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commit a880b28a71e39013e357fd3adccd1d8a31bc69a8 upstream.
wake_up_poll() uses nr_exclusive=1, so it's not guaranteed to wake up
all exclusive waiters. Yet, POLLFREE *must* wake up all waiters. epoll
and aio poll are fortunately not affected by this, but it's very
fragile. Thus, the new function wake_up_pollfree() has been introduced.
Convert binder to use wake_up_pollfree().
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Fixes: f5cb779ba163 ("ANDROID: binder: remove waitqueue when thread exits.")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20211209010455.42744-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c21a80ca0684ec2910344d72556c816cb8940c01 upstream.
This is a partial revert of commit
29bc22ac5e5b ("binder: use euid from cred instead of using task").
Setting sender_euid using proc->cred caused some Android system test
regressions that need further investigation. It is a partial
reversion because subsequent patches rely on proc->cred.
Fixes: 29bc22ac5e5b ("binder: use euid from cred instead of using task")
Cc: stable@vger.kernel.org # 4.4+
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Change-Id: I9b1769a3510fed250bb21859ef8beebabe034c66
Link: https://lore.kernel.org/r/20211112180720.2858135-1-tkjos@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 52f88693378a58094c538662ba652aff0253c4fe upstream.
Since binder was integrated with selinux, it has passed
'struct task_struct' associated with the binder_proc
to represent the source and target of transactions.
The conversion of task to SID was then done in the hook
implementations. It turns out that there are race conditions
which can result in an incorrect security context being used.
Fix by using the 'struct cred' saved during binder_open and pass
it to the selinux subsystem.
Cc: stable@vger.kernel.org # 5.14 (need backport for earlier stables)
Fixes: 79af73079d75 ("Add security hooks to binder and implement the hooks for SELinux.")
Suggested-by: Jann Horn <jannh@google.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 29bc22ac5e5bc63275e850f0c8fc549e3d0e306b upstream.
Save the 'struct cred' associated with a binder process
at initial open to avoid potential race conditions
when converting to an euid.
Set a transaction's sender_euid from the 'struct cred'
saved at binder_open() instead of looking up the euid
from the binder proc's 'struct task'. This ensures
the euid is associated with the security context that
of the task that opened binder.
Cc: stable@vger.kernel.org # 4.4+
Fixes: 457b9a6f09f0 ("Staging: android: add binder driver")
Signed-off-by: Todd Kjos <tkjos@google.com>
Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Suggested-by: Jann Horn <jannh@google.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4b836a1426cb0f1ef2a6e211d7e553221594f8fc upstream.
Binder is designed such that a binder_proc never has references to
itself. If this rule is violated, memory corruption can occur when a
process sends a transaction to itself; see e.g.
<https://syzkaller.appspot.com/bug?extid=09e05aba06723a94d43d>.
There is a remaining edgecase through which such a transaction-to-self
can still occur from the context of a task with BINDER_SET_CONTEXT_MGR
access:
- task A opens /dev/binder twice, creating binder_proc instances P1
and P2
- P1 becomes context manager
- P2 calls ACQUIRE on the magic handle 0, allocating index 0 in its
handle table
- P1 dies (by closing the /dev/binder fd and waiting a bit)
- P2 becomes context manager
- P2 calls ACQUIRE on the magic handle 0, allocating index 1 in its
handle table
[this triggers a warning: "binder: 1974:1974 tried to acquire
reference to desc 0, got 1 instead"]
- task B opens /dev/binder once, creating binder_proc instance P3
- P3 calls P2 (via magic handle 0) with (void*)1 as argument (two-way
transaction)
- P2 receives the handle and uses it to call P3 (two-way transaction)
- P3 calls P2 (via magic handle 0) (two-way transaction)
- P2 calls P2 (via handle 1) (two-way transaction)
And then, if P2 does *NOT* accept the incoming transaction work, but
instead closes the binder fd, we get a crash.
Solve it by preventing the context manager from using ACQUIRE on ref 0.
There shouldn't be any legitimate reason for the context manager to do
that.
Additionally, print a warning if someone manages to find another way to
trigger a transaction-to-self bug in the future.
Cc: stable@vger.kernel.org
Fixes: 457b9a6f09f0 ("Staging: android: add binder driver")
Acked-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Martijn Coenen <maco@android.com>
Link: https://lore.kernel.org/r/20200727120424.1627555-1-jannh@google.com
[manual backport: remove fine-grained locking and error reporting that
don't exist in <=4.9]
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f5cb779ba16334b45ba8946d6bfa6d9834d1527f upstream.
binder_poll() passes the thread->wait waitqueue that
can be slept on for work. When a thread that uses
epoll explicitly exits using BINDER_THREAD_EXIT,
the waitqueue is freed, but it is never removed
from the corresponding epoll data structure. When
the process subsequently exits, the epoll cleanup
code tries to access the waitlist, which results in
a use-after-free.
