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Carlos Llamas b2a97babb0 binder: fix alloc->vma_vm_mm null-ptr dereference 
commit 1da52815d5 upstream.

Syzbot reported a couple issues introduced by commit 44e602b4e5
("binder_alloc: add missing mmap_lock calls when using the VMA"), in
which we attempt to acquire the mmap_lock when alloc->vma_vm_mm has not
been initialized yet.

This can happen if a binder_proc receives a transaction without having
previously called mmap() to setup the binder_proc->alloc space in [1].
Also, a similar issue occurs via binder_alloc_print_pages() when we try
to dump the debugfs binder stats file in [2].

Sample of syzbot's crash report:
  ==================================================================
  KASAN: null-ptr-deref in range [0x0000000000000128-0x000000000000012f]
  CPU: 0 PID: 3755 Comm: syz-executor229 Not tainted 6.0.0-rc1-next-20220819-syzkaller #0
  syz-executor229[3755] cmdline: ./syz-executor2294415195
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
  RIP: 0010:__lock_acquire+0xd83/0x56d0 kernel/locking/lockdep.c:4923
  [...]
  Call Trace:
   <TASK>
   lock_acquire kernel/locking/lockdep.c:5666 [inline]
   lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631
   down_read+0x98/0x450 kernel/locking/rwsem.c:1499
   mmap_read_lock include/linux/mmap_lock.h:117 [inline]
   binder_alloc_new_buf_locked drivers/android/binder_alloc.c:405 [inline]
   binder_alloc_new_buf+0xa5/0x19e0 drivers/android/binder_alloc.c:593
   binder_transaction+0x242e/0x9a80 drivers/android/binder.c:3199
   binder_thread_write+0x664/0x3220 drivers/android/binder.c:3986
   binder_ioctl_write_read drivers/android/binder.c:5036 [inline]
   binder_ioctl+0x3470/0x6d00 drivers/android/binder.c:5323
   vfs_ioctl fs/ioctl.c:51 [inline]
   __do_sys_ioctl fs/ioctl.c:870 [inline]
   __se_sys_ioctl fs/ioctl.c:856 [inline]
   __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
   do_syscall_x64 arch/x86/entry/common.c:50 [inline]
   do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
   entry_SYSCALL_64_after_hwframe+0x63/0xcd
   [...]
  ==================================================================

Fix these issues by setting up alloc->vma_vm_mm pointer during open()
and caching directly from current->mm. This guarantees we have a valid
reference to take the mmap_lock during scenarios described above.

[1] https://syzkaller.appspot.com/bug?extid=f7dc54e5be28950ac459
[2] https://syzkaller.appspot.com/bug?extid=a75ebe0452711c9e56d9

Fixes: 44e602b4e5 ("binder_alloc: add missing mmap_lock calls when using the VMA")
Cc: <stable@vger.kernel.org> # v5.15+
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: syzbot+f7dc54e5be28950ac459@syzkaller.appspotmail.com
Reported-by: syzbot+a75ebe0452711c9e56d9@syzkaller.appspotmail.com
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Acked-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20220829201254.1814484-2-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2022-09-08 11:24:02 +02:00
arch powerpc/rtas: Fix RTAS MSR[HV] handling for Cell 2022-09-08 11:24:01 +02:00
block blk-mq: fix io hung due to missing commit_rqs 2022-08-31 17:18:19 +02:00
certs certs: make system keyring depend on x509 parser 2022-07-24 12:53:55 -07:00
crypto KEYS: asymmetric: enforce SM2 signature use pkey algo 2022-08-17 15:16:17 +02:00
Documentation rtla: Fix tracer name 2022-09-05 10:31:31 +02:00
drivers binder: fix alloc->vma_vm_mm null-ptr dereference 2022-09-08 11:24:02 +02:00
fs cachefiles: make on-demand request distribution fairer 2022-09-08 11:24:00 +02:00
include bpf: Allow helpers to accept pointers with a fixed size 2022-09-08 11:23:58 +02:00
init arm64: fix rodata=full 2022-08-31 17:18:19 +02:00
io_uring io_uring: fix issue with io_write() not always undoing sb_start_write() 2022-08-31 17:18:17 +02:00
ipc ipc: Free mq_sysctls if ipc namespace creation failed 2022-06-22 17:47:41 -05:00
kernel bpf: Do mark_chain_precision for ARG_CONST_ALLOC_SIZE_OR_ZERO 2022-09-08 11:23:58 +02:00
lib crypto: lib - remove unneeded selection of XOR_BLOCKS 2022-09-05 10:31:26 +02:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm/slab_common: Deleting kobject in kmem_cache_destroy() without holding slab_mutex/cpu_hotplug_lock 2022-09-08 11:24:00 +02:00
net net/smc: Remove redundant refcount increase 2022-09-08 11:24:00 +02:00
samples sample: bpf: xdp_router_ipv4: Allow the kernel to send arp requests 2022-08-17 15:14:25 +02:00
scripts kbuild: dummy-tools: avoid tmpdir leak in dummy gcc 2022-08-29 11:07:58 +02:00
security landlock: Fix file reparenting without explicit LANDLOCK_ACCESS_FS_REFER 2022-09-08 11:24:02 +02:00
sound ALSA: hda: intel-nhlt: Correct the handling of fmt_config flexible array 2022-09-08 11:23:58 +02:00
tools landlock: Fix file reparenting without explicit LANDLOCK_ACCESS_FS_REFER 2022-09-08 11:24:02 +02:00
usr Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
virt KVM: Unconditionally get a ref to /dev/kvm module when creating a VM 2022-08-25 11:45:05 +02:00
.clang-format clang-format: Fix space after for_each macros 2022-05-20 19:27:16 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore kbuild: split the second line of *.mod into *.usyms 2022-05-08 03:16:59 +09:00
.mailmap ARM: SoC fixes for 5.19, part 4 2022-07-27 09:43:07 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: mark ARM/PALM TREO SUPPORT orphan 2022-07-07 15:17:00 +02:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS io_uring: move to separate directory 2022-08-17 15:14:20 +02:00
Makefile Linux 5.19.7 2022-09-05 10:31:36 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -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.

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.