linux-kernel - [RFC][PATCH 15/22] x86: ia32_setup_rt_frame(): consolidate uaccess areas

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Message-Id: <20200323183819.250124-15-viro@ZenIV.linux.org.uk>
Date:   Mon, 23 Mar 2020 18:38:12 +0000
From:   Al Viro <viro@...IV.linux.org.uk>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Thomas Gleixner <tglx@...utronix.de>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [RFC][PATCH 15/22] x86: ia32_setup_rt_frame(): consolidate uaccess areas

From: Al Viro <viro@...iv.linux.org.uk>

__copy_siginfo_to_user32() call reordered a bit.  The rest folds
nicely.

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
 arch/x86/ia32/ia32_signal.c | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index 4dae24f42e1a..b97087812d26 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -296,10 +296,9 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
 {
 	struct rt_sigframe_ia32 __user *frame;
 	void __user *restorer;
-	int err = 0;
 	void __user *fpstate = NULL;
 
-	/* __copy_to_user optimizes that into a single 8 byte store */
+	/* unsafe_put_user optimizes that into a single 8 byte store */
 	static const struct {
 		u8 movl;
 		u32 val;
@@ -341,17 +340,13 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
 	 * versions need it.
 	 */
 	unsafe_put_user(*((u64 *)&code), (u64 __user *)frame->retcode, Efault);
+	if (ia32_setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
+				     regs, set->sig[0]))
+		goto Efault;
+	unsafe_put_user(*(__u64 *)set, (__u64 *)&frame->uc.uc_sigmask, Efault);
 	user_access_end();
 
-	err |= __copy_siginfo_to_user32(&frame->info, &ksig->info, false);
-	if (!user_access_begin(&frame->uc.uc_mcontext, sizeof(struct sigcontext_32)))
-		return -EFAULT;
-	err |= ia32_setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
-				     regs, set->sig[0]);
-	user_access_end();
-	err |= __put_user(*(__u64 *)set, (__u64 __user *)&frame->uc.uc_sigmask);
-
-	if (err)
+	if (__copy_siginfo_to_user32(&frame->info, &ksig->info, false))
 		return -EFAULT;
 
 	/* Set up registers for signal handler */
-- 
2.11.0