CVE-2023-52438

binder: fix use-after-free in shinker's callback

HIGH

7.8

CVSS Score

Published: February 20, 2024 at 06:34 PM UTC

Updated: August 5, 2026 at 09:24 AM UTC

1 product affected across 1 vendorLinux Kernel

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Severity

HIGH7.8

Exploit prediction

EPSS 0.3%

SSVC

No known exploit

Description

In the Linux kernel, the following vulnerability has been resolved: binder: fix use-after-free in shinker's callback The mmap read lock is used during the shrinker's callback, which means that using alloc->vma pointer isn't safe as it can race with munmap(). As of commit dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") the mmap lock is downgraded after the vma has been isolated. I was able to reproduce this issue by manually adding some delays and triggering page reclaiming through the shrinker's debug sysfs. The following KASAN report confirms the UAF: ================================================================== BUG: KASAN: slab-use-after-free in zap_page_range_single+0x470/0x4b8 Read of size 8 at addr ffff356ed50e50f0 by task bash/478 CPU: 1 PID: 478 Comm: bash Not tainted 6.6.0-rc5-00055-g1c8b86a3799f-dirty #70 Hardware name: linux,dummy-virt (DT) Call trace: zap_page_range_single+0x470/0x4b8 binder_alloc_free_page+0x608/0xadc __list_lru_walk_one+0x130/0x3b0 list_lru_walk_node+0xc4/0x22c binder_shrink_scan+0x108/0x1dc shrinker_debugfs_scan_write+0x2b4/0x500 full_proxy_write+0xd4/0x140 vfs_write+0x1ac/0x758 ksys_write+0xf0/0x1dc __arm64_sys_write+0x6c/0x9c Allocated by task 492: kmem_cache_alloc+0x130/0x368 vm_area_alloc+0x2c/0x190 mmap_region+0x258/0x18bc do_mmap+0x694/0xa60 vm_mmap_pgoff+0x170/0x29c ksys_mmap_pgoff+0x290/0x3a0 __arm64_sys_mmap+0xcc/0x144 Freed by task 491: kmem_cache_free+0x17c/0x3c8 vm_area_free_rcu_cb+0x74/0x98 rcu_core+0xa38/0x26d4 rcu_core_si+0x10/0x1c __do_softirq+0x2fc/0xd24 Last potentially related work creation: __call_rcu_common.constprop.0+0x6c/0xba0 call_rcu+0x10/0x1c vm_area_free+0x18/0x24 remove_vma+0xe4/0x118 do_vmi_align_munmap.isra.0+0x718/0xb5c do_vmi_munmap+0xdc/0x1fc __vm_munmap+0x10c/0x278 __arm64_sys_munmap+0x58/0x7c Fix this issue by performing instead a vma_lookup() which will fail to find the vma that was isolated before the mmap lock downgrade. Note that this option has better performance than upgrading to a mmap write lock which would increase contention. Plus, mmap_write_trylock() has been recently removed anyway.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Linux Kernel · Linux

95%

4.20 ≤ v < 5.10.2094.20 ≤ v < 5.15.1484.20 ≤ v < 5.4.2684.20 ≤ v < 6.1.744.20 ≤ v < 6.6.134.20 ≤ v < 6.7.14.20 ≤ v < 6.84.20.0 ≤ v < 5.4.2685.11.0 ≤ v < 5.15.1485.16.0 ≤ v < 6.1.745.5.0 ≤ v < 5.10.2096.2.0 ≤ v < 6.6.136.7.0 ≤ v < 6.7.14.20dd2283f2605e3b3e9c61bcae844b34f2afa4813f

Vendor states this is fixed in 3f489c2067c5824528212b0fc18b28d51332d906 (fixed)

Vendor states this is fixed in 8ad4d580e8aff8de2a4d57c5930fcc29f1ffd4a6 (fixed)

Vendor states this is fixed in 9fa04c93f24138747807fe75b5591bb680098f56 (fixed)

Vendor states this is fixed in a49087ab93508b60d9b8add91707a22dda832869 (fixed)

Vendor states this is fixed in a53e15e592b4dcc91c3a3b8514e484a0bdbc53a3 (fixed)

Vendor states this is fixed in c8c1158ffb007197f31f9d9170cf13e4f34cbb5c (fixed)

Vendor states this is fixed in e074686e993ff1be5f21b085a3b1b4275ccd5727 (fixed)

Vendor states this is fixed in 4.20 (unaffected)

Vendor states this is fixed in 5.10.209 (unaffected)

Vendor states this is fixed in 5.15.148 (unaffected)

Vendor states this is fixed in 5.4.268 (unaffected)

Vendor states this is fixed in 6.1.74 (unaffected)