In the Linux kernel, the following vulnerability has been resolved:EOL][EOL]arm64: fix oops in concurrently setting insn_emulation sysctls[EOL][EOL]emulation_proc_handler() changes table->data for proc_dointvec_minmax[EOL]and can generate the following Oops if called concurrently with itself:[EOL][EOL] ( Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010[EOL) | Internal error: Oops: 96000006 #1] SMP[EOL] ( Call trace:[EOL) | update_insn_emulation_mode+0xc0/0x148EOL] ( emulation_proc_handler+0x64/0xb8[EOL) | proc_sys_call_handler+0x9c/0xf8EOL] ( proc_sys_write+0x18/0x20[EOL) | __vfs_write+0x20/0x48EOL] ( vfs_write+0xe4/0x1d0[EOL) | ksys_write+0x70/0xf8EOL] ( __arm64_sys_write+0x20/0x28[EOL) | el0_svc_common.constprop.0+0x7c/0x1c0EOL] ( el0_svc_handler+0x2c/0xa0[EOL) | el0_svc+0x8/0x200EOL][EOL]To fix this issue, keep the table->data as &insn->current_mode and[EOL]use container_of() to retrieve the insn pointer. Another mutex is[EOL]used to protect against the current_mode update but not for retrieving[EOL]insn_emulation as table->data is no longer changing. CREATE(Triage):(User=lchen-cn) [CVE-2022-50206 (https://nvd.nist.gov/vuln/detail/CVE-2022-50206)
