kernel/linux.git/drivers/android/binder.c, branch v5.16.1

binder: use wake_up_pollfree()

2021-12-09T18:49:56+00:00

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 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

binder: fix test regression due to sender_euid change

2021-11-17T15:08:52+00:00

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 Signed-off-by: Todd Kjos Change-Id: I9b1769a3510fed250bb21859ef8beebabe034c66 Link: https://lore.kernel.org/r/20211112180720.2858135-1-tkjos@google.com Signed-off-by: Greg Kroah-Hartman

Merge tag 'char-misc-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

2021-11-04T15:21:47+00:00

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 ...

Merge tag 'selinux-pr-20211101' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

2021-11-02T04:06:18+00:00

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

binder: don't detect sender/target during buffer cleanup

2021-10-19T07:38:55+00:00

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: 44d8047f1d87 ("binder: use standard functions to allocate fds") Cc: stable Acked-by: Christian Brauner Signed-off-by: Todd Kjos Link: https://lore.kernel.org/r/20211015233811.3532235-1-tkjos@google.com Signed-off-by: Greg Kroah-Hartman

binder: use cred instead of task for getsecid

2021-10-15T00:48:43+00:00

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: ec74136ded79 ("binder: create node flag to request sender's security context") Signed-off-by: Todd Kjos Suggested-by: Stephen Smalley Reported-by: kernel test robot Acked-by: Casey Schaufler Signed-off-by: Paul Moore

binder: use cred instead of task for selinux checks

2021-10-15T00:48:04+00:00

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 Signed-off-by: Todd Kjos Acked-by: Casey Schaufler Signed-off-by: Paul Moore

binder: use euid from cred instead of using task

2021-10-14T21:19:40+00:00

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 Suggested-by: Stephen Smalley Suggested-by: Jann Horn Acked-by: Casey Schaufler Signed-off-by: Paul Moore

binder: make sure fd closes complete

2021-09-14T07:02:13+00:00

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: 80cd795630d6 ("binder: fix use-after-free due to ksys_close() during fdget()") Cc: stable Reviewed-by: Martijn Coenen Acked-by: Christian Brauner Signed-off-by: Todd Kjos Link: https://lore.kernel.org/r/20210830195146.587206-1-tkjos@google.com Signed-off-by: Greg Kroah-Hartman

binder: fix freeze race

2021-09-14T06:46:08+00:00

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: 432ff1e91694 ("binder: BINDER_FREEZE ioctl") Acked-by: Todd Kjos Cc: stable Signed-off-by: Li Li 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