Bug 2334506 (CVE-2024-56555) - CVE-2024-56555 kernel: binder: fix OOB in binder_add_freeze_work()
Summary: CVE-2024-56555 kernel: binder: fix OOB in binder_add_freeze_work()
Keywords:
Status: NEW
Alias: CVE-2024-56555
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2024-12-27 15:06 UTC by OSIDB Bzimport
Modified: 2025-03-11 14:06 UTC (History)
4 users (show)

Fixed In Version:
Clone Of:
Environment:
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Description OSIDB Bzimport 2024-12-27 15:06:29 UTC
In the Linux kernel, the following vulnerability has been resolved:

binder: fix OOB in binder_add_freeze_work()

In binder_add_freeze_work() we iterate over the proc->nodes with the
proc->inner_lock held. However, this lock is temporarily dropped to
acquire the node->lock first (lock nesting order). This can race with
binder_deferred_release() which removes the nodes from the proc->nodes
rbtree and adds them into binder_dead_nodes list. This leads to a broken
iteration in binder_add_freeze_work() as rb_next() will use data from
binder_dead_nodes, triggering an out-of-bounds access:

  ==================================================================
  BUG: KASAN: global-out-of-bounds in rb_next+0xfc/0x124
  Read of size 8 at addr ffffcb84285f7170 by task freeze/660

  CPU: 8 UID: 0 PID: 660 Comm: freeze Not tainted 6.11.0-07343-ga727812a8d45 #18
  Hardware name: linux,dummy-virt (DT)
  Call trace:
   rb_next+0xfc/0x124
   binder_add_freeze_work+0x344/0x534
   binder_ioctl+0x1e70/0x25ac
   __arm64_sys_ioctl+0x124/0x190

  The buggy address belongs to the variable:
   binder_dead_nodes+0x10/0x40
  [...]
  ==================================================================

This is possible because proc->nodes (rbtree) and binder_dead_nodes
(list) share entries in binder_node through a union:

	struct binder_node {
	[...]
		union {
			struct rb_node rb_node;
			struct hlist_node dead_node;
		};

Fix the race by checking that the proc is still alive. If not, simply
break out of the iteration.

Comment 1 Avinash Hanwate 2024-12-28 04:51:13 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024122711-CVE-2024-56555-6abc@gregkh/T


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