When handling BINDER_TYPE_FDA object we are pushing a parent fixup
with a certain skip_size but no scatter-gather copy object, since
the copy is handled standalone.
If BINDER_TYPE_FDA is the last children the scatter-gather copy
loop will never stop to skip it, thus we are left with an item in
the parent fixup list. This will trigger the BUG_ON().
This is reproducible in android when playing a video.
We receive a transaction that looks like this:
obj[0] BINDER_TYPE_PTR, parent
obj[1] BINDER_TYPE_PTR, child
obj[2] BINDER_TYPE_PTR, child
obj[3] BINDER_TYPE_FDA, child
Fixes: 09184ae9b5 ("binder: defer copies of pre-patched txn data")
Acked-by: Todd Kjos <tkjos@google.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Alessandro Astone <ales.astone@gmail.com>
Link: https://lore.kernel.org/r/20220415120015.52684-2-ales.astone@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
binder.c uses <asm/cacheflush.h> instead of <linux/cacheflush.h>.
Hence change cacheflush header file to proper one.
This change also avoid warning from checkpatch that shown below:
WARNING: Use #include <linux/cacheflush.h> instead of <asm/cacheflush.h>
Signed-off-by: Ajith P V <ajithpv.linux@gmail.com>
Link: https://lore.kernel.org/r/20211215132018.31522-1-ajithpv.linux@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We need the fixes in here as well, and also resolve some merge conflicts
in:
drivers/misc/eeprom/at25.c
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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: f5cb779ba1 ("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>
binder_uintptr_t is not the same as uintptr_t, so converting it into a
pointer requires a second cast:
drivers/android/binder.c: In function 'binder_translate_fd_array':
drivers/android/binder.c:2511:28: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
2511 | sender_ufda_base = (void __user *)sender_uparent->buffer + fda->parent_offset;
| ^
Fixes: 656e01f3ab ("binder: read pre-translated fds from sender buffer")
Acked-by: Todd Kjos <tkjos@google.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20211207122448.1185769-1-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
BINDER_TYPE_PTR objects point to memory areas in the
source process to be copied into the target buffer
as part of a transaction. This implements a scatter-
gather model where non-contiguous memory in a source
process is "gathered" into a contiguous region in
the target buffer.
The data can include pointers that must be fixed up
to correctly point to the copied data. To avoid making
source process pointers visible to the target process,
this patch defers the copy until the fixups are known
and then copies and fixeups are done together.
There is a special case of BINDER_TYPE_FDA which applies
the fixup later in the target process context. In this
case the user data is skipped (so no untranslated fds
become visible to the target).
Reviewed-by: Martijn Coenen <maco@android.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20211130185152.437403-5-tkjos@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch is to prepare for an up coming patch where we read
pre-translated fds from the sender buffer and translate them before
copying them to the target. It does not change run time.
The patch adds two new parameters to binder_translate_fd_array() to
hold the sender buffer and sender buffer parent. These parameters let
us call copy_from_user() directly from the sender instead of using
binder_alloc_copy_from_buffer() to copy from the target. Also the patch
adds some new alignment checks. Previously the alignment checks would
have been done in a different place, but this lets us print more
useful error messages.
Reviewed-by: Martijn Coenen <maco@android.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20211130185152.437403-4-tkjos@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Transactions are copied from the sender to the target
first and objects like BINDER_TYPE_PTR and BINDER_TYPE_FDA
are then fixed up. This means there is a short period where
the sender's version of these objects are visible to the
target prior to the fixups.
Instead of copying all of the data first, copy data only
after any needed fixups have been applied.
Fixes: 457b9a6f09 ("Staging: android: add binder driver")
Reviewed-by: Martijn Coenen <maco@android.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20211130185152.437403-3-tkjos@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If a memory copy function fails to copy the whole buffer,
a positive integar with the remaining bytes is returned.
In binder_translate_fd_array() this can result in an fd being
skipped due to the failed copy, but the loop continues
processing fds since the early return condition expects a
negative integer on error.
Fix by returning "ret > 0 ? -EINVAL : ret" to handle this case.
Fixes: bb4a2e48d5 ("binder: return errors from buffer copy functions")
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20211130185152.437403-2-tkjos@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
binder.c file comment produce warning with checkpatch as below:
WARNING: Possible repeated word: 'for'
Remove the repeated word from the comment avoid this warning.
Signed-off-by: Ajith P V <ajithpv.linux@gmail.com>
Link: https://lore.kernel.org/r/20211125122218.6767-1-ajithpv.linux@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is a partial revert of commit
29bc22ac5e ("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: 29bc22ac5e ("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>
Here is the big set of char and misc and other tiny driver subsystem
updates for 5.16-rc1.
