kernel_optimize_test/arch/s390/kernel/asm-offsets.c
Sven Schnelle 0b38b5e1d0 s390: prevent leaking kernel address in BEAR
When userspace executes a syscall or gets interrupted,
BEAR contains a kernel address when returning to userspace.
This make it pretty easy to figure out where the kernel is
mapped even with KASLR enabled. To fix this, add lpswe to
lowcore and always execute it there, so userspace sees only
the lowcore address of lpswe. For this we have to extend
both critical_cleanup and the SWITCH_ASYNC macro to also check
for lpswe addresses in lowcore.

Fixes: b2d24b97b2 ("s390/kernel: add support for kernel address space layout randomization (KASLR)")
Cc: <stable@vger.kernel.org> # v5.2+
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2020-03-10 15:16:25 +01:00

209 lines
9.2 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Generate definitions needed by assembly language modules.
* This code generates raw asm output which is post-processed to extract
* and format the required data.
*/
#define ASM_OFFSETS_C
#include <linux/kbuild.h>
#include <linux/kvm_host.h>
#include <linux/sched.h>
#include <linux/purgatory.h>
#include <asm/idle.h>
#include <asm/vdso.h>
#include <asm/pgtable.h>
#include <asm/gmap.h>
#include <asm/nmi.h>
#include <asm/stacktrace.h>
int main(void)
{
/* task struct offsets */
OFFSET(__TASK_stack, task_struct, stack);
OFFSET(__TASK_thread, task_struct, thread);
OFFSET(__TASK_pid, task_struct, pid);
BLANK();
/* thread struct offsets */
OFFSET(__THREAD_ksp, thread_struct, ksp);
OFFSET(__THREAD_sysc_table, thread_struct, sys_call_table);
OFFSET(__THREAD_last_break, thread_struct, last_break);
OFFSET(__THREAD_FPU_fpc, thread_struct, fpu.fpc);
OFFSET(__THREAD_FPU_regs, thread_struct, fpu.regs);
OFFSET(__THREAD_per_cause, thread_struct, per_event.cause);
OFFSET(__THREAD_per_address, thread_struct, per_event.address);
OFFSET(__THREAD_per_paid, thread_struct, per_event.paid);
OFFSET(__THREAD_trap_tdb, thread_struct, trap_tdb);
BLANK();
/* thread info offsets */
OFFSET(__TI_flags, task_struct, thread_info.flags);
BLANK();
/* pt_regs offsets */
OFFSET(__PT_ARGS, pt_regs, args);
OFFSET(__PT_PSW, pt_regs, psw);
OFFSET(__PT_GPRS, pt_regs, gprs);
OFFSET(__PT_ORIG_GPR2, pt_regs, orig_gpr2);
OFFSET(__PT_INT_CODE, pt_regs, int_code);
OFFSET(__PT_INT_PARM, pt_regs, int_parm);
OFFSET(__PT_INT_PARM_LONG, pt_regs, int_parm_long);
OFFSET(__PT_FLAGS, pt_regs, flags);
DEFINE(__PT_SIZE, sizeof(struct pt_regs));
BLANK();
/* stack_frame offsets */