Prevent this by using POLLFREE when the thread exits.
Signed-off-by: Martijn Coenen <maco@android.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: stable <stable@vger.kernel.org> # 4.14
[backport BINDER_LOOPER_STATE_POLL logic as well]
Signed-off-by: Mattias Nissler <mnissler@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 04f5866e41fb70690e28397487d8bd8eea7d712a upstream.
The core dumping code has always run without holding the mmap_sem for
writing, despite that is the only way to ensure that the entire vma
layout will not change from under it. Only using some signal
serialization on the processes belonging to the mm is not nearly enough.
This was pointed out earlier. For example in Hugh's post from Jul 2017:
https://lkml.kernel.org/r/alpine.LSU.2.11.1707191716030.2055@eggly.anvils
"Not strictly relevant here, but a related note: I was very surprised
to discover, only quite recently, how handle_mm_fault() may be called
without down_read(mmap_sem) - when core dumping. That seems a
misguided optimization to me, which would also be nice to correct"
In particular because the growsdown and growsup can move the
vm_start/vm_end the various loops the core dump does around the vma will
not be consistent if page faults can happen concurrently.
Pretty much all users calling mmget_not_zero()/get_task_mm() and then
taking the mmap_sem had the potential to introduce unexpected side
effects in the core dumping code.
Adding mmap_sem for writing around the ->core_dump invocation is a
viable long term fix, but it requires removing all copy user and page
faults and to replace them with get_dump_page() for all binary formats
which is not suitable as a short term fix.
For the time being this solution manually covers the places that can
confuse the core dump either by altering the vma layout or the vma flags
while it runs. Once ->core_dump runs under mmap_sem for writing the
function mmget_still_valid() can be dropped.
Allowing mmap_sem protected sections to run in parallel with the
coredump provides some minor parallelism advantage to the swapoff code
(which seems to be safe enough by never mangling any vma field and can
keep doing swapins in parallel to the core dumping) and to some other
corner case.
In order to facilitate the backporting I added "Fixes: 86039bd3b4e6"
however the side effect of this same race condition in /proc/pid/mem
should be reproducible since before 2.6.12-rc2 so I couldn't add any
other "Fixes:" because there's no hash beyond the git genesis commit.
Because find_extend_vma() is the only location outside of the process
context that could modify the "mm" structures under mmap_sem for
reading, by adding the mmget_still_valid() check to it, all other cases
that take the mmap_sem for reading don't need the new check after
mmget_not_zero()/get_task_mm(). The expand_stack() in page fault
context also doesn't need the new check, because all tasks under core
dumping are frozen.
Link: http://lkml.kernel.org/r/20190325224949.11068-1-aarcange@redhat.com
Fixes: 86039bd3b4e6 ("userfaultfd: add new syscall to provide memory externalization")
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Jann Horn <jannh@google.com>
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Jann Horn <jannh@google.com>
Acked-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[akaher@vmware.com: stable 4.9 backport
- handle binder_update_page_range - mhocko@suse.com]
Signed-off-by: Ajay Kaher <akaher@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8ca86f1639ec5890d400fff9211aca22d0a392eb upstream.
The format specifier "%p" can leak kernel addresses. Use
"%pK" instead. There were 4 remaining cases in binder.c.
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 4.9: adjust context]
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This was done as part of upstream commits fdfb4a99b6ab "8inder:
separate binder allocator structure from binder proc", 19c987241ca1
"binder: separate out binder_alloc functions", and 7a4408c6bd3e
"binder: make sure accesses to proc/thread are safe". However, those
commits made lots of other changes that are not suitable for stable.
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7f3dc0088b98533f17128058fac73cd8b2752ef1 upstream.
proc->files cleanup is initiated by binder_vma_close. Therefore
a reference on the binder_proc is not enough to prevent the
files_struct from being released while the binder_proc still has
a reference. This can lead to an attempt to dereference the
stale pointer obtained from proc->files prior to proc->files
cleanup. This has been seen once in task_get_unused_fd_flags()
when __alloc_fd() is called with a stale "files".
The fix is to protect proc->files with a mutex to prevent cleanup
while in use.
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When commit 4be5a2810489 ("binder: check for binder_thread allocation
failure in binder_poll()") was applied to 4.4-stable and 4.9-stable it
was forgotten to release the global binder lock in the new error path.