Loads of things in here, all of which have been in linux-next for a
while with no reported problems (except for one called out below.)
Included are:
- habanana labs driver updates, including dma_buf usage,
reviewed and acked by the dma_buf maintainers
- iio driver update (going through this tree not staging as they
really do not belong going through that tree anymore)
- counter driver updates
- hwmon driver updates that the counter drivers needed, acked by
the hwmon maintainer
- xillybus driver updates
- binder driver updates
- extcon driver updates
- dma_buf module namespaces added (will cause a build error in
arm64 for allmodconfig, but that change is on its way through
the drm tree)
- lkdtm driver updates
- pvpanic driver updates
- phy driver updates
- virt acrn and nitr_enclaves driver updates
- smaller char and misc driver updates
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'char-misc-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char/misc driver updates from Greg KH:
"Here is the big set of char and misc and other tiny driver subsystem
updates for 5.16-rc1.
Loads of things in here, all of which have been in linux-next for a
while with no reported problems (except for one called out below.)
Included are:
- habanana labs driver updates, including dma_buf usage, reviewed and
acked by the dma_buf maintainers
- iio driver update (going through this tree not staging as they
really do not belong going through that tree anymore)
- counter driver updates
- hwmon driver updates that the counter drivers needed, acked by the
hwmon maintainer
- xillybus driver updates
- binder driver updates
- extcon driver updates
- dma_buf module namespaces added (will cause a build error in arm64
for allmodconfig, but that change is on its way through the drm
tree)
- lkdtm driver updates
- pvpanic driver updates
- phy driver updates
- virt acrn and nitr_enclaves driver updates
- smaller char and misc driver updates"
* tag 'char-misc-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (386 commits)
comedi: dt9812: fix DMA buffers on stack
comedi: ni_usb6501: fix NULL-deref in command paths
arm64: errata: Enable TRBE workaround for write to out-of-range address
arm64: errata: Enable workaround for TRBE overwrite in FILL mode
coresight: trbe: Work around write to out of range
coresight: trbe: Make sure we have enough space
coresight: trbe: Add a helper to determine the minimum buffer size
coresight: trbe: Workaround TRBE errata overwrite in FILL mode
coresight: trbe: Add infrastructure for Errata handling
coresight: trbe: Allow driver to choose a different alignment
coresight: trbe: Decouple buffer base from the hardware base
coresight: trbe: Add a helper to pad a given buffer area
coresight: trbe: Add a helper to calculate the trace generated
coresight: trbe: Defer the probe on offline CPUs
coresight: trbe: Fix incorrect access of the sink specific data
coresight: etm4x: Add ETM PID for Kryo-5XX
coresight: trbe: Prohibit trace before disabling TRBE
coresight: trbe: End the AUX handle on truncation
coresight: trbe: Do not truncate buffer on IRQ
coresight: trbe: Fix handling of spurious interrupts
...
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Merge tag 'selinux-pr-20211101' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux updates from Paul Moore:
- Add LSM/SELinux/Smack controls and auditing for io-uring.
As usual, the individual commit descriptions have more detail, but we
were basically missing two things which we're adding here:
+ establishment of a proper audit context so that auditing of
io-uring ops works similarly to how it does for syscalls (with
some io-uring additions because io-uring ops are *not* syscalls)
+ additional LSM hooks to enable access control points for some of
the more unusual io-uring features, e.g. credential overrides.
The additional audit callouts and LSM hooks were done in conjunction
with the io-uring folks, based on conversations and RFC patches
earlier in the year.
- Fixup the binder credential handling so that the proper credentials
are used in the LSM hooks; the commit description and the code
comment which is removed in these patches are helpful to understand
the background and why this is the proper fix.
- Enable SELinux genfscon policy support for securityfs, allowing
improved SELinux filesystem labeling for other subsystems which make
use of securityfs, e.g. IMA.
* tag 'selinux-pr-20211101' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
security: Return xattr name from security_dentry_init_security()
selinux: fix a sock regression in selinux_ip_postroute_compat()
binder: use cred instead of task for getsecid
binder: use cred instead of task for selinux checks
binder: use euid from cred instead of using task
LSM: Avoid warnings about potentially unused hook variables
selinux: fix all of the W=1 build warnings
selinux: make better use of the nf_hook_state passed to the NF hooks
selinux: fix race condition when computing ocontext SIDs
selinux: remove unneeded ipv6 hook wrappers
selinux: remove the SELinux lockdown implementation
selinux: enable genfscon labeling for securityfs
Smack: Brutalist io_uring support
selinux: add support for the io_uring access controls
lsm,io_uring: add LSM hooks to io_uring
io_uring: convert io_uring to the secure anon inode interface
fs: add anon_inode_getfile_secure() similar to anon_inode_getfd_secure()
audit: add filtering for io_uring records
audit,io_uring,io-wq: add some basic audit support to io_uring
audit: prepare audit_context for use in calling contexts beyond syscalls
When freeing txn buffers, binder_transaction_buffer_release()
attempts to detect whether the current context is the target by
comparing current->group_leader to proc->tsk. This is an unreliable
test. Instead explicitly pass an 'is_failure' boolean.
