linux/arch/s390/kernel/entry.h
Heiko Carstens b5a882fcf1 s390: restore address space when returning to user space
Unbalanced set_fs usages (e.g. early exit from a function and a
forgotten set_fs(USER_DS) call) may lead to a situation where the
secondary asce is the kernel space asce when returning to user
space. This would allow user space to modify kernel space at will.

This would only be possible with the above mentioned kernel bug,
however we can detect this and fix the secondary asce before returning
to user space.

Therefore a new TIF_ASCE_SECONDARY which is used within set_fs. When
returning to user space check if TIF_ASCE_SECONDARY is set, which
would indicate a bug. If it is set print a message to the console,
fixup the secondary asce, and then return to user space.

This is similar to what is being discussed for x86 and arm:
"[RFC] syscalls: Restore address limit after a syscall".

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-02-23 10:06:38 +01:00

86 lines
2.8 KiB
C

#ifndef _ENTRY_H
#define _ENTRY_H
#include <linux/percpu.h>
#include <linux/types.h>
#include <linux/signal.h>
#include <asm/ptrace.h>
#include <asm/idle.h>
extern void *restart_stack;
extern unsigned long suspend_zero_pages;
void system_call(void);
void pgm_check_handler(void);
void ext_int_handler(void);
void io_int_handler(void);
void mcck_int_handler(void);
void restart_int_handler(void);
void restart_call_handler(void);
asmlinkage long do_syscall_trace_enter(struct pt_regs *regs);
asmlinkage void do_syscall_trace_exit(struct pt_regs *regs);
void do_protection_exception(struct pt_regs *regs);
void do_dat_exception(struct pt_regs *regs);
void addressing_exception(struct pt_regs *regs);
void data_exception(struct pt_regs *regs);
void default_trap_handler(struct pt_regs *regs);
void divide_exception(struct pt_regs *regs);
void execute_exception(struct pt_regs *regs);
void hfp_divide_exception(struct pt_regs *regs);
void hfp_overflow_exception(struct pt_regs *regs);
void hfp_significance_exception(struct pt_regs *regs);
void hfp_sqrt_exception(struct pt_regs *regs);
void hfp_underflow_exception(struct pt_regs *regs);
void illegal_op(struct pt_regs *regs);
void operand_exception(struct pt_regs *regs);
void overflow_exception(struct pt_regs *regs);
void privileged_op(struct pt_regs *regs);
void space_switch_exception(struct pt_regs *regs);
void special_op_exception(struct pt_regs *regs);
void specification_exception(struct pt_regs *regs);
void transaction_exception(struct pt_regs *regs);
void translation_exception(struct pt_regs *regs);
void vector_exception(struct pt_regs *regs);
void do_per_trap(struct pt_regs *regs);
void do_report_trap(struct pt_regs *regs, int si_signo, int si_code, char *str);
void syscall_trace(struct pt_regs *regs, int entryexit);
void kernel_stack_overflow(struct pt_regs * regs);
void do_signal(struct pt_regs *regs);
void handle_signal32(struct ksignal *ksig, sigset_t *oldset,
struct pt_regs *regs);
void do_notify_resume(struct pt_regs *regs);
void __init init_IRQ(void);
void do_IRQ(struct pt_regs *regs, int irq);
void do_restart(void);
void __init startup_init(void);
void die(struct pt_regs *regs, const char *str);
int setup_profiling_timer(unsigned int multiplier);
void __init time_init(void);
int pfn_is_nosave(unsigned long);
void s390_early_resume(void);
unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip);
struct s390_mmap_arg_struct;
struct fadvise64_64_args;
struct old_sigaction;
long sys_rt_sigreturn(void);
long sys_sigreturn(void);
long sys_s390_personality(unsigned int personality);
long sys_s390_runtime_instr(int command, int signum);
long sys_s390_pci_mmio_write(unsigned long, const void __user *, size_t);
long sys_s390_pci_mmio_read(unsigned long, void __user *, size_t);
DECLARE_PER_CPU(u64, mt_cycles[8]);
void verify_facilities(void);
void set_fs_fixup(void);
#endif /* _ENTRY_H */