Vulnerability Details CVE-2024-56555
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 5.5%
CVSS Severity
CVSS v3 Score 7.1
Products affected by CVE-2024-56555
-
cpe:2.3:o:linux:linux_kernel:6.12
-
cpe:2.3:o:linux:linux_kernel:6.12.1
-
cpe:2.3:o:linux:linux_kernel:6.12.2
-
cpe:2.3:o:linux:linux_kernel:6.12.3