x86: get rid of put_user_try in {ia32,x32}_setup_rt_frame()

Straightforward, except for compat_save_altstack_ex() stuck in those.
Replace that thing with an analogue that would use unsafe_put_user()
instead of put_user_ex() (called unsafe_compat_save_altstack()) and
be done with that...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index af673ec..a96995a 100644 (file)
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -326,35 +326,34 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
 
        frame = get_sigframe(ksig, regs, sizeof(*frame), &fpstate);
 
-       if (!access_ok(frame, sizeof(*frame)))
+       if (!user_access_begin(frame, sizeof(*frame)))
                return -EFAULT;
 
-       put_user_try {
-               put_user_ex(sig, &frame->sig);
-               put_user_ex(ptr_to_compat(&frame->info), &frame->pinfo);
-               put_user_ex(ptr_to_compat(&frame->uc), &frame->puc);
+       unsafe_put_user(sig, &frame->sig, Efault);
+       unsafe_put_user(ptr_to_compat(&frame->info), &frame->pinfo, Efault);
+       unsafe_put_user(ptr_to_compat(&frame->uc), &frame->puc, Efault);
 
-               /* Create the ucontext.  */
-               if (static_cpu_has(X86_FEATURE_XSAVE))
-                       put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
-               else
-                       put_user_ex(0, &frame->uc.uc_flags);
-               put_user_ex(0, &frame->uc.uc_link);
-               compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp);
+       /* Create the ucontext.  */
+       if (static_cpu_has(X86_FEATURE_XSAVE))
+               unsafe_put_user(UC_FP_XSTATE, &frame->uc.uc_flags, Efault);
+       else
+               unsafe_put_user(0, &frame->uc.uc_flags, Efault);
+       unsafe_put_user(0, &frame->uc.uc_link, Efault);
+       unsafe_compat_save_altstack(&frame->uc.uc_stack, regs->sp, Efault);
 
-               if (ksig->ka.sa.sa_flags & SA_RESTORER)
-                       restorer = ksig->ka.sa.sa_restorer;
-               else
-                       restorer = current->mm->context.vdso +
-                               vdso_image_32.sym___kernel_rt_sigreturn;
-               put_user_ex(ptr_to_compat(restorer), &frame->pretcode);
+       if (ksig->ka.sa.sa_flags & SA_RESTORER)
+               restorer = ksig->ka.sa.sa_restorer;
+       else
+               restorer = current->mm->context.vdso +
+                       vdso_image_32.sym___kernel_rt_sigreturn;
+       unsafe_put_user(ptr_to_compat(restorer), &frame->pretcode, Efault);
 
-               /*
-                * Not actually used anymore, but left because some gdb
-                * versions need it.
-                */
-               put_user_ex(*((u64 *)&code), (u64 __user *)frame->retcode);
-       } put_user_catch(err);
+       /*
+        * Not actually used anymore, but left because some gdb
+        * versions need it.
+        */
+       unsafe_put_user(*((u64 *)&code), (u64 __user *)frame->retcode, Efault);
+       user_access_end();
 
        err |= __copy_siginfo_to_user32(&frame->info, &ksig->info, false);
        err |= ia32_setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
@@ -380,4 +379,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
        regs->ss = __USER32_DS;
 
        return 0;
+Efault:
+       user_access_end();
+       return -EFAULT;
 }

diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 3b4ca48..29abad2 100644 (file)
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -529,6 +529,9 @@ static int x32_setup_rt_frame(struct ksignal *ksig,
        int err = 0;
        void __user *fpstate = NULL;
 
+       if (!(ksig->ka.sa.sa_flags & SA_RESTORER))
+               return -EFAULT;
+
        frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
 
        if (!access_ok(frame, sizeof(*frame)))
@@ -541,22 +544,17 @@ static int x32_setup_rt_frame(struct ksignal *ksig,
 
        uc_flags = frame_uc_flags(regs);
 
-       put_user_try {
-               /* Create the ucontext.  */
-               put_user_ex(uc_flags, &frame->uc.uc_flags);
-               put_user_ex(0, &frame->uc.uc_link);
-               compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp);
-               put_user_ex(0, &frame->uc.uc__pad0);
+       if (!user_access_begin(frame, sizeof(*frame)))
+               return -EFAULT;
 
-               if (ksig->ka.sa.sa_flags & SA_RESTORER) {
-                       restorer = ksig->ka.sa.sa_restorer;
-               } else {
-                       /* could use a vstub here */
-                       restorer = NULL;
-                       err |= -EFAULT;
-               }
-               put_user_ex(restorer, (unsigned long __user *)&frame->pretcode);
-       } put_user_catch(err);
+       /* Create the ucontext.  */
+       unsafe_put_user(uc_flags, &frame->uc.uc_flags, Efault);
+       unsafe_put_user(0, &frame->uc.uc_link, Efault);
+       unsafe_compat_save_altstack(&frame->uc.uc_stack, regs->sp, Efault);
+       unsafe_put_user(0, &frame->uc.uc__pad0, Efault);
+       restorer = ksig->ka.sa.sa_restorer;
+       unsafe_put_user(restorer, (unsigned long __user *)&frame->pretcode, Efault);
+       user_access_end();
 
        err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
                                regs, set->sig[0]);
@@ -582,6 +580,11 @@ static int x32_setup_rt_frame(struct ksignal *ksig,
 #endif /* CONFIG_X86_X32_ABI */
 
        return 0;
+#ifdef CONFIG_X86_X32_ABI
+Efault:
+       user_access_end();
+       return -EFAULT;
+#endif
 }
 
 /*

diff --git a/include/linux/compat.h b/include/linux/compat.h
index 11083d8..224ecb4 100644 (file)
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -483,12 +483,13 @@ extern void __user *compat_alloc_user_space(unsigned long len);
 
 int compat_restore_altstack(const compat_stack_t __user *uss);
 int __compat_save_altstack(compat_stack_t __user *, unsigned long);
-#define compat_save_altstack_ex(uss, sp) do { \
+#define unsafe_compat_save_altstack(uss, sp, label) do { \
        compat_stack_t __user *__uss = uss; \
        struct task_struct *t = current; \
-       put_user_ex(ptr_to_compat((void __user *)t->sas_ss_sp), &__uss->ss_sp); \
-       put_user_ex(t->sas_ss_flags, &__uss->ss_flags); \
-       put_user_ex(t->sas_ss_size, &__uss->ss_size); \
+       unsafe_put_user(ptr_to_compat((void __user *)t->sas_ss_sp), \
+                       &__uss->ss_sp, label); \
+       unsafe_put_user(t->sas_ss_flags, &__uss->ss_flags, label); \
+       unsafe_put_user(t->sas_ss_size, &__uss->ss_size, label); \
        if (t->sas_ss_flags & SS_AUTODISARM) \
                sas_ss_reset(t); \
 } while (0);