OFFSET(__SF_BACKCHAIN, stack_frame, back_chain);
OFFSET(__SF_GPRS, stack_frame, gprs);
OFFSET(__SF_EMPTY, stack_frame, empty1);
OFFSET(__SF_SIE_CONTROL, stack_frame, empty1[0]);
OFFSET(__SF_SIE_SAVEAREA, stack_frame, empty1[1]);
OFFSET(__SF_SIE_REASON, stack_frame, empty1[2]);
OFFSET(__SF_SIE_FLAGS, stack_frame, empty1[3]);
BLANK();
/* timeval/timezone offsets for use by vdso */
OFFSET(__VDSO_UPD_COUNT, vdso_data, tb_update_count);
OFFSET(__VDSO_XTIME_STAMP, vdso_data, xtime_tod_stamp);
OFFSET(__VDSO_XTIME_SEC, vdso_data, xtime_clock_sec);
OFFSET(__VDSO_XTIME_NSEC, vdso_data, xtime_clock_nsec);
OFFSET(__VDSO_XTIME_CRS_SEC, vdso_data, xtime_coarse_sec);
OFFSET(__VDSO_XTIME_CRS_NSEC, vdso_data, xtime_coarse_nsec);
OFFSET(__VDSO_WTOM_SEC, vdso_data, wtom_clock_sec);
OFFSET(__VDSO_WTOM_NSEC, vdso_data, wtom_clock_nsec);
OFFSET(__VDSO_WTOM_CRS_SEC, vdso_data, wtom_coarse_sec);
OFFSET(__VDSO_WTOM_CRS_NSEC, vdso_data, wtom_coarse_nsec);
OFFSET(__VDSO_TIMEZONE, vdso_data, tz_minuteswest);
OFFSET(__VDSO_ECTG_OK, vdso_data, ectg_available);
OFFSET(__VDSO_TK_MULT, vdso_data, tk_mult);
OFFSET(__VDSO_TK_SHIFT, vdso_data, tk_shift);
OFFSET(__VDSO_TS_DIR, vdso_data, ts_dir);
OFFSET(__VDSO_TS_END, vdso_data, ts_end);
OFFSET(__VDSO_ECTG_BASE, vdso_per_cpu_data, ectg_timer_base);
OFFSET(__VDSO_ECTG_USER, vdso_per_cpu_data, ectg_user_time);
OFFSET(__VDSO_GETCPU_VAL, vdso_per_cpu_data, getcpu_val);
BLANK();
/* constants used by the vdso */
DEFINE(__CLOCK_REALTIME, CLOCK_REALTIME);
DEFINE(__CLOCK_MONOTONIC, CLOCK_MONOTONIC);
DEFINE(__CLOCK_REALTIME_COARSE, CLOCK_REALTIME_COARSE);
DEFINE(__CLOCK_MONOTONIC_COARSE, CLOCK_MONOTONIC_COARSE);
DEFINE(__CLOCK_THREAD_CPUTIME_ID, CLOCK_THREAD_CPUTIME_ID);
DEFINE(__CLOCK_REALTIME_RES, MONOTONIC_RES_NSEC);
DEFINE(__CLOCK_COARSE_RES, LOW_RES_NSEC);
BLANK();
/* idle data offsets */
OFFSET(__CLOCK_IDLE_ENTER, s390_idle_data, clock_idle_enter);
OFFSET(__CLOCK_IDLE_EXIT, s390_idle_data, clock_idle_exit);
OFFSET(__TIMER_IDLE_ENTER, s390_idle_data, timer_idle_enter);
OFFSET(__TIMER_IDLE_EXIT, s390_idle_data, timer_idle_exit);
BLANK();
/* hardware defined lowcore locations 0x000 - 0x1ff */
OFFSET(__LC_EXT_PARAMS, lowcore, ext_params);
OFFSET(__LC_EXT_CPU_ADDR, lowcore, ext_cpu_addr);
OFFSET(__LC_EXT_INT_CODE, lowcore, ext_int_code);
OFFSET(__LC_SVC_ILC, lowcore, svc_ilc);
OFFSET(__LC_SVC_INT_CODE, lowcore, svc_code);
OFFSET(__LC_PGM_ILC, lowcore, pgm_ilc);
OFFSET(__LC_PGM_INT_CODE, lowcore, pgm_code);
OFFSET(__LC_DATA_EXC_CODE, lowcore, data_exc_code);