Detecting the sender was being used as a way to tell if the
transaction failed to be sent. When cleaning up after
failing to send a transaction, there is no need to close
the fds associated with a BINDER_TYPE_FDA object. Now
'is_failure' can be used to accurately detect this case.
Fixes: 44d8047f1d ("binder: use standard functions to allocate fds")
Cc: stable <stable@vger.kernel.org>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20211015233811.3532235-1-tkjos@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use the 'struct cred' saved at binder_open() to lookup
the security ID via security_cred_getsecid(). This
ensures that the security context that opened binder
is the one used to generate the secctx.
Cc: stable@vger.kernel.org # 5.4+
Fixes: ec74136ded ("binder: create node flag to request sender's security context")
Signed-off-by: Todd Kjos <tkjos@google.com>
Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Reported-by: kernel test robot <lkp@intel.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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: 79af73079d ("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>
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: 457b9a6f09 ("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>
During BC_FREE_BUFFER processing, the BINDER_TYPE_FDA object
cleanup may close 1 or more fds. The close operations are
completed using the task work mechanism -- which means the thread
needs to return to userspace or the file object may never be
dereferenced -- which can lead to hung processes.
Force the binder thread back to userspace if an fd is closed during
BC_FREE_BUFFER handling.
Fixes: 80cd795630 ("binder: fix use-after-free due to ksys_close() during fdget()")
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Martijn Coenen <maco@android.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20210830195146.587206-1-tkjos@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently cgroup freezer is used to freeze the application threads, and
BINDER_FREEZE is used to freeze the corresponding binder interface.
There's already a mechanism in ioctl(BINDER_FREEZE) to wait for any
existing transactions to drain out before actually freezing the binder
interface.
But freezing an app requires 2 steps, freezing the binder interface with
ioctl(BINDER_FREEZE) and then freezing the application main threads with
cgroupfs. This is not an atomic operation. The following race issue
might happen.
1) Binder interface is frozen by ioctl(BINDER_FREEZE);
2) Main thread A initiates a new sync binder transaction to process B;
3) Main thread A is frozen by "echo 1 > cgroup.freeze";
4) The response from process B reaches the frozen thread, which will
unexpectedly fail.
This patch provides a mechanism to check if there's any new pending
transaction happening between ioctl(BINDER_FREEZE) and freezing the
main thread. If there's any, the main thread freezing operation can
be rolled back to finish the pending transaction.
Furthermore, the response might reach the binder driver before the
rollback actually happens. That will still cause failed transaction.
As the other process doesn't wait for another response of the response,
the response transaction failure can be fixed by treating the response
transaction like an oneway/async one, allowing it to reach the frozen
thread. And it will be consumed when the thread gets unfrozen later.
NOTE: This patch reuses the existing definition of struct
binder_frozen_status_info but expands the bit assignments of __u32
member sync_recv.
To ensure backward compatibility, bit 0 of sync_recv still indicates
there's an outstanding sync binder transaction. This patch adds new
information to bit 1 of sync_recv, indicating the binder transaction
happens exactly when there's a race.
If an existing userspace app runs on a new kernel, a sync binder call
will set bit 0 of sync_recv so ioctl(BINDER_GET_FROZEN_INFO) still
return the expected value (true). The app just doesn't check bit 1
intentionally so it doesn't have the ability to tell if there's a race.
This behavior is aligned with what happens on an old kernel which
doesn't set bit 1 at all.
A new userspace app can 1) check bit 0 to know if there's a sync binder
transaction happened when being frozen - same as before; and 2) check
bit 1 to know if that sync binder transaction happened exactly when
there's a race - a new information for rollback decision.
the same time, confirmed the pending transactions succeeded.
Fixes: 432ff1e916 ("binder: BINDER_FREEZE ioctl")
Acked-by: Todd Kjos <tkjos@google.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Li Li <dualli@google.com>
Test: stress test with apps being frozen and initiating binder calls at
Link: https://lore.kernel.org/r/20210910164210.2282716-2-dualli@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In the case of a failed transaction, only the thread and process id are
logged. Add the handle info for the reference to the target node in user
error log to aid debugging.
Acked-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Ramji Jiyani <ramjiyani@google.com>
Link: https://lore.kernel.org/r/20210802220446.1938347-1-ramjiyani@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
All the other ioctl paths return EFAULT in case the
copy_from_user/copy_to_user call fails, make oneway spam detection
follow the same paradigm.
