CVE-2021-47640
published 2025-02-26CVE-2021-47640: 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…
PriorityP338high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.26%
17.1th percentile
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
19 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | linux | < linux 5.17.3-1 (bookworm) | linux 5.17.3-1 (bookworm) |
| linux | linux | — | — |
| linux | linux | — | — |
| linux | linux | >= 5.3.6 < 5.4 | 5.4 |
| linux | linux | >= cbd18991e24fea2c31da3bb117c83e4a3538cd11 < 7f19245c3647afea8c7c41f795506ef70f64b9f2 | 7f19245c3647afea8c7c41f795506ef70f64b9f2 |
| linux | linux | >= cbd18991e24fea2c31da3bb117c83e4a3538cd11 < f39a3309393a4a484532f6ba745c6acbcfe06115 | f39a3309393a4a484532f6ba745c6acbcfe06115 |
| linux | linux | >= cbd18991e24fea2c31da3bb117c83e4a3538cd11 < 5a3d8f3192a409893c57808cc935e16484df1068 | 5a3d8f3192a409893c57808cc935e16484df1068 |
| linux | linux | >= cbd18991e24fea2c31da3bb117c83e4a3538cd11 < de56beace6648065d404cd9835aa7d30e3df519d | de56beace6648065d404cd9835aa7d30e3df519d |
| linux | linux | >= cbd18991e24fea2c31da3bb117c83e4a3538cd11 < e3d157a4b4f4e0268c98be5b7013bf4b31234bb6 | e3d157a4b4f4e0268c98be5b7013bf4b31234bb6 |
| linux | linux | >= cbd18991e24fea2c31da3bb117c83e4a3538cd11 < dd75080aa8409ce10d50fb58981c6b59bf8707d3 | dd75080aa8409ce10d50fb58981c6b59bf8707d3 |
| linux | linux_kernel | >= 0 < 5.10.113-1 | 5.10.113-1 |
| linux | linux_kernel | >= 0 < 5.17.3-1 | 5.17.3-1 |
| linux | linux_kernel | >= 0 < 5.17.3-1 | 5.17.3-1 |
| linux | linux_kernel | >= 0 < 5.17.3-1 | 5.17.3-1 |
| linux | linux_kernel | >= 5.11 < 5.15.33 | 5.15.33 |
| linux | linux_kernel | >= 5.16 < 5.16.19 | 5.16.19 |
| linux | linux_kernel | >= 5.17 < 5.17.2 | 5.17.2 |
| linux | linux_kernel | >= 5.4 < 5.4.189 | 5.4.189 |
| linux | linux_kernel | >= 5.5 < 5.10.110 | 5.10.110 |
CVSS provenance
nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
osv7.8HIGH
vendor_debian7.8HIGH
vendor_redhat7.8HIGH
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GHSA
GHSA-wv3g-qf6c-pg8j: In the Linux kernel, the following vulnerability has been resolved:
powerpc/kasan: Fix early region not updated correctly
The shadow's page table is
ghsa_unreviewed·2025-03-18
CVE-2021-47640 [HIGH] CWE-787 GHSA-wv3g-qf6c-pg8j: In the Linux kernel, the following vulnerability has been resolved:
powerpc/kasan: Fix early region not updated correctly
The shadow's page table is
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_ra
OSV
CVE-2021-47640: In the Linux kernel, the following vulnerability has been resolved: powerpc/kasan: Fix early region not updated correctly The shadow's page table is n
osv·2025-02-26·CVSS 7.8
CVE-2021-47640 [HIGH] CVE-2021-47640: In the Linux kernel, the following vulnerability has been resolved: powerpc/kasan: Fix early region not updated correctly The shadow's page table is n
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]
Red Hat
kernel: powerpc/kasan: Fix early region not updated correctly
vendor_redhat·2025-02-26·CVSS 7.8
CVE-2021-47640 [HIGH] CWE-787 kernel: powerpc/kasan: Fix early region not updated correctly
kernel: powerpc/kasan: Fix early region not updated correctly
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] kas
Debian
CVE-2021-47640: linux - In the Linux kernel, the following vulnerability has been resolved: powerpc/kas...
vendor_debian·2021·CVSS 7.8
CVE-2021-47640 [HIGH] CVE-2021-47640: linux - In the Linux kernel, the following vulnerability has been resolved: powerpc/kas...
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]
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
https://git.kernel.org/stable/c/5a3d8f3192a409893c57808cc935e16484df1068https://git.kernel.org/stable/c/7f19245c3647afea8c7c41f795506ef70f64b9f2https://git.kernel.org/stable/c/dd75080aa8409ce10d50fb58981c6b59bf8707d3https://git.kernel.org/stable/c/de56beace6648065d404cd9835aa7d30e3df519dhttps://git.kernel.org/stable/c/e3d157a4b4f4e0268c98be5b7013bf4b31234bb6https://git.kernel.org/stable/c/f39a3309393a4a484532f6ba745c6acbcfe06115
2025-02-26
Published