The global binder lock wasn't removed until v4.14, by commit
a60b890f607d ("binder: remove global binder lock").
Fix the new error path to release the lock.
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f88982679f54f75daa5b8eff3da72508f1e7422f upstream.
If the kzalloc() in binder_get_thread() fails, binder_poll()
dereferences the resulting NULL pointer.
Fix it by returning POLLERR if the memory allocation failed.
This bug was found by syzkaller using fault injection.
Reported-by: syzbot <syzkaller@googlegroups.com>
Fixes: 457b9a6f09f0 ("Staging: android: add binder driver")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b2a6d1b999a4c13e5997bb864694e77172d45250 upstream.
Commit c4ea41ba195d ("binder: use group leader instead of open thread")'
was incomplete and didn't update a check in binder_mmap(), causing all
mmap() calls into the binder driver to fail.
Signed-off-by: Martijn Coenen <maco@android.com>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 00b40d613352c623aaae88a44e5ded7c912909d7 upstream.
Use wake_up_interruptible_sync() to hint to the scheduler binder
transactions are synchronous wakeups. Disable preemption while waking
to avoid ping-ponging on the binder lock.
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Omprakash Dhyade <odhyade@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c4ea41ba195d01c9af66fb28711a16cc97caa9c5 upstream.
The binder allocator assumes that the thread that
called binder_open will never die for the lifetime of
that proc. That thread is normally the group_leader,
however it may not be. Use the group_leader instead
of current.
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a2b18708ee14baec4ef9c0fba96070bba14d0081 upstream.
This reverts commit a906d6931f3ccaf7de805643190765ddd7378e27.
The patch introduced a race in the binder driver. An attempt to fix the
race was submitted in "[PATCH v2] android: binder: fix dangling pointer
comparison", however the conclusion in the discussion for that patch
was that the original patch should be reverted.
The reversion is being done as part of the fine-grained locking
patchset since the patch would need to be refactored when
proc->vmm_vm_mm is removed from struct binder_proc and added
in the binder allocator.
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Prevent using a binder_ref with only weak references where a strong
reference is required.
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Martijn Coenen <maco@android.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The workqueue is being used to run deferred work for the android binder.
The "binder_deferred_workqueue" queues only a single work item and hence
does not require ordering. Also, this workqueue is not being used on a
memory recliam path. Hence, the singlethreaded workqueue has been
replaced with the use of system_wq.
System workqueues have been able to handle high level of concurrency
for a long time now and hence it's not required to have a singlethreaded
workqueue just to gain concurrency. Unlike a dedicated per-cpu workqueue
created with create_singlethread_workqueue(), system_wq allows multiple
work items to overlap executions even on the same CPU; however, a
per-cpu workqueue doesn't have any CPU locality or global ordering
guarantee unless the target CPU is explicitly specified and thus the
increase of local concurrency shouldn't make any difference.
Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This resolves the merge issues and confusions people were having with
the goldfish drivers due to changes for them showing up in two different
trees.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There's one point was missed in the patch commit da49889deb34 ("staging:
binder: Support concurrent 32 bit and 64 bit processes."). When configure
BINDER_IPC_32BIT, the size of binder_uintptr_t was 32bits, but size of
void * is 64bit on 64bit system. Correct it here.
Signed-off-by: Lisa Du <cldu@marvell.com>
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Fixes: da49889deb34 ("staging: binder: Support concurrent 32 bit and 64 bit processes.")
Cc: <stable@vger.kernel.org>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If a /d/binder/proc/[pid] entry is kept open after linux has
torn down the associated process, binder_proc_show can deference
an invalid binder_proc that has been stashed in the debugfs
inode. Validate that the binder_proc ptr passed into binder_proc_show
has not been freed by looking for it within the global process list
whilst the global lock is held. If the ptr is not valid, print nothing.
Cc: Colin Cross <ccross@android.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Dmitry Shmidt <dimitrysh@google.com>
Cc: Rom Lemarchand <romlem@google.com>
Cc: Serban Constantinescu <serban.constantinescu@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>
[jstultz: Minor commit message tweaks]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Sanity check at binder ioctl function,
Only allow the shared mm_struct to use the same binder-object
to do binder operate.
And add proc->vma_vm_mm = current->mm at the open function.
The libbinder do ioctl before mmap called.