OFFSET(__LC_MON_CLASS_NR, lowcore, mon_class_num);
OFFSET(__LC_PER_CODE, lowcore, per_code);
OFFSET(__LC_PER_ATMID, lowcore, per_atmid);
OFFSET(__LC_PER_ADDRESS, lowcore, per_address);
OFFSET(__LC_EXC_ACCESS_ID, lowcore, exc_access_id);
OFFSET(__LC_PER_ACCESS_ID, lowcore, per_access_id);
OFFSET(__LC_OP_ACCESS_ID, lowcore, op_access_id);
OFFSET(__LC_AR_MODE_ID, lowcore, ar_mode_id);
OFFSET(__LC_TRANS_EXC_CODE, lowcore, trans_exc_code);
OFFSET(__LC_MON_CODE, lowcore, monitor_code);
OFFSET(__LC_SUBCHANNEL_ID, lowcore, subchannel_id);
OFFSET(__LC_SUBCHANNEL_NR, lowcore, subchannel_nr);
OFFSET(__LC_IO_INT_PARM, lowcore, io_int_parm);
OFFSET(__LC_IO_INT_WORD, lowcore, io_int_word);
OFFSET(__LC_STFL_FAC_LIST, lowcore, stfl_fac_list);
OFFSET(__LC_STFLE_FAC_LIST, lowcore, stfle_fac_list);
OFFSET(__LC_MCCK_CODE, lowcore, mcck_interruption_code);
OFFSET(__LC_EXT_DAMAGE_CODE, lowcore, external_damage_code);
OFFSET(__LC_MCCK_FAIL_STOR_ADDR, lowcore, failing_storage_address);
OFFSET(__LC_LAST_BREAK, lowcore, breaking_event_addr);
OFFSET(__LC_RETURN_LPSWE, lowcore, return_lpswe);
OFFSET(__LC_RETURN_MCCK_LPSWE, lowcore, return_mcck_lpswe);
OFFSET(__LC_RST_OLD_PSW, lowcore, restart_old_psw);
OFFSET(__LC_EXT_OLD_PSW, lowcore, external_old_psw);
OFFSET(__LC_SVC_OLD_PSW, lowcore, svc_old_psw);
OFFSET(__LC_PGM_OLD_PSW, lowcore, program_old_psw);
OFFSET(__LC_MCK_OLD_PSW, lowcore, mcck_old_psw);
OFFSET(__LC_IO_OLD_PSW, lowcore, io_old_psw);
OFFSET(__LC_RST_NEW_PSW, lowcore, restart_psw);
OFFSET(__LC_EXT_NEW_PSW, lowcore, external_new_psw);
OFFSET(__LC_SVC_NEW_PSW, lowcore, svc_new_psw);
OFFSET(__LC_PGM_NEW_PSW, lowcore, program_new_psw);
OFFSET(__LC_MCK_NEW_PSW, lowcore, mcck_new_psw);
OFFSET(__LC_IO_NEW_PSW, lowcore, io_new_psw);
/* software defined lowcore locations 0x200 - 0xdff*/
OFFSET(__LC_SAVE_AREA_SYNC, lowcore, save_area_sync);
OFFSET(__LC_SAVE_AREA_ASYNC, lowcore, save_area_async);
OFFSET(__LC_SAVE_AREA_RESTART, lowcore, save_area_restart);
OFFSET(__LC_CPU_FLAGS, lowcore, cpu_flags);
OFFSET(__LC_RETURN_PSW, lowcore, return_psw);
OFFSET(__LC_RETURN_MCCK_PSW, lowcore, return_mcck_psw);
OFFSET(__LC_SYNC_ENTER_TIMER, lowcore, sync_enter_timer);
OFFSET(__LC_ASYNC_ENTER_TIMER, lowcore, async_enter_timer);
OFFSET(__LC_MCCK_ENTER_TIMER, lowcore, mcck_enter_timer);
OFFSET(__LC_EXIT_TIMER, lowcore, exit_timer);
OFFSET(__LC_USER_TIMER, lowcore, user_timer);
OFFSET(__LC_SYSTEM_TIMER, lowcore, system_timer);
OFFSET(__LC_STEAL_TIMER, lowcore, steal_timer);
OFFSET(__LC_LAST_UPDATE_TIMER, lowcore, last_update_timer);
