First published: Tue Feb 20 2024(Updated: )
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.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Software | Affected Version | How to fix |
---|---|---|
Linux Linux kernel | >=4.20.0<5.4.268 | |
Linux Linux kernel | >=5.5.0<5.10.209 | |
Linux Linux kernel | >=5.11.0<5.15.148 | |
Linux Linux kernel | >=5.16.0<6.1.74 | |
Linux Linux kernel | >=6.2.0<6.6.13 | |
Linux Linux kernel | >=6.7.0<6.7.1 | |
ubuntu/linux | <5.4.0-176.196 | 5.4.0-176.196 |
ubuntu/linux | <5.15.0-102.112 | 5.15.0-102.112 |
ubuntu/linux | <6.8~ | 6.8~ |
ubuntu/linux-aws | <5.4.0-1122.132 | 5.4.0-1122.132 |
ubuntu/linux-aws | <5.15.0-1057.63 | 5.15.0-1057.63 |
ubuntu/linux-aws | <6.8~ | 6.8~ |
ubuntu/linux-aws-5.15 | <5.15.0-1057.63~20.04.1 | 5.15.0-1057.63~20.04.1 |
ubuntu/linux-aws-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-aws-5.4 | <6.8~ | 6.8~ |
ubuntu/linux-aws-6.5 | <6.8~ | 6.8~ |
ubuntu/linux-aws-fips | <6.8~ | 6.8~ |
ubuntu/linux-aws-hwe | <6.8~ | 6.8~ |
ubuntu/linux-azure | <5.4.0-1127.134 | 5.4.0-1127.134 |
ubuntu/linux-azure | <5.15.0-1060.69 | 5.15.0-1060.69 |
ubuntu/linux-azure | <6.8~ | 6.8~ |
ubuntu/linux-azure-4.15 | <6.8~ | 6.8~ |
ubuntu/linux-azure-5.15 | <5.15.0-1060.69~20.04.1 | 5.15.0-1060.69~20.04.1 |
ubuntu/linux-azure-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-azure-5.4 | <6.8~ | 6.8~ |
ubuntu/linux-azure-6.5 | <6.8~ | 6.8~ |
ubuntu/linux-azure-fde | <5.15.0-1060.69.1 | 5.15.0-1060.69.1 |
ubuntu/linux-azure-fde | <6.8~ | 6.8~ |
ubuntu/linux-azure-fde-5.15 | <5.15.0-1060.69~20.04.1.1 | 5.15.0-1060.69~20.04.1.1 |
ubuntu/linux-azure-fde-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-azure-fips | <6.8~ | 6.8~ |
ubuntu/linux-bluefield | <5.4.0-1082.89 | 5.4.0-1082.89 |
ubuntu/linux-bluefield | <6.8~ | 6.8~ |
ubuntu/linux-fips | <6.8~ | 6.8~ |
ubuntu/linux-gcp | <5.4.0-1126.135 | 5.4.0-1126.135 |
ubuntu/linux-gcp | <5.15.0-1055.63 | 5.15.0-1055.63 |
ubuntu/linux-gcp | <6.8~ | 6.8~ |
ubuntu/linux-gcp-4.15 | <6.8~ | 6.8~ |
ubuntu/linux-gcp-5.15 | <5.15.0-1055.63~20.04.1 | 5.15.0-1055.63~20.04.1 |
ubuntu/linux-gcp-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-gcp-5.4 | <6.8~ | 6.8~ |
ubuntu/linux-gcp-6.5 | <6.8~ | 6.8~ |
ubuntu/linux-gcp-fips | <6.8~ | 6.8~ |
ubuntu/linux-gke | <5.15.0-1054.59 | 5.15.0-1054.59 |
ubuntu/linux-gke | <6.8~ | 6.8~ |
ubuntu/linux-gkeop | <5.4.0-1089.93 | 5.4.0-1089.93 |
ubuntu/linux-gkeop | <5.15.0-1040.46 | 5.15.0-1040.46 |
ubuntu/linux-gkeop | <6.8~ | 6.8~ |
ubuntu/linux-gkeop-5.15 | <5.15.0-1040.46~20.04.1 | 5.15.0-1040.46~20.04.1 |
ubuntu/linux-gkeop-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-hwe | <6.8~ | 6.8~ |
ubuntu/linux-hwe-5.15 | <5.15.0-102.112~20.04.1 | 5.15.0-102.112~20.04.1 |
ubuntu/linux-hwe-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-hwe-5.4 | <6.8~ | 6.8~ |
ubuntu/linux-hwe-6.5 | <6.8~ | 6.8~ |
ubuntu/linux-ibm | <5.4.0-1069.74 | 5.4.0-1069.74 |
