[RFC][PATCH v2 03/22] x86: switch sigframe sigset handling to explict __get_user()/__put_user()

From: Al Viro
Date: Thu Mar 26 2020 - 22:32:12 EST


From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

... and consolidate the definition of sigframe_ia32->extramask - it's
always a 1-element array of 32bit unsigned.

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
arch/x86/ia32/ia32_signal.c | 16 +++++-----------
arch/x86/include/asm/sigframe.h | 6 +-----
arch/x86/kernel/signal.c | 20 ++++++++------------
3 files changed, 14 insertions(+), 28 deletions(-)

diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index a3aefe9b9401..c72025d615f8 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -126,10 +126,7 @@ COMPAT_SYSCALL_DEFINE0(sigreturn)
if (!access_ok(frame, sizeof(*frame)))
goto badframe;
if (__get_user(set.sig[0], &frame->sc.oldmask)
- || (_COMPAT_NSIG_WORDS > 1
- && __copy_from_user((((char *) &set.sig) + 4),
- &frame->extramask,
- sizeof(frame->extramask))))
+ || __get_user(((__u32 *)&set)[1], &frame->extramask[0]))
goto badframe;

set_current_blocked(&set);
@@ -153,7 +150,7 @@ COMPAT_SYSCALL_DEFINE0(rt_sigreturn)

if (!access_ok(frame, sizeof(*frame)))
goto badframe;
- if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
+ if (__get_user(set.sig[0], (__u64 __user *)&frame->uc.uc_sigmask))
goto badframe;

set_current_blocked(&set);
@@ -277,11 +274,8 @@ int ia32_setup_frame(int sig, struct ksignal *ksig,
if (ia32_setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
return -EFAULT;

- if (_COMPAT_NSIG_WORDS > 1) {
- if (__copy_to_user(frame->extramask, &set->sig[1],
- sizeof(frame->extramask)))
- return -EFAULT;
- }
+ if (__put_user(set->sig[1], &frame->extramask[0]))
+ return -EFAULT;

if (ksig->ka.sa.sa_flags & SA_RESTORER) {
restorer = ksig->ka.sa.sa_restorer;
@@ -381,7 +375,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
err |= __copy_siginfo_to_user32(&frame->info, &ksig->info, false);
err |= ia32_setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
regs, set->sig[0]);
- err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+ err |= __put_user(*(__u64 *)set, (__u64 __user *)&frame->uc.uc_sigmask);

if (err)
return -EFAULT;
diff --git a/arch/x86/include/asm/sigframe.h b/arch/x86/include/asm/sigframe.h
index f176114c04d4..84eab2724875 100644
--- a/arch/x86/include/asm/sigframe.h
+++ b/arch/x86/include/asm/sigframe.h
@@ -33,11 +33,7 @@ struct sigframe_ia32 {
* legacy application accessing/modifying it.
*/
struct _fpstate_32 fpstate_unused;
-#ifdef CONFIG_IA32_EMULATION
- unsigned int extramask[_COMPAT_NSIG_WORDS-1];
-#else /* !CONFIG_IA32_EMULATION */
- unsigned long extramask[_NSIG_WORDS-1];
-#endif /* CONFIG_IA32_EMULATION */
+ unsigned int extramask[1];
char retcode[8];
/* fp state follows here */
};
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 8a29573851a3..53ac66b3fd9b 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -326,11 +326,8 @@ __setup_frame(int sig, struct ksignal *ksig, sigset_t *set,
if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
return -EFAULT;

- if (_NSIG_WORDS > 1) {
- if (__copy_to_user(&frame->extramask, &set->sig[1],
- sizeof(frame->extramask)))
- return -EFAULT;
- }
+ if (__put_user(set->sig[1], &frame->extramask[0]))
+ return -EFAULT;

if (current->mm->context.vdso)
restorer = current->mm->context.vdso +
@@ -489,7 +486,7 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig,
} put_user_catch(err);

err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
- err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+ err |= __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);

if (err)
return -EFAULT;
@@ -575,7 +572,7 @@ static int x32_setup_rt_frame(struct ksignal *ksig,

err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
regs, set->sig[0]);
- err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+ err |= __put_user(*(__u64 *)set, (__u64 __user *)&frame->uc.uc_sigmask);

if (err)
return -EFAULT;
@@ -613,9 +610,8 @@ SYSCALL_DEFINE0(sigreturn)

if (!access_ok(frame, sizeof(*frame)))
goto badframe;
- if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
- && __copy_from_user(&set.sig[1], &frame->extramask,
- sizeof(frame->extramask))))
+ if (__get_user(set.sig[0], &frame->sc.oldmask) ||
+ __get_user(set.sig[1], &frame->extramask[0]))
goto badframe;

set_current_blocked(&set);
@@ -645,7 +641,7 @@ SYSCALL_DEFINE0(rt_sigreturn)
frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
if (!access_ok(frame, sizeof(*frame)))
goto badframe;
- if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
+ if (__get_user(*(__u64 *)&set, (__u64 __user *)&frame->uc.uc_sigmask))
goto badframe;
if (__get_user(uc_flags, &frame->uc.uc_flags))
goto badframe;
@@ -870,7 +866,7 @@ asmlinkage long sys32_x32_rt_sigreturn(void)

if (!access_ok(frame, sizeof(*frame)))
goto badframe;
- if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
+ if (__get_user(set.sig[0], (__u64 __user *)&frame->uc.uc_sigmask))
goto badframe;
if (__get_user(uc_flags, &frame->uc.uc_flags))
goto badframe;
--
2.11.0