user/sven/linux.git/drivers/android, branch v6.1.152

binder: fix UAF caused by offsets overwrite

2024-09-12T09:10:26Z

commit 4df153652cc46545722879415937582028c18af5 upstream. Binder objects are processed and copied individually into the target buffer during transactions. Any raw data in-between these objects is copied as well. However, this raw data copy lacks an out-of-bounds check. If the raw data exceeds the data section size then the copy overwrites the offsets section. This eventually triggers an error that attempts to unwind the processed objects. However, at this point the offsets used to index these objects are now corrupted. Unwinding with corrupted offsets can result in decrements of arbitrary nodes and lead to their premature release. Other users of such nodes are left with a dangling pointer triggering a use-after-free. This issue is made evident by the following KASAN report (trimmed): ================================================================== BUG: KASAN: slab-use-after-free in _raw_spin_lock+0xe4/0x19c Write of size 4 at addr ffff47fc91598f04 by task binder-util/743 CPU: 9 UID: 0 PID: 743 Comm: binder-util Not tainted 6.11.0-rc4 #1 Hardware name: linux,dummy-virt (DT) Call trace: _raw_spin_lock+0xe4/0x19c binder_free_buf+0x128/0x434 binder_thread_write+0x8a4/0x3260 binder_ioctl+0x18f0/0x258c [...] Allocated by task 743: __kmalloc_cache_noprof+0x110/0x270 binder_new_node+0x50/0x700 binder_transaction+0x413c/0x6da8 binder_thread_write+0x978/0x3260 binder_ioctl+0x18f0/0x258c [...] Freed by task 745: kfree+0xbc/0x208 binder_thread_read+0x1c5c/0x37d4 binder_ioctl+0x16d8/0x258c [...] ================================================================== To avoid this issue, let's check that the raw data copy is within the boundaries of the data section. Fixes: 6d98eb95b450 ("binder: avoid potential data leakage when copying txn") Cc: Todd Kjos Cc: stable@vger.kernel.org Signed-off-by: Carlos Llamas Link: https://lore.kernel.org/r/20240822182353.2129600-1-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman

binder: fix hang of unregistered readers

2024-08-03T06:49:37Z

commit 31643d84b8c3d9c846aa0e20bc033e46c68c7e7d upstream. With the introduction of binder_available_for_proc_work_ilocked() in commit 1b77e9dcc3da ("ANDROID: binder: remove proc waitqueue") a binder thread can only "wait_for_proc_work" after its thread->looper has been marked as BINDER_LOOPER_STATE_{ENTERED|REGISTERED}. This means an unregistered reader risks waiting indefinitely for work since it never gets added to the proc->waiting_threads. If there are no further references to its waitqueue either the task will hang. The same applies to readers using the (e)poll interface. I couldn't find the rationale behind this restriction. So this patch restores the previous behavior of allowing unregistered threads to "wait_for_proc_work". Note that an error message for this scenario, which had previously become unreachable, is now re-enabled. Fixes: 1b77e9dcc3da ("ANDROID: binder: remove proc waitqueue") Cc: stable@vger.kernel.org Cc: Martijn Coenen Cc: Arve Hjønnevåg Signed-off-by: Carlos Llamas Link: https://lore.kernel.org/r/20240711201452.2017543-1-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman

binder: fix max_thread type inconsistency

2024-05-25T14:21:34Z

commit 42316941335644a98335f209daafa4c122f28983 upstream. The type defined for the BINDER_SET_MAX_THREADS ioctl was changed from size_t to __u32 in order to avoid incompatibility issues between 32 and 64-bit kernels. However, the internal types used to copy from user and store the value were never updated. Use u32 to fix the inconsistency. Fixes: a9350fc859ae ("staging: android: binder: fix BINDER_SET_MAX_THREADS declaration") Reported-by: Arve Hjønnevåg Cc: stable@vger.kernel.org Signed-off-by: Carlos Llamas Reviewed-by: Alice Ryhl Link: https://lore.kernel.org/r/20240421173750.3117808-1-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman

binder: check offset alignment in binder_get_object()

2024-04-27T15:07:13Z

commit aaef73821a3b0194a01bd23ca77774f704a04d40 upstream. Commit 6d98eb95b450 ("binder: avoid potential data leakage when copying txn") introduced changes to how binder objects are copied. In doing so, it unintentionally removed an offset alignment check done through calls to binder_alloc_copy_from_buffer() -> check_buffer(). These calls were replaced in binder_get_object() with copy_from_user(), so now an explicit offset alignment check is needed here. This avoids later complications when unwinding the objects gets harder. It is worth noting this check existed prior to commit 7a67a39320df ("binder: add function to copy binder object from buffer"), likely removed due to redundancy at the time. Fixes: 6d98eb95b450 ("binder: avoid potential data leakage when copying txn") Cc: stable@vger.kernel.org Signed-off-by: Carlos Llamas Acked-by: Todd Kjos Link: https://lore.kernel.org/r/20240330190115.1877819-1-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman

binder: signal epoll threads of self-work

2024-02-23T08:12:39Z

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: fix race between mmput() and do_exit()

