[tip: x86/cleanups] x86: __setup_rt_frame(): consolidate uaccess areas

From: tip-bot2 for Al Viro
Date: Sat Mar 28 2020 - 06:59:58 EST


The following commit has been merged into the x86/cleanups branch of tip:

Commit-ID: ead8e4e7e2c75ced6fcd9a53d3e9a2ecd7368553
Gitweb: https://git.kernel.org/tip/ead8e4e7e2c75ced6fcd9a53d3e9a2ecd7368553
Author: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
AuthorDate: Sat, 15 Feb 2020 21:22:39 -05:00
Committer: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
CommitterDate: Thu, 26 Mar 2020 14:57:10 -04:00

x86: __setup_rt_frame(): consolidate uaccess areas

reorder copy_siginfo_to_user() calls a bit

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/signal.c | 26 +++++++++-----------------
1 file changed, 9 insertions(+), 17 deletions(-)

diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 38ff834..e37d5a1 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -357,7 +357,6 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig,
{
struct rt_sigframe __user *frame;
void __user *restorer;
- int err = 0;
void __user *fp = NULL;

frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fp);
@@ -393,11 +392,11 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig,
*/
unsafe_put_user(*((u64 *)&rt_retcode), (u64 *)frame->retcode, Efault);
unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault);
+ unsafe_put_user(*(__u64 *)set,
+ (__u64 __user *)&frame->uc.uc_sigmask, Efault);
user_access_end();

- err |= copy_siginfo_to_user(&frame->info, &ksig->info);
- err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
- if (err)
+ if (copy_siginfo_to_user(&frame->info, &ksig->info))
return -EFAULT;

/* Set up registers for signal handler */
@@ -439,23 +438,14 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig,
struct rt_sigframe __user *frame;
void __user *fp = NULL;
unsigned long uc_flags;
- int err = 0;

/* x86-64 should always use SA_RESTORER. */
if (!(ksig->ka.sa.sa_flags & SA_RESTORER))
return -EFAULT;

frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp);
-
- if (!access_ok(frame, sizeof(*frame)))
- return -EFAULT;
-
- if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
- if (copy_siginfo_to_user(&frame->info, &ksig->info))
- return -EFAULT;
- }
-
uc_flags = frame_uc_flags(regs);
+
if (!user_access_begin(frame, sizeof(*frame)))
return -EFAULT;

@@ -468,11 +458,13 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig,
already in userspace. */
unsafe_put_user(ksig->ka.sa.sa_restorer, &frame->pretcode, Efault);
unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault);
+ unsafe_put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0], Efault);
user_access_end();
- err |= __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);

- if (err)
- return -EFAULT;
+ if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
+ if (copy_siginfo_to_user(&frame->info, &ksig->info))
+ return -EFAULT;
+ }

/* Set up registers for signal handler */
regs->di = sig;