Linux Kernel up to 6.6.2 arm64 __cpu_setup denial of service

Summaryinfo

A vulnerability has been found in Linux Kernel up to 5.10.201/5.15.139/6.1.63/6.5.12/6.6.2 and classified as problematic. Impacted is the function __cpu_setup of the component arm64. The manipulation leads to denial of service. This vulnerability is uniquely identified as CVE-2023-52750. No exploit exists. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Linux Kernel up to 5.10.201/5.15.139/6.1.63/6.5.12/6.6.2. This issue affects the function __cpu_setup of the component arm64. The manipulation with an unknown input leads to a denial of service vulnerability. Using CWE to declare the problem leads to CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. Impacted is availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: arm64: Restrict CPU_BIG_ENDIAN to GNU as or LLVM IAS 15.x or newer Prior to LLVM 15.0.0, LLVM's integrated assembler would incorrectly byte-swap NOP when compiling for big-endian, and the resulting series of bytes happened to match the encoding of FNMADD S21, S30, S0, S0. This went unnoticed until commit: 34f66c4c4d5518c1 ("arm64: Use a positive cpucap for FP/SIMD") Prior to that commit, the kernel would always enable the use of FPSIMD early in boot when __cpu_setup() initialized CPACR_EL1, and so usage of FNMADD within the kernel was not detected, but could result in the corruption of user or kernel FPSIMD state. After that commit, the instructions happen to trap during boot prior to FPSIMD being detected and enabled, e.g. | Unhandled 64-bit el1h sync exception on CPU0, ESR 0x000000001fe00000 -- ASIMD | CPU: 0 PID: 0 Comm: swapper Not tainted 6.6.0-rc3-00013-g34f66c4c4d55 #1 | Hardware name: linux,dummy-virt (DT) | pstate: 400000c9 (nZcv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) | pc : __pi_strcmp+0x1c/0x150 | lr : populate_properties+0xe4/0x254 | sp : ffffd014173d3ad0 | x29: ffffd014173d3af0 x28: fffffbfffddffcb8 x27: 0000000000000000 | x26: 0000000000000058 x25: fffffbfffddfe054 x24: 0000000000000008 | x23: fffffbfffddfe000 x22: fffffbfffddfe000 x21: fffffbfffddfe044 | x20: ffffd014173d3b70 x19: 0000000000000001 x18: 0000000000000005 | x17: 0000000000000010 x16: 0000000000000000 x15: 00000000413e7000 | x14: 0000000000000000 x13: 0000000000001bcc x12: 0000000000000000 | x11: 00000000d00dfeed x10: ffffd414193f2cd0 x9 : 0000000000000000 | x8 : 0101010101010101 x7 : ffffffffffffffc0 x6 : 0000000000000000 | x5 : 0000000000000000 x4 : 0101010101010101 x3 : 000000000000002a | x2 : 0000000000000001 x1 : ffffd014171f2988 x0 : fffffbfffddffcb8 | Kernel panic - not syncing: Unhandled exception | CPU: 0 PID: 0 Comm: swapper Not tainted 6.6.0-rc3-00013-g34f66c4c4d55 #1 | Hardware name: linux,dummy-virt (DT) | Call trace: | dump_backtrace+0xec/0x108 | show_stack+0x18/0x2c | dump_stack_lvl+0x50/0x68 | dump_stack+0x18/0x24 | panic+0x13c/0x340 | el1t_64_irq_handler+0x0/0x1c | el1_abort+0x0/0x5c | el1h_64_sync+0x64/0x68 | __pi_strcmp+0x1c/0x150 | unflatten_dt_nodes+0x1e8/0x2d8 | __unflatten_device_tree+0x5c/0x15c | unflatten_device_tree+0x38/0x50 | setup_arch+0x164/0x1e0 | start_kernel+0x64/0x38c | __primary_switched+0xbc/0xc4 Restrict CONFIG_CPU_BIG_ENDIAN to a known good assembler, which is either GNU as or LLVM's IAS 15.0.0 and newer, which contains the linked commit.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2023-52750. The exploitation is known to be difficult. Technical details are known, but no exploit is available.

Upgrading to version 5.10.202, 5.15.140, 6.1.64, 6.5.13 or 6.6.3 eliminates this vulnerability. Applying the patch d08a1e75253b/936c9c10efae/ef0224ee5399/bd31e534721a/69e619d2fd05/146a15b87335 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.10.201
• 5.15.139
• 6.1.0
• 6.1.1
• 6.1.2
• 6.1.3
• 6.1.4
• 6.1.5
• 6.1.6
• 6.1.7
• 6.1.8
• 6.1.9
• 6.1.10
• 6.1.11
• 6.1.12
• 6.1.13
• 6.1.14
• 6.1.15
• 6.1.16
• 6.1.17
• 6.1.18
• 6.1.19
• 6.1.20
• 6.1.21
• 6.1.22
• 6.1.23
• 6.1.24
• 6.1.25
• 6.1.26
• 6.1.27
• 6.1.28
• 6.1.29
• 6.1.30
• 6.1.31
• 6.1.32
• 6.1.33
• 6.1.34
• 6.1.35
• 6.1.36
• 6.1.37
• 6.1.38
• 6.1.39
• 6.1.40
• 6.1.41
• 6.1.42
• 6.1.43
• 6.1.44
• 6.1.45
• 6.1.46
• 6.1.47
• 6.1.48
• 6.1.49
• 6.1.50
• 6.1.51
• 6.1.52
• 6.1.53
• 6.1.54
• 6.1.55
• 6.1.56
• 6.1.57
• 6.1.58
• 6.1.59
• 6.1.60
• 6.1.61
• 6.1.62
• 6.1.63
• 6.5.0
• 6.5.1
• 6.5.2
• 6.5.3
• 6.5.4
• 6.5.5
• 6.5.6
• 6.5.7
• 6.5.8
• 6.5.9
• 6.5.10
• 6.5.11
• 6.5.12
• 6.6.0
• 6.6.1
• 6.6.2

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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