Fixes: a7dc1e6f99 ("binder: tell userspace to dump current backtrace when detected oneway spamming")
Acked-by: Todd Kjos <tkjos@google.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Luca Stefani <luca.stefani.ge1@gmail.com>
Link: https://lore.kernel.org/r/20210506193726.45118-1-luca.stefani.ge1@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'selinux-pr-20210426' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux updates from Paul Moore:
- Add support for measuring the SELinux state and policy capabilities
using IMA.
- A handful of SELinux/NFS patches to compare the SELinux state of one
mount with a set of mount options. Olga goes into more detail in the
patch descriptions, but this is important as it allows more
flexibility when using NFS and SELinux context mounts.
- Properly differentiate between the subjective and objective LSM
credentials; including support for the SELinux and Smack. My clumsy
attempt at a proper fix for AppArmor didn't quite pass muster so John
is working on a proper AppArmor patch, in the meantime this set of
patches shouldn't change the behavior of AppArmor in any way. This
change explains the bulk of the diffstat beyond security/.
- Fix a problem where we were not properly terminating the permission
list for two SELinux object classes.
* tag 'selinux-pr-20210426' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
selinux: add proper NULL termination to the secclass_map permissions
smack: differentiate between subjective and objective task credentials
selinux: clarify task subjective and objective credentials
lsm: separate security_task_getsecid() into subjective and objective variants
nfs: account for selinux security context when deciding to share superblock
nfs: remove unneeded null check in nfs_fill_super()
lsm,selinux: add new hook to compare new mount to an existing mount
selinux: fix misspellings using codespell tool
selinux: fix misspellings using codespell tool
selinux: measure state and policy capabilities
selinux: Allow context mounts for unpriviliged overlayfs
When async binder buffer got exhausted, some normal oneway transactions
will also be discarded and may cause system or application failures. By
that time, the binder debug information we dump may not be relevant to
the root cause. And this issue is difficult to debug if without the
backtrace of the thread sending spam.
This change will send BR_ONEWAY_SPAM_SUSPECT to userspace when oneway
spamming is detected, request to dump current backtrace. Oneway spamming
will be reported only once when exceeding the threshold (target process
dips below 80% of its oneway space, and current process is responsible for
either more than 50 transactions, or more than 50% of the oneway space).
And the detection will restart when the async buffer has returned to a
healthy state.
Acked-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Hang Lu <hangl@codeaurora.org>
Link: https://lore.kernel.org/r/1617961246-4502-3-git-send-email-hangl@codeaurora.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add BR_FROZEN_REPLY in binder_return_strings to support stat function.
Fixes: ae28c1be1e ("binder: BINDER_GET_FROZEN_INFO ioctl")
Acked-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Hang Lu <hangl@codeaurora.org>
Link: https://lore.kernel.org/r/1617961246-4502-2-git-send-email-hangl@codeaurora.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
User space needs to know if binder transactions occurred to frozen
processes. Introduce a new BINDER_GET_FROZEN ioctl and keep track of
transactions occurring to frozen proceses.
Signed-off-by: Marco Ballesio <balejs@google.com>
Signed-off-by: Li Li <dualli@google.com>
Acked-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20210316011630.1121213-4-dualli@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
when interrupted by a signal, binder_wait_for_work currently returns
-ERESTARTSYS. This error code isn't propagated to user space, but a way
to handle interruption due to signals must be provided to code using
this API.
Replace this instance of -ERESTARTSYS with -EINTR, which is propagated
to user space.
binder_wait_for_work
Signed-off-by: Marco Ballesio <balejs@google.com>
Signed-off-by: Li Li <dualli@google.com>
Test: built, booted, interrupted a worker thread within
Acked-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20210316011630.1121213-3-dualli@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Frozen tasks can't process binder transactions, so a way is required to
inform transmitting ends of communication failures due to the frozen
state of their receiving counterparts. Additionally, races are possible
between transitions to frozen state and binder transactions enqueued to
a specific process.
Implement BINDER_FREEZE ioctl for user space to inform the binder driver
about the intention to freeze or unfreeze a process. When the ioctl is
called, block the caller until any pending binder transactions toward
the target process are flushed. Return an error to transactions to
processes marked as frozen.
Co-developed-by: Todd Kjos <tkjos@google.com>
Acked-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Marco Ballesio <balejs@google.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Li Li <dualli@google.com>
Link: https://lore.kernel.org/r/20210316011630.1121213-2-dualli@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Of the three LSMs that implement the security_task_getsecid() LSM
hook, all three LSMs provide the task's objective security
credentials. This turns out to be unfortunate as most of the hook's
callers seem to expect the task's subjective credentials, although
a small handful of callers do correctly expect the objective
credentials.