2024-01-25T23:27:39Z

commit 9a9ab0d963621d9d12199df9817e66982582d5a5 upstream. Task A calls binder_update_page_range() to allocate and insert pages on a remote address space from Task B. For this, Task A pins the remote mm via mmget_not_zero() first. This can race with Task B do_exit() and the final mmput() refcount decrement will come from Task A. Task A | Task B ------------------+------------------ mmget_not_zero() | | do_exit() | exit_mm() | mmput() mmput() | exit_mmap() | remove_vma() | fput() | In this case, the work of ____fput() from Task B is queued up in Task A as TWA_RESUME. So in theory, Task A returns to userspace and the cleanup work gets executed. However, Task A instead sleep, waiting for a reply from Task B that never comes (it's dead). This means the binder_deferred_release() is blocked until an unrelated binder event forces Task A to go back to userspace. All the associated death notifications will also be delayed until then. In order to fix this use mmput_async() that will schedule the work in the corresponding mm->async_put_work WQ instead of Task A. Fixes: 457b9a6f09f0 ("Staging: android: add binder driver") Reviewed-by: Alice Ryhl Signed-off-by: Carlos Llamas Link: https://lore.kernel.org/r/20231201172212.1813387-4-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman

binder: fix unused alloc->free_async_space

2024-01-25T23:27:39Z

commit c6d05e0762ab276102246d24affd1e116a46aa0c upstream. Each transaction is associated with a 'struct binder_buffer' that stores the metadata about its buffer area. Since commit 74310e06be4d ("android: binder: Move buffer out of area shared with user space") this struct is no longer embedded within the buffer itself but is instead allocated on the heap to prevent userspace access to this driver-exclusive info. Unfortunately, the space of this struct is still being accounted for in the total buffer size calculation, specifically for async transactions. This results in an additional 104 bytes added to every async buffer request, and this area is never used. This wasted space can be substantial. If we consider the maximum mmap buffer space of SZ_4M, the driver will reserve half of it for async transactions, or 0x200000. This area should, in theory, accommodate up to 262,144 buffers of the minimum 8-byte size. However, after adding the extra 'sizeof(struct binder_buffer)', the total number of buffers drops to only 18,724, which is a sad 7.14% of the actual capacity. This patch fixes the buffer size calculation to enable the utilization of the entire async buffer space. This is expected to reduce the number of -ENOSPC errors that are seen on the field. Fixes: 74310e06be4d ("android: binder: Move buffer out of area shared with user space") Signed-off-by: Carlos Llamas Reviewed-by: Alice Ryhl Link: https://lore.kernel.org/r/20231201172212.1813387-6-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman

binder: fix async space check for 0-sized buffers

2024-01-25T23:27:39Z

commit 3091c21d3e9322428691ce0b7a0cfa9c0b239eeb upstream. Move the padding of 0-sized buffers to an earlier stage to account for this round up during the alloc->free_async_space check. Fixes: 74310e06be4d ("android: binder: Move buffer out of area shared with user space") Reviewed-by: Alice Ryhl Signed-off-by: Carlos Llamas Link: https://lore.kernel.org/r/20231201172212.1813387-5-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman

binder: fix comment on binder_alloc_new_buf() return value

2024-01-20T10:50:10Z

commit e1090371e02b601cbfcea175c2a6cc7c955fa830 upstream. Update the comments of binder_alloc_new_buf() to reflect that the return value of the function is now ERR_PTR(-errno) on failure. No functional changes in this patch. Cc: stable@vger.kernel.org Fixes: 57ada2fb2250 ("binder: add log information for binder transaction failures") Reviewed-by: Alice Ryhl Signed-off-by: Carlos Llamas Link: https://lore.kernel.org/r/20231201172212.1813387-8-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman

binder: fix trivial typo of binder_free_buf_locked()

2024-01-20T10:50:10Z

commit 122a3c1cb0ff304c2b8934584fcfea4edb2fe5e3 upstream. Fix minor misspelling of the function in the comment section. No functional changes in this patch. Cc: stable@vger.kernel.org Fixes: 0f966cba95c7 ("binder: add flag to clear buffer on txn complete") Reviewed-by: Alice Ryhl Signed-off-by: Carlos Llamas Link: https://lore.kernel.org/r/20231201172212.1813387-7-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman