binder_mmap() tries to prevent the creation of overly big binder mappings
by silently truncating the size of the VMA to 4MiB. However, this violates
the API contract of mmap(). If userspace attempts to create a large binder
VMA, and later attempts to unmap that VMA, it will call munmap() on a range
beyond the end of the VMA, which may have been allocated to another VMA in
the meantime. This can lead to userspace memory corruption.
The following sequence of calls leads to a segfault without this commit:
int main(void) {
int binder_fd = open("/dev/binder", O_RDWR);
if (binder_fd == -1) err(1, "open binder");
void *binder_mapping = mmap(NULL, 0x800000UL, PROT_READ, MAP_SHARED,
binder_fd, 0);
if (binder_mapping == MAP_FAILED) err(1, "mmap binder");
void *data_mapping = mmap(NULL, 0x400000UL, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
if (data_mapping == MAP_FAILED) err(1, "mmap data");
munmap(binder_mapping, 0x800000UL);
*(char*)data_mapping = 1;
return 0;
}
Cc: stable@vger.kernel.org
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Todd Kjos <tkjos@google.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20191016150119.154756-1-jannh@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently /sys/kernel/debug/binder/proc contains
the debug data for every binder_proc instance.
This patch makes this information also available
in a binderfs instance mounted with a mount option
"stats=global" in addition to debugfs. The patch does
not affect the presence of the file in debugfs.
If a binderfs instance is mounted at path /dev/binderfs,
this file would be present at /dev/binderfs/binder_logs/proc.
This change provides an alternate way to access this file when debugfs
is not mounted.
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Hridya Valsaraju <hridya@google.com>
Link: https://lore.kernel.org/r/20190903161655.107408-5-hridya@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, the binder transaction log files 'transaction_log'
and 'failed_transaction_log' live in debugfs at the following locations:
/sys/kernel/debug/binder/failed_transaction_log
/sys/kernel/debug/binder/transaction_log
This patch makes these files also available in a binderfs instance
mounted with the mount option "stats=global".
It does not affect the presence of these files in debugfs.
If a binderfs instance is mounted at path /dev/binderfs, the location of
these files will be as follows:
/dev/binderfs/binder_logs/failed_transaction_log
/dev/binderfs/binder_logs/transaction_log
This change provides an alternate option to access these files when
debugfs is not mounted.
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Hridya Valsaraju <hridya@google.com>
Link: https://lore.kernel.org/r/20190903161655.107408-4-hridya@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The following binder stat files currently live in debugfs.
/sys/kernel/debug/binder/state
/sys/kernel/debug/binder/stats
/sys/kernel/debug/binder/transactions
This patch makes these files available in a binderfs instance
mounted with the mount option 'stats=global'. For example, if a binderfs
instance is mounted at path /dev/binderfs, the above files will be
available at the following locations:
/dev/binderfs/binder_logs/state
/dev/binderfs/binder_logs/stats
/dev/binderfs/binder_logs/transactions
This provides a way to access them even when debugfs is not mounted.
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Hridya Valsaraju <hridya@google.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20190903161655.107408-3-hridya@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, all binder state and statistics live in debugfs.
We need this information even when debugfs is not mounted.
This patch adds the mount option 'stats' to enable a binderfs
instance to have binder debug information present in the same.
'stats=global' will enable the global binder statistics. In
the future, 'stats=local' will enable binder statistics local
to the binderfs instance. The two modes 'global' and 'local'
will be mutually exclusive. 'stats=global' option is only available
for a binderfs instance mounted in the initial user namespace.
An attempt to use the option to mount a binderfs instance in
another user namespace will return an EPERM error.
Signed-off-by: Hridya Valsaraju <hridya@google.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20190903161655.107408-2-hridya@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The buffer copy functions assumed the caller would ensure
correct alignment and that the memory to be copied was
completely within the binder buffer. There have been
a few cases discovered by syzkallar where a malformed
transaction created by a user could violated the
assumptions and resulted in a BUG_ON.
The fix is to remove the BUG_ON and always return the
error to be handled appropriately by the caller.
Acked-by: Martijn Coenen <maco@android.com>
Reported-by: syzbot+3ae18325f96190606754@syzkaller.appspotmail.com
Fixes: bde4a19fc0 ("binder: use userspace pointer as base of buffer space")
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
syzkallar found a 32-byte memory leak in a rarely executed error
case. The transaction complete work item was not freed if put_user()
failed when writing the BR_TRANSACTION_COMPLETE to the user command
buffer. Fixed by freeing it before put_user() is called.
Reported-by: syzbot+182ce46596c3f2e1eb24@syzkaller.appspotmail.com
Signed-off-by: Todd Kjos <tkjos@google.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There is a race between the binder driver cleaning
up a completed transaction via binder_free_transaction()
and a user calling binder_ioctl(BC_FREE_BUFFER) to
release a buffer. It doesn't matter which is first but
they need to be protected against running concurrently
which can result in a UAF.