This patch is the first step towards fixing the problem: it splits
the existing security_task_getsecid() hook into two variants, one
for the subjective creds, one for the objective creds.
void security_task_getsecid_subj(struct task_struct *p,
u32 *secid);
void security_task_getsecid_obj(struct task_struct *p,
u32 *secid);
While this patch does fix all of the callers to use the correct
variant, in order to keep this patch focused on the callers and to
ease review, the LSMs continue to use the same implementation for
both hooks. The net effect is that this patch should not change
the behavior of the kernel in any way, it will be up to the latter
LSM specific patches in this series to change the hook
implementations and return the correct credentials.
Acked-by: Mimi Zohar <zohar@linux.ibm.com> (IMA)
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Pull execve updates from Eric Biederman:
"This set of changes ultimately fixes the interaction of posix file
lock and exec. Fundamentally most of the change is just moving where
unshare_files is called during exec, and tweaking the users of
files_struct so that the count of files_struct is not unnecessarily
played with.
Along the way fcheck and related helpers were renamed to more
accurately reflect what they do.
There were also many other small changes that fell out, as this is the
first time in a long time much of this code has been touched.
Benchmarks haven't turned up any practical issues but Al Viro has
observed a possibility for a lot of pounding on task_lock. So I have
some changes in progress to convert put_files_struct to always rcu
free files_struct. That wasn't ready for the merge window so that will
have to wait until next time"
* 'exec-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (27 commits)
exec: Move io_uring_task_cancel after the point of no return
coredump: Document coredump code exclusively used by cell spufs
file: Remove get_files_struct
file: Rename __close_fd_get_file close_fd_get_file
file: Replace ksys_close with close_fd
file: Rename __close_fd to close_fd and remove the files parameter
file: Merge __alloc_fd into alloc_fd
file: In f_dupfd read RLIMIT_NOFILE once.
file: Merge __fd_install into fd_install
proc/fd: In fdinfo seq_show don't use get_files_struct
bpf/task_iter: In task_file_seq_get_next use task_lookup_next_fd_rcu
proc/fd: In proc_readfd_common use task_lookup_next_fd_rcu
file: Implement task_lookup_next_fd_rcu
kcmp: In get_file_raw_ptr use task_lookup_fd_rcu
proc/fd: In tid_fd_mode use task_lookup_fd_rcu
file: Implement task_lookup_fd_rcu
file: Rename fcheck lookup_fd_rcu
file: Replace fcheck_files with files_lookup_fd_rcu
file: Factor files_lookup_fd_locked out of fcheck_files
file: Rename __fcheck_files to files_lookup_fd_raw
...
The function close_fd_get_file is explicitly a variant of
__close_fd[1]. Now that __close_fd has been renamed close_fd, rename
close_fd_get_file to be consistent with close_fd.
When __alloc_fd, __close_fd and __fd_install were introduced the
double underscore indicated that the function took a struct
files_struct parameter. The function __close_fd_get_file never has so
the naming has always been inconsistent. This just cleans things up
so there are not any lingering mentions or references __close_fd left
in the code.
[1] 80cd795630 ("binder: fix use-after-free due to ksys_close() during fdget()")
Link: https://lkml.kernel.org/r/20201120231441.29911-23-ebiederm@xmission.com
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Add a per-transaction flag to indicate that the buffer
must be cleared when the transaction is complete to
prevent copies of sensitive data from being preserved
in memory.
Signed-off-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20201120233743.3617529-1-tkjos@google.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since the original trace_binder_transaction_received cannot
precisely present the real finished time of transaction, adding a
trace_binder_txn_latency_free at the point of free transaction
may be more close to it.
Signed-off-by: Frankie.Chang <Frankie.Chang@mediatek.com>
Acked-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/1605063764-12930-3-git-send-email-Frankie.Chang@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Moving all structs to header file makes module more
extendable, and makes all these structs to be defined
in the same file.
Signed-off-by: Frankie.Chang <Frankie.Chang@mediatek.com>
Acked-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/1605063764-12930-2-git-send-email-Frankie.Chang@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Depending on the context, the error return value
here (extra_buffers_size < added_size) should be
negative.
Acked-by: Martijn Coenen <maco@android.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com>
Link: https://lore.kernel.org/r/20201026110314.135481-1-zhangqilong3@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
A previous commit changed the notification mode from true/false to an
int, allowing notify-no, notify-yes, or signal-notify. This was
backwards compatible in the sense that any existing true/false user
would translate to either 0 (on notification sent) or 1, the latter
which mapped to TWA_RESUME. TWA_SIGNAL was assigned a value of 2.
Clean this up properly, and define a proper enum for the notification
mode. Now we have:
- TWA_NONE. This is 0, same as before the original change, meaning no
notification requested.
