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Paolo Abeni dc24f8b4ec mptcp: add dummy icsk_sync_mss()
syzbot noted that the master MPTCP socket lacks the icsk_sync_mss
callback, and was able to trigger a null pointer dereference:

BUG: kernel NULL pointer dereference, address: 0000000000000000
PGD 8e171067 P4D 8e171067 PUD 93fa2067 PMD 0
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 8984 Comm: syz-executor066 Not tainted 5.6.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffffc900020b7b80 EFLAGS: 00010246
RAX: 1ffff110124ba600 RBX: 0000000000000000 RCX: ffff88809fefa600
RDX: ffff8880994cdb18 RSI: 0000000000000000 RDI: ffff8880925d3140
RBP: ffffc900020b7bd8 R08: ffffffff870225be R09: fffffbfff140652a
R10: fffffbfff140652a R11: 0000000000000000 R12: ffff8880925d35d0
R13: ffff8880925d3140 R14: dffffc0000000000 R15: 1ffff110124ba6ba
FS:  0000000001a0b880(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000000a6d6f000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 cipso_v4_sock_setattr+0x34b/0x470 net/ipv4/cipso_ipv4.c:1888
 netlbl_sock_setattr+0x2a7/0x310 net/netlabel/netlabel_kapi.c:989
 smack_netlabel security/smack/smack_lsm.c:2425 [inline]
 smack_inode_setsecurity+0x3da/0x4a0 security/smack/smack_lsm.c:2716
 security_inode_setsecurity+0xb2/0x140 security/security.c:1364
 __vfs_setxattr_noperm+0x16f/0x3e0 fs/xattr.c:197
 vfs_setxattr fs/xattr.c:224 [inline]
 setxattr+0x335/0x430 fs/xattr.c:451
 __do_sys_fsetxattr fs/xattr.c:506 [inline]
 __se_sys_fsetxattr+0x130/0x1b0 fs/xattr.c:495
 __x64_sys_fsetxattr+0xbf/0xd0 fs/xattr.c:495
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440199
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffcadc19e48 EFLAGS: 00000246 ORIG_RAX: 00000000000000be
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440199
RDX: 0000000020000200 RSI: 00000000200001c0 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000000000003 R09: 00000000004002c8
R10: 0000000000000009 R11: 0000000000000246 R12: 0000000000401a20
R13: 0000000000401ab0 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
CR2: 0000000000000000

Address the issue adding a dummy icsk_sync_mss callback.
To properly sync the subflows mss and options list we need some
additional infrastructure, which will land to net-next.

Reported-by: syzbot+f4dfece964792d80b139@syzkaller.appspotmail.com
Fixes: 2303f994b3 ("mptcp: Associate MPTCP context with TCP socket")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-26 20:49:50 -08:00
arch Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2020-02-20 15:15:16 -08:00
block block-5.6-2020-02-05 2020-02-06 06:15:23 +00:00
certs certs: Add wrapper function to check blacklisted binary hash 2019-11-12 12:25:50 +11:00
crypto Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2020-02-20 15:15:16 -08:00
Documentation docs: networking: phy: Rephrase paragraph for clarity 2020-02-23 20:42:47 -08:00
drivers net: phy: corrected the return value for genphy_check_and_restart_aneg and genphy_c45_check_and_restart_aneg 2020-02-26 20:41:42 -08:00
fs pipe: make sure to wake up everybody when the last reader/writer closes 2020-02-18 14:34:36 -08:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf 2020-02-26 16:30:17 -08:00
init Various fixes: 2020-02-11 16:39:18 -08:00
ipc Revert "ipc,sem: remove uneeded sem_undo_list lock usage in exit_sem()" 2020-02-21 11:22:15 -08:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-02-21 11:59:51 -08:00
lib lib/stackdepot.c: fix global out-of-bounds in stack_slabs 2020-02-21 11:22:15 -08:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm/sparsemem: pfn_to_page is not valid yet on SPARSEMEM 2020-02-21 11:22:15 -08:00
net mptcp: add dummy icsk_sync_mss() 2020-02-26 20:49:50 -08:00
samples Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
scripts scripts/get_maintainer.pl: deprioritize old Fixes: addresses 2020-02-21 11:22:15 -08:00
security Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2020-02-20 15:15:16 -08:00
sound ASoC: Fixes for v5.6 2020-02-18 13:33:39 +01:00
tools selftests: nft_concat_range: Add test for reported add/flush/add issue 2020-02-26 14:33:09 +01:00
usr Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
virt KVM: Disable preemption in kvm_get_running_vcpu() 2020-02-12 12:19:35 +01:00
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.mailmap A handful of small documentation fixes that wandered in. 2020-02-07 13:03:10 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS open: introduce openat2(2) syscall 2020-01-18 09:19:18 -05:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Char/Misc fixes for 5.6-rc3 2020-02-21 12:57:05 -08:00
Makefile Linux 5.6-rc2 2020-02-16 13:16:59 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.