kernel/linux.git/drivers/android/binder.c, branch v6.6.23

binder: signal epoll threads of self-work

2024-02-23T08:25:04+00:00

commit 97830f3c3088638ff90b20dfba2eb4d487bf14d7 upstream. In (e)poll mode, threads often depend on I/O events to determine when data is ready for consumption. Within binder, a thread may initiate a command via BINDER_WRITE_READ without a read buffer and then make use of epoll_wait() or similar to consume any responses afterwards. It is then crucial that epoll threads are signaled via wakeup when they queue their own work. Otherwise, they risk waiting indefinitely for an event leaving their work unhandled. What is worse, subsequent commands won't trigger a wakeup either as the thread has pending work. Fixes: 457b9a6f09f0 ("Staging: android: add binder driver") Cc: Arve Hjønnevåg Cc: Martijn Coenen Cc: Alice Ryhl Cc: Steven Moreland Cc: stable@vger.kernel.org # v4.19+ Signed-off-by: Carlos Llamas Link: https://lore.kernel.org/r/20240131215347.1808751-1-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman

binder: use EPOLLERR from eventpoll.h

2024-01-20T10:51:48+00:00

commit 6ac061db9c58ca5b9270b1b3940d2464fb3ff183 upstream. Use EPOLLERR instead of POLLERR to make sure it is cast to the correct __poll_t type. This fixes the following sparse issue: drivers/android/binder.c:5030:24: warning: incorrect type in return expression (different base types) drivers/android/binder.c:5030:24: expected restricted __poll_t drivers/android/binder.c:5030:24: got int Fixes: f88982679f54 ("binder: check for binder_thread allocation failure in binder_poll()") Cc: stable@vger.kernel.org Cc: Eric Biggers Reviewed-by: Alice Ryhl Signed-off-by: Carlos Llamas Link: https://lore.kernel.org/r/20231201172212.1813387-2-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman

binder: fix memory leaks of spam and pending work

2023-10-05T10:48:08+00:00

A transaction complete work is allocated and queued for each transaction. Under certain conditions the work->type might be marked as BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT to notify userspace about potential spamming threads or as BINDER_WORK_TRANSACTION_PENDING when the target is currently frozen. However, these work types are not being handled in binder_release_work() so they will leak during a cleanup. This was reported by syzkaller with the following kmemleak dump: BUG: memory leak unreferenced object 0xffff88810e2d6de0 (size 32): comm "syz-executor338", pid 5046, jiffies 4294968230 (age 13.590s) hex dump (first 32 bytes): e0 6d 2d 0e 81 88 ff ff e0 6d 2d 0e 81 88 ff ff .m-......m-..... 04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [] kmalloc_trace+0x25/0x90 mm/slab_common.c:1114 [] kmalloc include/linux/slab.h:599 [inline] [] kzalloc include/linux/slab.h:720 [inline] [] binder_transaction+0x573/0x4050 drivers/android/binder.c:3152 [] binder_thread_write+0x6b5/0x1860 drivers/android/binder.c:4010 [] binder_ioctl_write_read drivers/android/binder.c:5066 [inline] [] binder_ioctl+0x1b2c/0x3cf0 drivers/android/binder.c:5352 [] vfs_ioctl fs/ioctl.c:51 [inline] [] __do_sys_ioctl fs/ioctl.c:871 [inline] [] __se_sys_ioctl fs/ioctl.c:857 [inline] [] __x64_sys_ioctl+0xf2/0x140 fs/ioctl.c:857 [] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 [] entry_SYSCALL_64_after_hwframe+0x63/0xcd Fix the leaks by kfreeing these work types in binder_release_work() and handle them as a BINDER_WORK_TRANSACTION_COMPLETE cleanup. Cc: stable@vger.kernel.org Fixes: 0567461a7a6e ("binder: return pending info for frozen async txns") Fixes: a7dc1e6f99df ("binder: tell userspace to dump current backtrace when detected oneway spamming") Reported-by: syzbot+7f10c1653e35933c0f1e@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=7f10c1653e35933c0f1e Suggested-by: Alice Ryhl Signed-off-by: Carlos Llamas Reviewed-by: Alice Ryhl Acked-by: Todd Kjos Link: https://lore.kernel.org/r/20230922175138.230331-1-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman

Merge 6.5-rc6 into char-misc-next

2023-08-13T20:14:51+00:00

We need the char/misc fixes in here as well to build on top of. Signed-off-by: Greg Kroah-Hartman

android: Remove error checking for debugfs_create_dir()

2023-08-04T13:28:01+00:00

It is expected that most callers should _ignore_ the errors return by debugfs_create_dir() in binder_init(). Signed-off-by: Wang Ming Link: https://lore.kernel.org/r/20230713080649.1893-1-machel@vivo.com Signed-off-by: Greg Kroah-Hartman

binder: fix memory leak in binder_init()