- TWA_RESUME. This is 1, same as before the original change, meaning
that we use TIF_NOTIFY_RESUME.
- TWA_SIGNAL. This uses TIF_SIGPENDING/JOBCTL_TASK_WORK for the
notification.
Clean up all the callers, switching their 0/1/false/true to using the
appropriate TWA_* mode for notifications.
Fixes: e91b481623 ("task_work: teach task_work_add() to do signal_wake_up()")
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When releasing a thread todo list when tearing down
a binder_proc, the following race was possible which
could result in a use-after-free:
1. Thread 1: enter binder_release_work from binder_thread_release
2. Thread 2: binder_update_ref_for_handle() -> binder_dec_node_ilocked()
3. Thread 2: dec nodeA --> 0 (will free node)
4. Thread 1: ACQ inner_proc_lock
5. Thread 2: block on inner_proc_lock
6. Thread 1: dequeue work (BINDER_WORK_NODE, part of nodeA)
7. Thread 1: REL inner_proc_lock
8. Thread 2: ACQ inner_proc_lock
9. Thread 2: todo list cleanup, but work was already dequeued
10. Thread 2: free node
11. Thread 2: REL inner_proc_lock
12. Thread 1: deref w->type (UAF)
The problem was that for a BINDER_WORK_NODE, the binder_work element
must not be accessed after releasing the inner_proc_lock while
processing the todo list elements since another thread might be
handling a deref on the node containing the binder_work element
leading to the node being freed.
Signed-off-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20201009232455.4054810-1-tkjos@google.com
Cc: <stable@vger.kernel.org> # 4.14, 4.19, 5.4, 5.8
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The most common cause of the binder transaction buffer filling up is a
client rapidly firing oneway transactions into a process, before it has
a chance to handle them. Yet the root cause of this is often hard to
debug, because either the system or the app will stop, and by that time
binder debug information we dump in bugreports is no longer relevant.
This change warns as soon as a process dips below 80% of its oneway
space (less than 100kB available in the configuration), when any one
process is responsible for either more than 50 transactions, or more
than 50% of the oneway space.
Signed-off-by: Martijn Coenen <maco@android.com>
Acked-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20200821122544.1277051-1-maco@android.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
While binder transactions with the same binder_proc as sender and recipient
are forbidden, transactions with the same task_struct as sender and
recipient are possible (even though currently there is a weird check in
binder_transaction() that rejects them in the target==0 case).
Therefore, task_struct identities can't be used to distinguish whether
the caller is running in the context of the sender or the recipient.
Since I see no easy way to make this WARN_ON() useful and correct, let's
just remove it.
Fixes: 44d8047f1d ("binder: use standard functions to allocate fds")
Reported-by: syzbot+e113a0b970b7b3f394ba@syzkaller.appspotmail.com
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Jann Horn <jannh@google.com>
Link: https://lore.kernel.org/r/20200806165359.2381483-1-jannh@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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: 457b9a6f09 ("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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The binder driver makes the assumption proc->context pointer is invariant after
initialization (as documented in the kerneldoc header for struct proc).
However, in commit f0fe2c0f05 ("binder: prevent UAF for binderfs devices II")
proc->context is set to NULL during binder_deferred_release().
Another proc was in the middle of setting up a transaction to the dying
process and crashed on a NULL pointer deref on "context" which is a local
set to &proc->context:
new_ref->data.desc = (node == context->binder_context_mgr_node) ? 0 : 1;
Here's the stack:
[ 5237.855435] Call trace:
[ 5237.855441] binder_get_ref_for_node_olocked+0x100/0x2ec
[ 5237.855446] binder_inc_ref_for_node+0x140/0x280
[ 5237.855451] binder_translate_binder+0x1d0/0x388
[ 5237.855456] binder_transaction+0x2228/0x3730
[ 5237.855461] binder_thread_write+0x640/0x25bc
[ 5237.855466] binder_ioctl_write_read+0xb0/0x464
[ 5237.855471] binder_ioctl+0x30c/0x96c
[ 5237.855477] do_vfs_ioctl+0x3e0/0x700
[ 5237.855482] __arm64_sys_ioctl+0x78/0xa4
[ 5237.855488] el0_svc_common+0xb4/0x194
[ 5237.855493] el0_svc_handler+0x74/0x98
[ 5237.855497] el0_svc+0x8/0xc
The fix is to move the kfree of the binder_device to binder_free_proc()
so the binder_device is freed when we know there are no references
remaining on the binder_proc.
