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new helpers: __save_altstack/__compat_save_altstack, switch x86 and um to those

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note that they are relying on access_ok() already checked by caller.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2012-11-20 14:24:26 -05:00
parent 9026843952
commit c40702c49f
6 changed files with 25 additions and 25 deletions
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5
arch/x86/ia32/ia32_signal.c
View file

@ -467,10 +467,7 @@ int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
else
put_user_ex(0, &frame->uc.uc_flags);
put_user_ex(0, &frame->uc.uc_link);
put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
put_user_ex(sas_ss_flags(regs->sp),
&frame->uc.uc_stack.ss_flags);
put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
err |= __compat_save_altstack(&frame->uc.uc_stack, regs->sp);
if (ka->sa.sa_flags & SA_RESTORER)
restorer = ka->sa.sa_restorer;

18
arch/x86/kernel/signal.c
View file

@ -363,10 +363,7 @@ static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
else
put_user_ex(0, &frame->uc.uc_flags);
put_user_ex(0, &frame->uc.uc_link);
put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
put_user_ex(sas_ss_flags(regs->sp),
&frame->uc.uc_stack.ss_flags);
put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
/* Set up to return from userspace. */
restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
@ -413,7 +410,6 @@ static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
struct rt_sigframe __user *frame;
void __user *fp = NULL;
int err = 0;
struct task_struct *me = current;
frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe), &fp);
@ -432,10 +428,7 @@ static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
else
put_user_ex(0, &frame->uc.uc_flags);
put_user_ex(0, &frame->uc.uc_link);
put_user_ex(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
put_user_ex(sas_ss_flags(regs->sp),
&frame->uc.uc_stack.ss_flags);
put_user_ex(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
/* Set up to return from userspace. If provided, use a stub
already in userspace. */
@ -502,10 +495,7 @@ static int x32_setup_rt_frame(int sig, struct k_sigaction *ka,
else
put_user_ex(0, &frame->uc.uc_flags);
put_user_ex(0, &frame->uc.uc_link);
put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
put_user_ex(sas_ss_flags(regs->sp),
&frame->uc.uc_stack.ss_flags);
put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
err |= __compat_save_altstack(&frame->uc.uc_stack, regs->sp);
put_user_ex(0, &frame->uc.uc__pad0);
if (ka->sa.sa_flags & SA_RESTORER) {
@ -651,7 +641,7 @@ long sys_rt_sigreturn(struct pt_regs *regs)
if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
goto badframe;
if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
if (restore_altstack(&frame->uc.uc_stack))
goto badframe;
return ax;

9
arch/x86/um/signal.c
View file

@ -342,9 +342,7 @@ static int copy_ucontext_to_user(struct ucontext __user *uc,
{
int err = 0;
err |= put_user(current->sas_ss_sp, &uc->uc_stack.ss_sp);
err |= put_user(sas_ss_flags(sp), &uc->uc_stack.ss_flags);
err |= put_user(current->sas_ss_size, &uc->uc_stack.ss_size);
err |= __save_altstack(&uc->uc_stack, sp);
err |= copy_sc_to_user(&uc->uc_mcontext, fp, &current->thread.regs, 0);
err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set));
return err;
@ -529,10 +527,7 @@ int setup_signal_stack_si(unsigned long stack_top, int sig,
/* Create the ucontext. */
err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(0, &frame->uc.uc_link);
err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
err |= __put_user(sas_ss_flags(PT_REGS_SP(regs)),
&frame->uc.uc_stack.ss_flags);
err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
err |= __save_altstack(&frame->uc.uc_stack, PT_REGS_SP(regs));
err |= copy_sc_to_user(&frame->uc.uc_mcontext, &frame->fpstate, regs,
set->sig[0]);
err |= __put_user(&frame->fpstate, &frame->uc.uc_mcontext.fpstate);

1
include/linux/compat.h
View file

@ -647,6 +647,7 @@ asmlinkage long compat_sys_sigaltstack(const compat_stack_t __user *uss_ptr,
compat_stack_t __user *uoss_ptr);
int compat_restore_altstack(const compat_stack_t __user *uss);
int __compat_save_altstack(compat_stack_t __user *, unsigned long);
#endif
#else

1
include/linux/signal.h
View file

@ -386,5 +386,6 @@ int unhandled_signal(struct task_struct *tsk, int sig);
void signals_init(void);
int restore_altstack(const stack_t __user *);
int __save_altstack(stack_t __user *, unsigned long);
#endif /* _LINUX_SIGNAL_H */

16
kernel/signal.c
View file

@ -3117,6 +3117,14 @@ int restore_altstack(const stack_t __user *uss)
return err == -EFAULT ? err : 0;
}
int __save_altstack(stack_t __user *uss, unsigned long sp)
{
struct task_struct *t = current;
return __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
__put_user(sas_ss_flags(sp), &uss->ss_flags) |
__put_user(t->sas_ss_size, &uss->ss_size);
}
#ifdef CONFIG_COMPAT
#ifdef CONFIG_GENERIC_SIGALTSTACK
asmlinkage long compat_sys_sigaltstack(const compat_stack_t __user *uss_ptr,
@ -3158,6 +3166,14 @@ int compat_restore_altstack(const compat_stack_t __user *uss)
/* squash all but -EFAULT for now */
return err == -EFAULT ? err : 0;
}
int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
{
struct task_struct *t = current;
return __put_user(ptr_to_compat((void __user *)t->sas_ss_sp), &uss->ss_sp) |
__put_user(sas_ss_flags(sp), &uss->ss_flags) |
__put_user(t->sas_ss_size, &uss->ss_size);
}
#endif
#endif