CVE-2024-46740 Information

Description

In the Linux kernel the following vulnerability has been resolved:

binder: fix UAF caused by offsets overwrite

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: linuxdummy-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.

Reference

https://git.kernel.org/stable/c/5a32bfd23022ffa7e152f273fa3fa29befb7d929 https://git.kernel.org/stable/c/3a8154bb4ab4a01390a3abf1e6afac296e037da4 https://git.kernel.org/stable/c/eef79854a04feac5b861f94d7b19cbbe79874117 https://git.kernel.org/stable/c/4f79e0b80dc69bd5eaaed70f0df1b558728b4e59 https://git.kernel.org/stable/c/1f33d9f1d9ac3f0129f8508925000900c2fe5bb0 https://git.kernel.org/stable/c/109e845c1184c9f786d41516348ba3efd9112792 https://git.kernel.org/stable/c/4df153652cc46545722879415937582028c18af5