Fixes: f0fe2c0f05 ("binder: prevent UAF for binderfs devices II")
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200622200715.114382-1-tkjos@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is a necessary follow up to the first fix I proposed and we merged
in 2669b8b0c7 ("binder: prevent UAF for binderfs devices"). I have been
overly optimistic that the simple fix I proposed would work. But alas,
ihold() + iput() won't work since the inodes won't survive the
destruction of the superblock.
So all we get with my prior fix is a different race with a tinier
race-window but it doesn't solve the issue. Fwiw, the problem lies with
generic_shutdown_super(). It even has this cozy Al-style comment:
if (!list_empty(&sb->s_inodes)) {
printk("VFS: Busy inodes after unmount of %s. "
"Self-destruct in 5 seconds. Have a nice day...\n",
sb->s_id);
}
On binder_release(), binder_defer_work(proc, BINDER_DEFERRED_RELEASE) is
called which punts the actual cleanup operation to a workqueue. At some
point, binder_deferred_func() will be called which will end up calling
binder_deferred_release() which will retrieve and cleanup the
binder_context attach to this struct binder_proc.
If we trace back where this binder_context is attached to binder_proc we
see that it is set in binder_open() and is taken from the struct
binder_device it is associated with. This obviously assumes that the
struct binder_device that context is attached to is _never_ freed. While
that might be true for devtmpfs binder devices it is most certainly
wrong for binderfs binder devices.
So, assume binder_open() is called on a binderfs binder devices. We now
stash away the struct binder_context associated with that struct
binder_devices:
proc->context = &binder_dev->context;
/* binderfs stashes devices in i_private */
if (is_binderfs_device(nodp)) {
binder_dev = nodp->i_private;
info = nodp->i_sb->s_fs_info;
binder_binderfs_dir_entry_proc = info->proc_log_dir;
} else {
.
.
.
proc->context = &binder_dev->context;
Now let's assume that the binderfs instance for that binder devices is
shutdown via umount() and/or the mount namespace associated with it goes
away. As long as there is still an fd open for that binderfs binder
device things are fine. But let's assume we now close the last fd for
that binderfs binder device. Now binder_release() is called and punts to
the workqueue. Assume that the workqueue has quite a bit of stuff to do
and doesn't get to cleaning up the struct binder_proc and the associated
struct binder_context with it for that binderfs binder device right
away. In the meantime, the VFS is killing the super block and is
ultimately calling sb->evict_inode() which means it will call
binderfs_evict_inode() which does:
static void binderfs_evict_inode(struct inode *inode)
{
struct binder_device *device = inode->i_private;
struct binderfs_info *info = BINDERFS_I(inode);
clear_inode(inode);
if (!S_ISCHR(inode->i_mode) || !device)
return;
mutex_lock(&binderfs_minors_mutex);
--info->device_count;
ida_free(&binderfs_minors, device->miscdev.minor);
mutex_unlock(&binderfs_minors_mutex);
kfree(device->context.name);
kfree(device);
}
thereby freeing the struct binder_device including struct
binder_context.
Now the workqueue finally has time to get around to cleaning up struct
binder_proc and is now trying to access the associate struct
binder_context. Since it's already freed it will OOPs.
Fix this by introducing a refounct on binder devices.
This is an alternative fix to 51d8a7eca6 ("binder: prevent UAF read in
print_binder_transaction_log_entry()").
Fixes: 3ad20fe393 ("binder: implement binderfs")
Fixes: 2669b8b0c7 ("binder: prevent UAF for binderfs devices")
Fixes: 03e2e07e38 ("binder: Make transaction_log available in binderfs")
Related : 51d8a7eca6 ("binder: prevent UAF read in print_binder_transaction_log_entry()")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20200303164340.670054-1-christian.brauner@ubuntu.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
On binder_release(), binder_defer_work(proc, BINDER_DEFERRED_RELEASE) is
called which punts the actual cleanup operation to a workqueue. At some
point, binder_deferred_func() will be called which will end up calling
binder_deferred_release() which will retrieve and cleanup the
binder_context attach to this struct binder_proc.
If we trace back where this binder_context is attached to binder_proc we
see that it is set in binder_open() and is taken from the struct
binder_device it is associated with. This obviously assumes that the
struct binder_device that context is attached to is _never_ freed. While
that might be true for devtmpfs binder devices it is most certainly
wrong for binderfs binder devices.
So, assume binder_open() is called on a binderfs binder devices. We now
stash away the struct binder_context associated with that struct
binder_devices:
proc->context = &binder_dev->context;
/* binderfs stashes devices in i_private */
if (is_binderfs_device(nodp)) {
binder_dev = nodp->i_private;
info = nodp->i_sb->s_fs_info;
binder_binderfs_dir_entry_proc = info->proc_log_dir;
} else {
.
.