2023-08-04T13:25:01+00:00

In binder_init(), the destruction of binder_alloc_shrinker_init() is not performed in the wrong path, which will cause memory leaks. So this commit introduces binder_alloc_shrinker_exit() and calls it in the wrong path to fix that. Signed-off-by: Qi Zheng Acked-by: Carlos Llamas Fixes: f2517eb76f1f ("android: binder: Add global lru shrinker to binder") Cc: stable Link: https://lore.kernel.org/r/20230625154937.64316-1-qi.zheng@linux.dev Signed-off-by: Greg Kroah-Hartman

Merge v6.4-rc4 into char-misc-next

2023-05-28T13:55:30+00:00

We need the binder fixes in here for future changes and testing. Signed-off-by: Greg Kroah-Hartman

Binder: Add async from to transaction record

2023-05-13T11:38:12+00:00

This commit adds support for getting the pid and tid information of the sender for asynchronous transfers in binderfs transfer records. In previous versions, it was not possible to obtain this information from the transfer records. While this information may not be necessary for all use cases, it can be useful in some scenarios. Signed-off-by: Chuang Zhang Acked-by: Carlos Llamas Link: https://lore.kernel.org/r/0c1e8bd37c68dd1518bb737b06b768cde9659386.1682333709.git.zhangchuang3@xiaomi.com Signed-off-by: Greg Kroah-Hartman

Binder: Add timestamp to transaction record

2023-05-13T11:38:12+00:00

This patch adds a timestamp field to the binder_transaction structure to track the time consumed during transmission when reading binder_transaction records. Signed-off-by: Chuang Zhang Acked-by: Carlos Llamas Link: https://lore.kernel.org/r/5ac8c0d09392290be789423f0dd78a520b830fab.1682333709.git.zhangchuang3@xiaomi.com Signed-off-by: Greg Kroah-Hartman

binder: fix UAF caused by faulty buffer cleanup

2023-05-13T11:29:27+00:00

In binder_transaction_buffer_release() the 'failed_at' offset indicates the number of objects to clean up. However, this function was changed by commit 44d8047f1d87 ("binder: use standard functions to allocate fds"), to release all the objects in the buffer when 'failed_at' is zero. This introduced an issue when a transaction buffer is released without any objects having been processed so far. In this case, 'failed_at' is indeed zero yet it is misinterpreted as releasing the entire buffer. This leads to use-after-free errors where nodes are incorrectly freed and subsequently accessed. Such is the case in the following KASAN report: ================================================================== BUG: KASAN: slab-use-after-free in binder_thread_read+0xc40/0x1f30 Read of size 8 at addr ffff4faf037cfc58 by task poc/474 CPU: 6 PID: 474 Comm: poc Not tainted 6.3.0-12570-g7df047b3f0aa #5 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0x94/0xec show_stack+0x18/0x24 dump_stack_lvl+0x48/0x60 print_report+0xf8/0x5b8 kasan_report+0xb8/0xfc __asan_load8+0x9c/0xb8 binder_thread_read+0xc40/0x1f30 binder_ioctl+0xd9c/0x1768 __arm64_sys_ioctl+0xd4/0x118 invoke_syscall+0x60/0x188 [...] Allocated by task 474: kasan_save_stack+0x3c/0x64 kasan_set_track+0x2c/0x40 kasan_save_alloc_info+0x24/0x34 __kasan_kmalloc+0xb8/0xbc kmalloc_trace+0x48/0x5c binder_new_node+0x3c/0x3a4 binder_transaction+0x2b58/0x36f0 binder_thread_write+0x8e0/0x1b78 binder_ioctl+0x14a0/0x1768 __arm64_sys_ioctl+0xd4/0x118 invoke_syscall+0x60/0x188 [...] Freed by task 475: kasan_save_stack+0x3c/0x64 kasan_set_track+0x2c/0x40 kasan_save_free_info+0x38/0x5c __kasan_slab_free+0xe8/0x154 __kmem_cache_free+0x128/0x2bc kfree+0x58/0x70 binder_dec_node_tmpref+0x178/0x1fc binder_transaction_buffer_release+0x430/0x628 binder_transaction+0x1954/0x36f0 binder_thread_write+0x8e0/0x1b78 binder_ioctl+0x14a0/0x1768 __arm64_sys_ioctl+0xd4/0x118 invoke_syscall+0x60/0x188 [...] ================================================================== In order to avoid these issues, let's always calculate the intended 'failed_at' offset beforehand. This is renamed and wrapped in a helper function to make it clear and convenient. Fixes: 32e9f56a96d8 ("binder: don't detect sender/target during buffer cleanup") Reported-by: Zi Fan Tan Cc: stable@vger.kernel.org Signed-off-by: Carlos Llamas Acked-by: Todd Kjos Link: https://lore.kernel.org/r/20230505203020.4101154-1-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman