Description
In the Linux kernel, the following vulnerability has been resolved:
powerpc/kasan: Fix early region not updated correctly
The shadow's page table is not updated when PTE_RPN_SHIFT is 24
and PAGE_SHIFT is 12. It not only causes false positives but
also false negative as shown the following text.
Fix it by bringing the logic of kasan_early_shadow_page_entry here.
1. False Positive:
==================================================================
BUG: KASAN: vmalloc-out-of-bounds in pcpu_alloc+0x508/0xa50
Write of size 16 at addr f57f3be0 by task swapper/0/1
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.15.0-12267-gdebe436e77c7 #1
Call Trace:
[c80d1c20] [c07fe7b8] dump_stack_lvl+0x4c/0x6c (unreliable)
[c80d1c40] [c02ff668] print_address_description.constprop.0+0x88/0x300
[c80d1c70] [c02ff45c] kasan_report+0x1ec/0x200
[c80d1cb0] [c0300b20] kasan_check_range+0x160/0x2f0
[c80d1cc0] [c03018a4] memset+0x34/0x90
[c80d1ce0] [c0280108] pcpu_alloc+0x508/0xa50
[c80d1d40] [c02fd7bc] __kmem_cache_create+0xfc/0x570
[c80d1d70] [c0283d64] kmem_cache_create_usercopy+0x274/0x3e0
[c80d1db0] [c2036580] init_sd+0xc4/0x1d0
[c80d1de0] [c00044a0] do_one_initcall+0xc0/0x33c
[c80d1eb0] [c2001624] kernel_init_freeable+0x2c8/0x384
[c80d1ef0] [c0004b14] kernel_init+0x24/0x170
[c80d1f10] [c001b26c] ret_from_kernel_thread+0x5c/0x64
Memory state around the buggy address:
f57f3a80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
f57f3b00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>f57f3b80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
^
f57f3c00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
f57f3c80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================
2. False Negative (with KASAN tests):
==================================================================
Before fix:
ok 45 - kmalloc_double_kzfree
# vmalloc_oob: EXPECTATION FAILED at lib/test_kasan.c:1039
KASAN failure expected in "((volatile char *)area)[3100]", but none occurred
not ok 46 - vmalloc_oob
not ok 1 - kasan
==================================================================
After fix:
ok 1 - kasan
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 5.3.6 – < 5.4, 5.4 | 5.4 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 5.17.3-1 | — |
| Debian 13 | linux | 5.17.3-1 | — |
| Debian 12 | linux | 5.17.3-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | linux-raspi-realtime | No fix yet | — |
| Ubuntu 22.04 LTS | linux +1 | 5.15.0-37.39 | — |
| Ubuntu 22.04 LTS | linux-aws | 5.15.0-1011.14 | — |
| Ubuntu 22.04 LTS | linux-azure | 5.15.0-1010.12 | — |
| Ubuntu 22.04 LTS | linux-gcp | 5.15.0-1008.12 | — |
| Ubuntu 22.04 LTS | linux-gke | 5.15.0-1008.10 | — |
| Ubuntu 22.04 LTS | linux-ibm | 5.15.0-1007.8 | — |
| Ubuntu 22.04 LTS | linux-intel-iotg | 5.15.0-1008.11 | — |
| Ubuntu 22.04 LTS | linux-kvm | 5.15.0-1010.11 | — |
| Ubuntu 22.04 LTS | linux-oracle | 5.15.0-1009.12 | — |
| Ubuntu 22.04 LTS | linux-raspi | 5.15.0-1011.13 | — |
| Ubuntu 22.04 LTS | linux-riscv +32 | No fix yet | — |
| Ubuntu 20.04 LTS | linux | 5.4.0-117.132 | — |
| Ubuntu 20.04 LTS | linux-aws +1 | 5.4.0-1078.84 | — |
| Ubuntu 20.04 LTS | linux-azure | 5.4.0-1083.87 | — |
| Ubuntu 20.04 LTS | linux-azure-5.15 | 5.15.0-1008.9~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-bluefield | 5.4.0-1040.44 | — |
| Ubuntu 20.04 LTS | linux-gke +28 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-hwe-5.15 | 5.15.0-41.44~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-ibm | 5.4.0-1026.29 | — |
| Ubuntu 20.04 LTS | linux-intel-iotg-5.15 | 5.15.0-1008.11~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-iot | 5.4.0-1004.6 | — |
| Ubuntu 20.04 LTS | linux-kvm | 5.4.0-1068.72 | — |
| Ubuntu 20.04 LTS | linux-lowlatency-hwe-5.15 | 5.15.0-42.45~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-oracle | 5.4.0-1076.83 | — |
| Ubuntu 20.04 LTS | linux-raspi | 5.4.0-1065.75 | — |
| Ubuntu 18.04 LTS | linux-aws-5.4 +1 | 5.4.0-1078.84~18.04.1 | — |
| Ubuntu 18.04 LTS | linux-azure-5.4 | 5.4.0-1083.87~18.04.1 | — |
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-hwe-5.4 | 5.4.0-117.132~18.04.1 | — |
| Ubuntu 18.04 LTS | linux-ibm-5.4 | 5.4.0-1028.32~18.04.1 | — |
| Ubuntu 18.04 LTS | linux-oracle-5.4 | 5.4.0-1076.83~18.04.1 | — |
| Ubuntu 18.04 LTS | linux-raspi-5.4 | 5.4.0-1065.75~18.04.1 | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime | 5.15.0-1014.14 | — |
| Ubuntu Pro FIPS 20.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-aws-fips +1 | 5.4.0-1078.84+fips1 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-azure-fips | 5.4.0-1083.87+fips1 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-fips | 5.4.0-1054.61 | — |
References
- https://git.kernel.org/stable/c/7f19245c3647afea8c7c41f795506ef70f64b9f2
- https://git.kernel.org/stable/c/f39a3309393a4a484532f6ba745c6acbcfe06115
- https://git.kernel.org/stable/c/5a3d8f3192a409893c57808cc935e16484df1068
- https://git.kernel.org/stable/c/de56beace6648065d404cd9835aa7d30e3df519d
- https://git.kernel.org/stable/c/e3d157a4b4f4e0268c98be5b7013bf4b31234bb6
- https://git.kernel.org/stable/c/dd75080aa8409ce10d50fb58981c6b59bf8707d3