Signed-off-by: Todd Kjos <tkjos@google.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Based on 1 normalized pattern(s):
this software is licensed under the terms of the gnu general public
license version 2 as published by the free software foundation and
may be copied distributed and modified under those terms this
program is distributed in the hope that it will be useful but
without any warranty without even the implied warranty of
merchantability or fitness for a particular purpose see the gnu
general public license for more details
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 285 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141900.642774971@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add SPDX license identifiers to all Make/Kconfig files which:
- Have no license information of any form
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull char/misc update part 2 from Greg KH:
"Here is the "real" big set of char/misc driver patches for 5.2-rc1
Loads of different driver subsystem stuff in here, all over the places:
- thunderbolt driver updates
- habanalabs driver updates
- nvmem driver updates
- extcon driver updates
- intel_th driver updates
- mei driver updates
- coresight driver updates
- soundwire driver cleanups and updates
- fastrpc driver updates
- other minor driver updates
- chardev minor fixups
Feels like this tree is getting to be a dumping ground of "small
driver subsystems" these days. Which is fine with me, if it makes
things easier for those subsystem maintainers.
All of these have been in linux-next for a while with no reported
issues"
* tag 'char-misc-5.2-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (255 commits)
intel_th: msu: Add current window tracking
intel_th: msu: Add a sysfs attribute to trigger window switch
intel_th: msu: Correct the block wrap detection
intel_th: Add switch triggering support
intel_th: gth: Factor out trace start/stop
intel_th: msu: Factor out pipeline draining
intel_th: msu: Switch over to scatterlist
intel_th: msu: Replace open-coded list_{first,last,next}_entry variants
intel_th: Only report useful IRQs to subdevices
intel_th: msu: Start handling IRQs
intel_th: pci: Use MSI interrupt signalling
intel_th: Communicate IRQ via resource
intel_th: Add "rtit" source device
intel_th: Skip subdevices if their MMIO is missing
intel_th: Rework resource passing between glue layers and core
intel_th: SPDX-ify the documentation
intel_th: msu: Fix single mode with IOMMU
coresight: funnel: Support static funnel
dt-bindings: arm: coresight: Unify funnel DT binding
coresight: replicator: Add new device id for static replicator
...
When allocating space in the target buffer for the security context,
make sure the extra_buffers_size doesn't overflow. This can only
happen if the given size is invalid, but an overflow can turn it
into a valid size. Fail the transaction if an overflow is detected.
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Restore the behavior of locking mmap_sem for reading in
binder_alloc_free_page(), as was first done in commit 3013bf62b6
("binder: reduce mmap_sem write-side lock"). That change was
inadvertently reverted by commit 5cec2d2e58 ("binder: fix race between
munmap() and direct reclaim").
In addition, change the name of the label for the error path to
accurately reflect that we're taking the lock for reading.
Backporting note: This fix is only needed when *both* of the commits
mentioned above are applied. That's an unlikely situation since they
both landed during the development of v5.1 but only one of them is
targeted for stable.
Fixes: 5cec2d2e58 ("binder: fix race between munmap() and direct reclaim")
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Acked-by: Todd Kjos <tkjos@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
An munmap() on a binder device causes binder_vma_close() to be called
which clears the alloc->vma pointer.
If direct reclaim causes binder_alloc_free_page() to be called, there
is a race where alloc->vma is read into a local vma pointer and then
used later after the mm->mmap_sem is acquired. This can result in
calling zap_page_range() with an invalid vma which manifests as a
use-after-free in zap_page_range().
The fix is to check alloc->vma after acquiring the mmap_sem (which we
were acquiring anyway) and skip zap_page_range() if it has changed
to NULL.
Signed-off-by: Todd Kjos <tkjos@google.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The selinux-testsuite found an issue resulting in a BUG_ON()
where a conditional relied on a size_t going negative when
checking the validity of a buffer offset.
Fixes: 7a67a39320 ("binder: add function to copy binder object from buffer")
Reported-by: Paul Moore <paul@paul-moore.com>
Tested-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
binder has used write-side mmap_sem semaphore to release memory
mapped at address space of the process. However, right lock to
release pages is down_read, not down_write because page table lock
already protects the race for parallel freeing.
Please do not use mmap_sem write-side lock which is well known
contented lock.
Cc: Todd Kjos <tkjos@google.com>
Cc: Martijn Coenen <maco@android.com>
Cc: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes sparse issues reported by the kbuild test robot running
on https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
char-misc-testing: bde4a19fc0 ("binder: use userspace pointer as base
of buffer space")
Error output (drivers/android/binder_alloc_selftest.c):
sparse: warning: incorrect type in assignment (different address spaces)
sparse: expected void *page_addr
sparse: got void [noderef] <asn:1> *user_data
sparse: error: subtraction of different types can't work
Fixed by adding necessary "__user" tags.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