V2: Fix compile error for error commit
V3: Change the condition to proc->vma_vm_mm
Signed-off-by: Chen Feng <puck.chen@hisilicon.com>
Signed-off-by: Wei Dong <weidong2@hisilicon.com>
Signed-off-by: Junmin Zhao <zhaojunmin@huawei.com>
Reviewed-by: Zhuangluan Su <suzhuangluan@hisilicon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
With two exceptions (drm/qxl and drm/radeon) all vm_operations_struct
structs should be constant.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
binder_update_page_range() initializes only addr and size
fields in 'struct vm_struct tmp_area;' and passes it to
map_vm_area().
Before 71394fe50146 ("mm: vmalloc: add flag preventing guard hole allocation")
this was because map_vm_area() didn't use any other fields
in vm_struct except addr and size.
Now get_vm_area_size() (used in map_vm_area()) reads vm_struct's
flags to determine whether vm area has guard hole or not.
binder_update_page_range() don't initialize flags field, so
this causes following binder mmap failures:
-----------[ cut here ]------------
WARNING: CPU: 0 PID: 1971 at mm/vmalloc.c:130
vmap_page_range_noflush+0x119/0x144()
CPU: 0 PID: 1971 Comm: healthd Not tainted 4.0.0-rc1-00399-g7da3fdc-dirty #157
Hardware name: ARM-Versatile Express
[<c001246d>] (unwind_backtrace) from [<c000f7f9>] (show_stack+0x11/0x14)
[<c000f7f9>] (show_stack) from [<c049a221>] (dump_stack+0x59/0x7c)
[<c049a221>] (dump_stack) from [<c001cf21>] (warn_slowpath_common+0x55/0x84)
[<c001cf21>] (warn_slowpath_common) from [<c001cfe3>]
(warn_slowpath_null+0x17/0x1c)
[<c001cfe3>] (warn_slowpath_null) from [<c00c66c5>]
(vmap_page_range_noflush+0x119/0x144)
[<c00c66c5>] (vmap_page_range_noflush) from [<c00c716b>] (map_vm_area+0x27/0x48)
[<c00c716b>] (map_vm_area) from [<c038ddaf>]
(binder_update_page_range+0x12f/0x27c)
[<c038ddaf>] (binder_update_page_range) from [<c038e857>]
(binder_mmap+0xbf/0x1ac)
[<c038e857>] (binder_mmap) from [<c00c2dc7>] (mmap_region+0x2eb/0x4d4)
[<c00c2dc7>] (mmap_region) from [<c00c3197>] (do_mmap_pgoff+0x1e7/0x250)
[<c00c3197>] (do_mmap_pgoff) from [<c00b35b5>] (vm_mmap_pgoff+0x45/0x60)
[<c00b35b5>] (vm_mmap_pgoff) from [<c00c1f39>] (SyS_mmap_pgoff+0x5d/0x80)
[<c00c1f39>] (SyS_mmap_pgoff) from [<c000ce81>] (ret_fast_syscall+0x1/0x5c)
---[ end trace 48c2c4b9a1349e54 ]---
binder: 1982: binder_alloc_buf failed to map page at f0e00000 in kernel
binder: binder_mmap: 1982 b6bde000-b6cdc000 alloc small buf failed -12
Use map_kernel_range_noflush() instead of map_vm_area() as this is better
API for binder's purposes and it allows to get rid of 'vm_struct tmp_area' at all.
Fixes: 71394fe50146 ("mm: vmalloc: add flag preventing guard hole allocation")
Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Reported-by: Amit Pundir <amit.pundir@linaro.org>
Tested-by: Amit Pundir <amit.pundir@linaro.org>
Acked-by: David Rientjes <rientjes@google.com>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add security hooks to the binder and implement the hooks for SELinux.
The security hooks enable security modules such as SELinux to implement
controls over binder IPC. The security hooks include support for
controlling what process can become the binder context manager
(binder_set_context_mgr), controlling the ability of a process
to invoke a binder transaction/IPC to another process (binder_transaction),
controlling the ability of a process to transfer a binder reference to
another process (binder_transfer_binder), and controlling the ability
of a process to transfer an open file to another process (binder_transfer_file).
These hooks have been included in the Android kernel trees since Android 4.3.
(Updated to reflect upstream relocation and changes to the binder driver,
changes to the LSM audit data structures, coding style cleanups, and
to add inline documentation for the hooks).
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Nick Kralevich <nnk@google.com>
Acked-by: Jeffrey Vander Stoep <jeffv@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
binder.h isn't needed to just include a uapi file and set a single
define, so move it into binder.c to save a few lines of code.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Android binder code has been "stable" for many years now. No matter
what comes in the future, we are going to have to support this API, so
might as well move it to the "real" part of the kernel as there's no
real work that needs to be done to the existing code.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