ubuntu/linux-ibm | <5.15.0-1050.53 | 5.15.0-1050.53 |
ubuntu/linux-ibm | <6.8~ | 6.8~ |
ubuntu/linux-ibm-5.15 | <5.15.0-1050.53~20.04.1 | 5.15.0-1050.53~20.04.1 |
ubuntu/linux-ibm-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-ibm-5.4 | <6.8~ | 6.8~ |
ubuntu/linux-intel | <6.8~ | 6.8~ |
ubuntu/linux-intel-iot-realtime | <6.8~ | 6.8~ |
ubuntu/linux-intel-iotg | <5.15.0-1052.58 | 5.15.0-1052.58 |
ubuntu/linux-intel-iotg | <6.8~ | 6.8~ |
ubuntu/linux-intel-iotg-5.15 | <5.15.0-1052.58~20.04.1 | 5.15.0-1052.58~20.04.1 |
ubuntu/linux-intel-iotg-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-iot | <5.4.0-1034.35 | 5.4.0-1034.35 |
ubuntu/linux-iot | <6.8~ | 6.8~ |
ubuntu/linux-kvm | <5.4.0-1110.117 | 5.4.0-1110.117 |
ubuntu/linux-kvm | <5.15.0-1054.59 | 5.15.0-1054.59 |
ubuntu/linux-kvm | <6.8~ | 6.8~ |
ubuntu/linux-laptop | <6.8~ | 6.8~ |
ubuntu/linux-lowlatency | <5.15.0-102.112 | 5.15.0-102.112 |
ubuntu/linux-lowlatency | <6.8~ | 6.8~ |
ubuntu/linux-lowlatency-hwe-5.15 | <5.15.0-102.112~20.04.1 | 5.15.0-102.112~20.04.1 |
ubuntu/linux-lowlatency-hwe-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-lowlatency-hwe-6.5 | <6.8~ | 6.8~ |
ubuntu/linux-lowlatency-hwe-6.8 | <6.8~ | 6.8~ |
ubuntu/linux-lts-xenial | <6.8~ | 6.8~ |
ubuntu/linux-nvidia | <5.15.0-1048.48 | 5.15.0-1048.48 |
ubuntu/linux-nvidia | <6.8~ | 6.8~ |
ubuntu/linux-nvidia-6.5 | <6.5.0-1014.14 | 6.5.0-1014.14 |
ubuntu/linux-nvidia-6.5 | <6.8~ | 6.8~ |
ubuntu/linux-nvidia-6.8 | <6.8~ | 6.8~ |
ubuntu/linux-nvidia-lowlatency | <6.8~ | 6.8~ |
ubuntu/linux-oem-6.1 | <6.1.0-1035.35 | 6.1.0-1035.35 |
ubuntu/linux-oem-6.5 | <6.8~ | 6.8~ |
ubuntu/linux-oem-6.8 | <6.8~ | 6.8~ |
ubuntu/linux-oracle | <5.4.0-1121.130 | 5.4.0-1121.130 |
ubuntu/linux-oracle | <5.15.0-1055.61 | 5.15.0-1055.61 |
ubuntu/linux-oracle | <6.8~ | 6.8~ |
ubuntu/linux-oracle-5.15 | <5.15.0-1055.61~20.04.1 | 5.15.0-1055.61~20.04.1 |
ubuntu/linux-oracle-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-oracle-5.4 | <6.8~ | 6.8~ |
ubuntu/linux-oracle-6.5 | <6.8~ | 6.8~ |
ubuntu/linux-raspi | <5.4.0-1106.118 | 5.4.0-1106.118 |
ubuntu/linux-raspi | <5.15.0-1050.53 | 5.15.0-1050.53 |
ubuntu/linux-raspi | <6.8~ | 6.8~ |
ubuntu/linux-raspi-5.4 | <6.8~ | 6.8~ |
ubuntu/linux-raspi-realtime | <6.8~ | 6.8~ |
ubuntu/linux-realtime | <6.8~ | 6.8~ |
ubuntu/linux-riscv | <6.8~ | 6.8~ |
ubuntu/linux-riscv-5.15 | <5.15.0-1053.57~20.04.1 | 5.15.0-1053.57~20.04.1 |
ubuntu/linux-riscv-5.15 | <6.8~ | 6.8~ |
ubuntu/linux-riscv-6.5 | <6.8~ | 6.8~ |
ubuntu/linux-riscv-6.8 | <6.8~ | 6.8~ |
ubuntu/linux-starfive | <6.8~ | 6.8~ |
ubuntu/linux-starfive-6.5 | <6.8~ | 6.8~ |
ubuntu/linux-xilinx-zynqmp | <5.4.0-1041.45 | 5.4.0-1041.45 |
ubuntu/linux-xilinx-zynqmp | <5.15.0-1030.34 | 5.15.0-1030.34 |
ubuntu/linux-xilinx-zynqmp | <6.8~ | 6.8~ |
debian/linux | 5.10.223-1 6.1.106-3 6.1.99-1 6.10.6-1 6.10.7-1 |
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(Appears in the following advisories)