CVE-2023-53699
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-10-22

Last updated on: 2025-10-22

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: riscv: move memblock_allow_resize() after linear mapping is ready The initial memblock metadata is accessed from kernel image mapping. The regions arrays need to "reallocated" from memblock and accessed through linear mapping to cover more memblock regions. So the resizing should not be allowed until linear mapping is ready. Note that there are memblock allocations when building linear mapping. This patch is similar to 24cc61d8cb5a ("arm64: memblock: don't permit memblock resizing until linear mapping is up"). In following log, many memblock regions are reserved before create_linear_mapping_page_table(). And then it triggered reallocation of memblock.reserved.regions and memcpy the old array in kernel image mapping to the new array in linear mapping which caused a page fault. [ 0.000000] memblock_reserve: [0x00000000bf01f000-0x00000000bf01ffff] early_init_fdt_scan_reserved_mem+0x28c/0x2c6 [ 0.000000] memblock_reserve: [0x00000000bf021000-0x00000000bf021fff] early_init_fdt_scan_reserved_mem+0x28c/0x2c6 [ 0.000000] memblock_reserve: [0x00000000bf023000-0x00000000bf023fff] early_init_fdt_scan_reserved_mem+0x28c/0x2c6 [ 0.000000] memblock_reserve: [0x00000000bf025000-0x00000000bf025fff] early_init_fdt_scan_reserved_mem+0x28c/0x2c6 [ 0.000000] memblock_reserve: [0x00000000bf027000-0x00000000bf027fff] early_init_fdt_scan_reserved_mem+0x28c/0x2c6 [ 0.000000] memblock_reserve: [0x00000000bf029000-0x00000000bf029fff] early_init_fdt_scan_reserved_mem+0x28c/0x2c6 [ 0.000000] memblock_reserve: [0x00000000bf02b000-0x00000000bf02bfff] early_init_fdt_scan_reserved_mem+0x28c/0x2c6 [ 0.000000] memblock_reserve: [0x00000000bf02d000-0x00000000bf02dfff] early_init_fdt_scan_reserved_mem+0x28c/0x2c6 [ 0.000000] memblock_reserve: [0x00000000bf02f000-0x00000000bf02ffff] early_init_fdt_scan_reserved_mem+0x28c/0x2c6 [ 0.000000] memblock_reserve: [0x00000000bf030000-0x00000000bf030fff] early_init_fdt_scan_reserved_mem+0x28c/0x2c6 [ 0.000000] OF: reserved mem: 0x0000000080000000..0x000000008007ffff (512 KiB) map non-reusable mmode_resv0@80000000 [ 0.000000] memblock_reserve: [0x00000000bf000000-0x00000000bf001fed] paging_init+0x19a/0x5ae [ 0.000000] memblock_phys_alloc_range: 4096 bytes align=0x1000 from=0x0000000000000000 max_addr=0x0000000000000000 alloc_pmd_fixmap+0x14/0x1c [ 0.000000] memblock_reserve: [0x000000017ffff000-0x000000017fffffff] memblock_alloc_range_nid+0xb8/0x128 [ 0.000000] memblock: reserved is doubled to 256 at [0x000000017fffd000-0x000000017fffe7ff] [ 0.000000] Unable to handle kernel paging request at virtual address ff600000ffffd000 [ 0.000000] Oops [#1] [ 0.000000] Modules linked in: [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 6.4.0-rc1-00011-g99a670b2069c #66 [ 0.000000] Hardware name: riscv-virtio,qemu (DT) [ 0.000000] epc : __memcpy+0x60/0xf8 [ 0.000000] ra : memblock_double_array+0x192/0x248 [ 0.000000] epc : ffffffff8081d214 ra : ffffffff80a3dfc0 sp : ffffffff81403bd0 [ 0.000000] gp : ffffffff814fbb38 tp : ffffffff8140dac0 t0 : 0000000001600000 [ 0.000000] t1 : 0000000000000000 t2 : 000000008f001000 s0 : ffffffff81403c60 [ 0.000000] s1 : ffffffff80c0bc98 a0 : ff600000ffffd000 a1 : ffffffff80c0bcd8 [ 0.000000] a2 : 0000000000000c00 a3 : ffffffff80c0c8d8 a4 : 0000000080000000 [ 0.000000] a5 : 0000000000080000 a6 : 0000000000000000 a7 : 0000000080200000 [ 0.000000] s2 : ff600000ffffd000 s3 : 0000000000002000 s4 : 0000000000000c00 [ 0.000000] s5 : ffffffff80c0bc60 s6 : ffffffff80c0bcc8 s7 : 0000000000000000 [ 0.000000] s8 : ffffffff814fd0a8 s9 : 000000017fffe7ff s10: 0000000000000000 [ 0.000000] s11: 0000000000001000 t3 : 0000000000001000 t4 : 0000000000000000 [ 0.000000] t5 : 000000008f003000 t6 : ff600000ffffd000 [ 0.000000] status: 0000000200000100 badaddr: ff600000ffffd000 cause: 000000000000000f [ 0.000000] [<fff ---truncated---
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Meta Information
Published
2025-10-22
Last Modified
2025-10-22
Generated
2026-05-07
AI Q&A
2025-10-22
EPSS Evaluated
2026-05-05
NVD
EUVD
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel 6.4.0-rc1
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-UNKNOWN
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability in the Linux kernel's riscv architecture involves the improper timing of resizing memblock metadata arrays. The memblock metadata, which tracks reserved memory regions, is initially accessed through kernel image mapping. However, the arrays need to be reallocated and accessed through linear mapping to cover more regions. The vulnerability occurs because resizing was allowed before the linear mapping was ready, causing a page fault when the kernel tried to copy the old array to the new one. The fix moves the memblock_allow_resize() call to after the linear mapping is established, preventing this fault.


How can this vulnerability impact me? :

This vulnerability can cause the Linux kernel to crash with a page fault during early boot on riscv systems, potentially leading to system instability or failure to boot. This could impact system availability and reliability.


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