diff options
Diffstat (limited to 'arch/x86/entry')
| -rw-r--r-- | arch/x86/entry/entry_32.S | 43 | ||||
| -rw-r--r-- | arch/x86/entry/vdso/vclock_gettime.c | 6 | ||||
| -rw-r--r-- | arch/x86/entry/vsyscall/vsyscall_64.c | 6 |
3 files changed, 48 insertions, 7 deletions
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 5832b11f01bb..7e0560442538 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -1090,7 +1090,6 @@ SYM_FUNC_START(entry_INT80_32) restore_all: TRACE_IRQS_IRET SWITCH_TO_ENTRY_STACK -.Lrestore_all_notrace: CHECK_AND_APPLY_ESPFIX .Lrestore_nocheck: /* Switch back to user CR3 */ @@ -1537,6 +1536,48 @@ SYM_CODE_START(debug) jmp common_exception SYM_CODE_END(debug) +#ifdef CONFIG_DOUBLEFAULT +SYM_CODE_START(double_fault) +1: + /* + * This is a task gate handler, not an interrupt gate handler. + * The error code is on the stack, but the stack is otherwise + * empty. Interrupts are off. Our state is sane with the following + * exceptions: + * + * - CR0.TS is set. "TS" literally means "task switched". + * - EFLAGS.NT is set because we're a "nested task". + * - The doublefault TSS has back_link set and has been marked busy. + * - TR points to the doublefault TSS and the normal TSS is busy. + * - CR3 is the normal kernel PGD. This would be delightful, except + * that the CPU didn't bother to save the old CR3 anywhere. This + * would make it very awkward to return back to the context we came + * from. + * + * The rest of EFLAGS is sanitized for us, so we don't need to + * worry about AC or DF. + * + * Don't even bother popping the error code. It's always zero, + * and ignoring it makes us a bit more robust against buggy + * hypervisor task gate implementations. + * + * We will manually undo the task switch instead of doing a + * task-switching IRET. + */ + + clts /* clear CR0.TS */ + pushl $X86_EFLAGS_FIXED + popfl /* clear EFLAGS.NT */ + + call doublefault_shim + + /* We don't support returning, so we have no IRET here. */ +1: + hlt + jmp 1b +SYM_CODE_END(double_fault) +#endif + /* * NMI is doubly nasty. It can happen on the first instruction of * entry_SYSENTER_32 (just like #DB), but it can also interrupt the beginning diff --git a/arch/x86/entry/vdso/vclock_gettime.c b/arch/x86/entry/vdso/vclock_gettime.c index d9ff616bb0f6..7d70935b6758 100644 --- a/arch/x86/entry/vdso/vclock_gettime.c +++ b/arch/x86/entry/vdso/vclock_gettime.c @@ -15,7 +15,7 @@ #include "../../../../lib/vdso/gettimeofday.c" extern int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz); -extern time_t __vdso_time(time_t *t); +extern __kernel_old_time_t __vdso_time(__kernel_old_time_t *t); int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz) { @@ -25,12 +25,12 @@ int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz) int gettimeofday(struct __kernel_old_timeval *, struct timezone *) __attribute__((weak, alias("__vdso_gettimeofday"))); -time_t __vdso_time(time_t *t) +__kernel_old_time_t __vdso_time(__kernel_old_time_t *t) { return __cvdso_time(t); } -time_t time(time_t *t) __attribute__((weak, alias("__vdso_time"))); +__kernel_old_time_t time(__kernel_old_time_t *t) __attribute__((weak, alias("__vdso_time"))); #if defined(CONFIG_X86_64) && !defined(BUILD_VDSO32_64) diff --git a/arch/x86/entry/vsyscall/vsyscall_64.c b/arch/x86/entry/vsyscall/vsyscall_64.c index e7c596dea947..44c33103a955 100644 --- a/arch/x86/entry/vsyscall/vsyscall_64.c +++ b/arch/x86/entry/vsyscall/vsyscall_64.c @@ -184,7 +184,7 @@ bool emulate_vsyscall(unsigned long error_code, */ switch (vsyscall_nr) { case 0: - if (!write_ok_or_segv(regs->di, sizeof(struct timeval)) || + if (!write_ok_or_segv(regs->di, sizeof(struct __kernel_old_timeval)) || !write_ok_or_segv(regs->si, sizeof(struct timezone))) { ret = -EFAULT; goto check_fault; @@ -194,7 +194,7 @@ bool emulate_vsyscall(unsigned long error_code, break; case 1: - if (!write_ok_or_segv(regs->di, sizeof(time_t))) { + if (!write_ok_or_segv(regs->di, sizeof(__kernel_old_time_t))) { ret = -EFAULT; goto check_fault; } @@ -222,7 +222,7 @@ bool emulate_vsyscall(unsigned long error_code, */ regs->orig_ax = syscall_nr; regs->ax = -ENOSYS; - tmp = secure_computing(NULL); + tmp = secure_computing(); if ((!tmp && regs->orig_ax != syscall_nr) || regs->ip != address) { warn_bad_vsyscall(KERN_DEBUG, regs, "seccomp tried to change syscall nr or ip"); |