.
proc->context = &binder_dev->context;
Now let's assume that the binderfs instance for that binder devices is
shutdown via umount() and/or the mount namespace associated with it goes
away. As long as there is still an fd open for that binderfs binder
device things are fine. But let's assume we now close the last fd for
that binderfs binder device. Now binder_release() is called and punts to
the workqueue. Assume that the workqueue has quite a bit of stuff to do
and doesn't get to cleaning up the struct binder_proc and the associated
struct binder_context with it for that binderfs binder device right
away. In the meantime, the VFS is killing the super block and is
ultimately calling sb->evict_inode() which means it will call
binderfs_evict_inode() which does:
static void binderfs_evict_inode(struct inode *inode)
{
struct binder_device *device = inode->i_private;
struct binderfs_info *info = BINDERFS_I(inode);
clear_inode(inode);
if (!S_ISCHR(inode->i_mode) || !device)
return;
mutex_lock(&binderfs_minors_mutex);
--info->device_count;
ida_free(&binderfs_minors, device->miscdev.minor);
mutex_unlock(&binderfs_minors_mutex);
kfree(device->context.name);
kfree(device);
}
thereby freeing the struct binder_device including struct
binder_context.
Now the workqueue finally has time to get around to cleaning up struct
binder_proc and is now trying to access the associate struct
binder_context. Since it's already freed it will OOPs.
Fix this by holding an additional reference to the inode that is only
released once the workqueue is done cleaning up struct binder_proc. This
is an easy alternative to introducing separate refcounting on struct
binder_device which we can always do later if it becomes necessary.
This is an alternative fix to 51d8a7eca6 ("binder: prevent UAF read in
print_binder_transaction_log_entry()").
Fixes: 3ad20fe393 ("binder: implement binderfs")
Fixes: 03e2e07e38 ("binder: Make transaction_log available in binderfs")
Related : 51d8a7eca6 ("binder: prevent UAF read in print_binder_transaction_log_entry()")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'for-5.6/io_uring-vfs-2020-01-29' of git://git.kernel.dk/linux-block
Pull io_uring updates from Jens Axboe:
- Support for various new opcodes (fallocate, openat, close, statx,
fadvise, madvise, openat2, non-vectored read/write, send/recv, and
epoll_ctl)
- Faster ring quiesce for fileset updates
- Optimizations for overflow condition checking
- Support for max-sized clamping
- Support for probing what opcodes are supported
- Support for io-wq backend sharing between "sibling" rings
- Support for registering personalities
- Lots of little fixes and improvements
* tag 'for-5.6/io_uring-vfs-2020-01-29' of git://git.kernel.dk/linux-block: (64 commits)
io_uring: add support for epoll_ctl(2)
eventpoll: support non-blocking do_epoll_ctl() calls
eventpoll: abstract out epoll_ctl() handler
io_uring: fix linked command file table usage
io_uring: support using a registered personality for commands
io_uring: allow registering credentials
io_uring: add io-wq workqueue sharing
io-wq: allow grabbing existing io-wq
io_uring/io-wq: don't use static creds/mm assignments
io-wq: make the io_wq ref counted
io_uring: fix refcounting with batched allocations at OOM
io_uring: add comment for drain_next
io_uring: don't attempt to copy iovec for READ/WRITE
io_uring: honor IOSQE_ASYNC for linked reqs
io_uring: prep req when do IOSQE_ASYNC
io_uring: use labeled array init in io_op_defs
io_uring: optimise sqe-to-req flags translation
io_uring: remove REQ_F_IO_DRAINED
io_uring: file switch work needs to get flushed on exit
io_uring: hide uring_fd in ctx
...
Since commit 43e23b6c0b ("debugfs: log errors when something goes wrong")
debugfs logs attempts to create existing files.
However binder attempts to create multiple debugfs files with
the same name when a single PID has multiple contexts, this leads
to log spamming during an Android boot (17 such messages during
boot on my system).
Fix this by checking if we already know the PID and only create
the debugfs entry for the first context per PID.
Do the same thing for binderfs for symmetry.
Signed-off-by: Martin Fuzzey <martin.fuzzey@flowbird.group>
Acked-by: Todd Kjos <tkjos@google.com>
Fixes: 43e23b6c0b ("debugfs: log errors when something goes wrong")
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/1578671054-5982-1-git-send-email-martin.fuzzey@flowbird.group
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Just one caller of this, and just use filp_close() there manually.
This is important to allow async close/removal of the fd.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For BINDER_TYPE_PTR and BINDER_TYPE_FDA transactions, the
num_valid local was calculated incorrectly causing the
range check in binder_validate_ptr() to miss out-of-bounds
offsets.
Fixes: bde4a19fc0 ("binder: use userspace pointer as base of buffer space")
Signed-off-by: Todd Kjos <tkjos@google.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191213202531.55010-1-tkjos@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Alessandro Astone