OFFSET(__LC_LAST_UPDATE_CLOCK, lowcore, last_update_clock);
OFFSET(__LC_INT_CLOCK, lowcore, int_clock);
OFFSET(__LC_MCCK_CLOCK, lowcore, mcck_clock);
OFFSET(__LC_CLOCK_COMPARATOR, lowcore, clock_comparator);
OFFSET(__LC_BOOT_CLOCK, lowcore, boot_clock);
OFFSET(__LC_CURRENT, lowcore, current_task);
OFFSET(__LC_KERNEL_STACK, lowcore, kernel_stack);
OFFSET(__LC_ASYNC_STACK, lowcore, async_stack);
OFFSET(__LC_NODAT_STACK, lowcore, nodat_stack);
OFFSET(__LC_RESTART_STACK, lowcore, restart_stack);
OFFSET(__LC_RESTART_FN, lowcore, restart_fn);
OFFSET(__LC_RESTART_DATA, lowcore, restart_data);
OFFSET(__LC_RESTART_SOURCE, lowcore, restart_source);
OFFSET(__LC_USER_ASCE, lowcore, user_asce);
OFFSET(__LC_VDSO_ASCE, lowcore, vdso_asce);
OFFSET(__LC_LPP, lowcore, lpp);
OFFSET(__LC_CURRENT_PID, lowcore, current_pid);
OFFSET(__LC_PERCPU_OFFSET, lowcore, percpu_offset);
OFFSET(__LC_VDSO_PER_CPU, lowcore, vdso_per_cpu_data);
OFFSET(__LC_MACHINE_FLAGS, lowcore, machine_flags);
OFFSET(__LC_PREEMPT_COUNT, lowcore, preempt_count);
OFFSET(__LC_GMAP, lowcore, gmap);
OFFSET(__LC_BR_R1, lowcore, br_r1_trampoline);
/* software defined ABI-relevant lowcore locations 0xe00 - 0xe20 */
OFFSET(__LC_DUMP_REIPL, lowcore, ipib);
/* hardware defined lowcore locations 0x1000 - 0x18ff */
OFFSET(__LC_MCESAD, lowcore, mcesad);
OFFSET(__LC_EXT_PARAMS2, lowcore, ext_params2);
OFFSET(__LC_FPREGS_SAVE_AREA, lowcore, floating_pt_save_area);
OFFSET(__LC_GPREGS_SAVE_AREA, lowcore, gpregs_save_area);
OFFSET(__LC_PSW_SAVE_AREA, lowcore, psw_save_area);
OFFSET(__LC_PREFIX_SAVE_AREA, lowcore, prefixreg_save_area);
OFFSET(__LC_FP_CREG_SAVE_AREA, lowcore, fpt_creg_save_area);
OFFSET(__LC_TOD_PROGREG_SAVE_AREA, lowcore, tod_progreg_save_area);
OFFSET(__LC_CPU_TIMER_SAVE_AREA, lowcore, cpu_timer_save_area);
OFFSET(__LC_CLOCK_COMP_SAVE_AREA, lowcore, clock_comp_save_area);
OFFSET(__LC_AREGS_SAVE_AREA, lowcore, access_regs_save_area);
OFFSET(__LC_CREGS_SAVE_AREA, lowcore, cregs_save_area);
OFFSET(__LC_PGM_TDB, lowcore, pgm_tdb);
BLANK();
/* extended machine check save area */
OFFSET(__MCESA_GS_SAVE_AREA, mcesa, guarded_storage_save_area);
BLANK();
/* gmap/sie offsets */
OFFSET(__GMAP_ASCE, gmap, asce);
OFFSET(__SIE_PROG0C, kvm_s390_sie_block, prog0c);
OFFSET(__SIE_PROG20, kvm_s390_sie_block, prog20);
/* kexec_sha_region */
OFFSET(__KEXEC_SHA_REGION_START, kexec_sha_region, start);
OFFSET(__KEXEC_SHA_REGION_LEN, kexec_sha_region, len);
DEFINE(__KEXEC_SHA_REGION_SIZE, sizeof(struct kexec_sha_region));
return 0;
}