whether it is necessary to pre-process the ethtool
structure, because, as mentioned in the comment, the structure
ethtool_rxnfc is defined with padding. If yes, a user-space buffer 'rxnfc'
is allocated through compat_alloc_user_space(). One thing to note here is
that, if 'ethcmd' is ETHTOOL_GRXCLSRLALL, the size of the buffer 'rxnfc' is
partially determined by 'rule_cnt', which is actually acquired from the
user-space buffer 'compat_rxnfc', i.e., 'compat_rxnfc->rule_cnt', through
get_user(). After 'rxnfc' is allocated, the data in the original user-space
buffer 'compat_rxnfc' is then copied to 'rxnfc' through copy_in_user(),
including the 'rule_cnt' field. However, after this copy, no check is
re-enforced on 'rxnfc->rule_cnt'. So it is possible that a malicious user
race to change the value in the 'compat_rxnfc->rule_cnt' between these two
copies. Through this way, the attacker can bypass the previous check on
'rule_cnt' and inject malicious data. This can cause undefined behavior of
the kernel and introduce potential security risk.

This patch avoids the above issue via copying the value acquired by
get_user() to 'rxnfc->rule_cn', if 'ethcmd' is ETHTOOL_GRXCLSRLALL.

Signed-off-by: Wenwen Wang 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: socket: fix potential spectre v1 gadget in socketcall

2018-08-06T14:23:04+00:00

commit c8e8cd579bb4265651df8223730105341e61a2d1 upstream.

'call' is a user-controlled value, so sanitize the array index after the
bounds check to avoid speculating past the bounds of the 'nargs' array.

Found with the help of Smatch:

net/socket.c:2508 __do_sys_socketcall() warn: potential spectre issue
'nargs' [r] (local cap)

Cc: Josh Poimboeuf 
Cc: stable@vger.kernel.org
Signed-off-by: Jeremy Cline 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

bpf: introduce BPF_JIT_ALWAYS_ON config

2018-01-31T11:55:56+00:00

[ upstream commit 290af86629b25ffd1ed6232c4e9107da031705cb ]

The BPF interpreter has been used as part of the spectre 2 attack CVE-2017-5715.

A quote from goolge project zero blog:
"At this point, it would normally be necessary to locate gadgets in
the host kernel code that can be used to actually leak data by reading
from an attacker-controlled location, shifting and masking the result
appropriately and then using the result of that as offset to an
attacker-controlled address for a load. But piecing gadgets together
and figuring out which ones work in a speculation context seems annoying.
So instead, we decided to use the eBPF interpreter, which is built into
the host kernel - while there is no legitimate way to invoke it from inside
a VM, the presence of the code in the host kernel's text section is sufficient
to make it usable for the attack, just like with ordinary ROP gadgets."

To make attacker job harder introduce BPF_JIT_ALWAYS_ON config
option that removes interpreter from the kernel in favor of JIT-only mode.
So far eBPF JIT is supported by:
x64, arm64, arm32, sparc64, s390, powerpc64, mips64

The start of JITed program is randomized and code page is marked as read-only.
In addition "constant blinding" can be turned on with net.core.bpf_jit_harden

v2->v3:
- move __bpf_prog_ret0 under ifdef (Daniel)

v1->v2:
- fix init order, test_bpf and cBPF (Daniel's feedback)
- fix offloaded bpf (Jakub's feedback)
- add 'return 0' dummy in case something can invoke prog->bpf_func
- retarget bpf tree. For bpf-next the patch would need one extra hunk.
  It will be sent when the trees are merged back to net-next

Considered doing:
  int bpf_jit_enable __read_mostly = BPF_EBPF_JIT_DEFAULT;
but it seems better to land the patch as-is and in bpf-next remove
bpf_jit_enable global variable from all JITs, consolidate in one place
and remove this jit_init() function.

Signed-off-by: Alexei Starovoitov 
Signed-off-by: Daniel Borkmann 
Signed-off-by: Greg Kroah-Hartman

net: initialize msg.msg_flags in recvfrom

2017-12-20T09:07:18+00:00

[ Upstream commit 9f138fa609c47403374a862a08a41394be53d461 ]

KMSAN reports a use of uninitialized memory in put_cmsg() because
msg.msg_flags in recvfrom haven't been initialized properly.
The flag values don't affect the result on this path, but it's still a
good idea to initialize them explicitly.

Signed-off-by: Alexander Potapenko 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman