linux-kernel - [PATCH v2 08/25] powerpc/signal: Move access_ok() out of get

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Date:   Tue, 18 Aug 2020 17:19:20 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v2 08/25] powerpc/signal: Move access_ok() out of
 get_sigframe()

This access_ok() will soon be performed by user_access_begin().
So move it out of get_sigframe().

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 arch/powerpc/kernel/signal.c    | 4 ----
 arch/powerpc/kernel/signal_32.c | 4 ++--
 arch/powerpc/kernel/signal_64.c | 2 +-
 3 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
index 3b56db02b762..1be5fd01f866 100644
--- a/arch/powerpc/kernel/signal.c
+++ b/arch/powerpc/kernel/signal.c
@@ -154,10 +154,6 @@ void __user *get_sigframe(struct ksignal *ksig, unsigned long sp,
 	oldsp = sigsp(oldsp, ksig);
 	newsp = (oldsp - frame_size) & ~0xFUL;
 
-	/* Check access */
-	if (!access_ok((void __user *)newsp, oldsp - newsp))
-		return NULL;
-
         return (void __user *)newsp;
 }
 
diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 8cbc9ac1343d..61621acacc63 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -768,7 +768,7 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
 	/* Put a Real Time Context onto stack */
 	rt_sf = get_sigframe(ksig, get_tm_stackpointer(tsk), sizeof(*rt_sf), 1);
 	addr = rt_sf;
-	if (unlikely(rt_sf == NULL))
+	if (!access_ok(rt_sf, sizeof(*rt_sf)))
 		goto badframe;
 
 	/* Put the siginfo & fill in most of the ucontext */
@@ -1227,7 +1227,7 @@ int handle_signal32(struct ksignal *ksig, sigset_t *oldset,
 
 	/* Set up Signal Frame */
 	frame = get_sigframe(ksig, get_tm_stackpointer(tsk), sizeof(*frame), 1);
-	if (unlikely(frame == NULL))
+	if (!access_ok(frame, sizeof(*frame)))
 		goto badframe;
 	sc = (struct sigcontext __user *) &frame->sctx;
 
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index cae612bdde5f..d3db78732070 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -823,7 +823,7 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set,
 #endif
 
 	frame = get_sigframe(ksig, get_tm_stackpointer(tsk), sizeof(*frame), 0);
-	if (unlikely(frame == NULL))
+	if (!access_ok(frame, sizeof(*frame)))
 		goto badframe;
 
 	err |= __put_user(&frame->info, &frame->pinfo);
-- 
2.25.0