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Daniel Borkmann f6fadff33e tls: fix NULL pointer dereference on poll
While hacking on kTLS, I ran into the following panic from an
unprivileged netserver / netperf TCP session:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
  PGD 800000037f378067 P4D 800000037f378067 PUD 3c0e61067 PMD 0
  Oops: 0010 [#1] SMP KASAN PTI
  CPU: 1 PID: 2289 Comm: netserver Not tainted 4.17.0+ #139
  Hardware name: LENOVO 20FBCTO1WW/20FBCTO1WW, BIOS N1FET47W (1.21 ) 11/28/2016
  RIP: 0010:          (null)
  Code: Bad RIP value.
  RSP: 0018:ffff88036abcf740 EFLAGS: 00010246
  RAX: dffffc0000000000 RBX: ffff88036f5f6800 RCX: 1ffff1006debed26
  RDX: ffff88036abcf920 RSI: ffff8803cb1a4f00 RDI: ffff8803c258c280
  RBP: ffff8803c258c280 R08: ffff8803c258c280 R09: ffffed006f559d48
  R10: ffff88037aacea43 R11: ffffed006f559d49 R12: ffff8803c258c280
  R13: ffff8803cb1a4f20 R14: 00000000000000db R15: ffffffffc168a350
  FS:  00007f7e631f4700(0000) GS:ffff8803d1c80000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: ffffffffffffffd6 CR3: 00000003ccf64005 CR4: 00000000003606e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   ? tls_sw_poll+0xa4/0x160 [tls]
   ? sock_poll+0x20a/0x680
   ? do_select+0x77b/0x11a0
   ? poll_schedule_timeout.constprop.12+0x130/0x130
   ? pick_link+0xb00/0xb00
   ? read_word_at_a_time+0x13/0x20
   ? vfs_poll+0x270/0x270
   ? deref_stack_reg+0xad/0xe0
   ? __read_once_size_nocheck.constprop.6+0x10/0x10
  [...]

Debugging further, it turns out that calling into ctx->sk_poll() is
invalid since sk_poll itself is NULL which was saved from the original
TCP socket in order for tls_sw_poll() to invoke it.

Looks like the recent conversion from poll to poll_mask callback started
in 1525242310 ("net: add support for ->poll_mask in proto_ops") missed
to eventually convert kTLS, too: TCP's ->poll was converted over to the
->poll_mask in commit 2c7d3daceb ("net/tcp: convert to ->poll_mask")
and therefore kTLS wrongly saved the ->poll old one which is now NULL.

Convert kTLS over to use ->poll_mask instead. Also instead of POLLIN |
POLLRDNORM use the proper EPOLLIN | EPOLLRDNORM bits as the case in
tcp_poll_mask() as well that is mangled here.

Fixes: 2c7d3daceb ("net/tcp: convert to ->poll_mask")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Watson <davejwatson@fb.com>
Tested-by: Dave Watson <davejwatson@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-11 16:29:54 -07:00
Documentation RTC for 4.18 2018-06-10 16:13:24 -07:00
LICENSES LICENSES: Add Linux-OpenIB license text 2018-04-27 16:41:53 -06:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-06-10 19:25:23 -07:00
block for-linus-20180610 2018-06-10 10:50:41 -07:00
certs certs/blacklist_nohashes.c: fix const confusion in certs blacklist 2018-02-21 15:35:43 -08:00
crypto - Introduce arithmetic overflow test helper functions (Rasmus) 2018-06-06 17:27:14 -07:00
drivers Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-06-10 19:25:23 -07:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs This pull request contains updates for both UBI and UBIFS: 2018-06-10 15:52:09 -07:00
include tls: fix NULL pointer dereference on poll 2018-06-11 16:29:54 -07:00
init Merge branch 'core-rseq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-10 10:17:09 -07:00
ipc Merge branch 'timers-2038-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-04 21:02:18 -07:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-06-10 19:25:23 -07:00
lib libnvdimm for 4.18 2018-06-08 17:21:52 -07:00
mm libnvdimm for 4.18 2018-06-08 17:21:52 -07:00
net tls: fix NULL pointer dereference on poll 2018-06-11 16:29:54 -07:00
samples Mostly small fixes and cleanups, plus a non-trivial fix for charlcd 2018-06-07 14:01:16 -07:00
scripts Staging/IIO patches for 4.18-rc1 2018-06-09 10:32:39 -07:00
security Merge branch 'next-smack' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2018-06-07 15:57:04 -07:00
sound media updates for v4.18-rc1 2018-06-07 12:34:37 -07:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-06-10 19:25:23 -07:00
usr kbuild: rename built-in.o to built-in.a 2018-03-26 02:01:19 +09:00
virt arm64 updates for 4.18: 2018-06-08 11:10:58 -07:00
.clang-format clang-format: add configuration file 2018-04-11 10:28:35 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap Merge branch 'asoc-4.17' into asoc-4.18 for compress dependencies 2018-04-26 12:24:28 +01:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS/CREDITS: Drop METAG ARCHITECTURE 2018-03-05 16:34:24 +00:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: add basic helper macros to scripts/Kconfig.include 2018-05-29 03:31:19 +09:00
MAINTAINERS SCSI misc on 20180610 2018-06-10 13:01:12 -07:00
Makefile Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-06-06 18:39:49 -07:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

README

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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.