linux-kernel - [PATCH v2] riscv: Return -EFAULT if copy_{to,from}

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Message-Id: <1615017149-24843-1-git-send-email-yangtiezhu@loongson.cn>
Date:   Sat,  6 Mar 2021 15:52:29 +0800
From:   Tiezhu Yang <yangtiezhu@...ngson.cn>
To:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>
Cc:     linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] riscv: Return -EFAULT if copy_{to,from}_user() failed in signal.c

copy_{to,from}_user() returns the amount left to copy, it should return
-EFAULT error code if copy {to,from} user failed, just like the return
value is an error code when {put,get}_user() failed, this is to make the
return value consistent, no function change.

Signed-off-by: Tiezhu Yang <yangtiezhu@...ngson.cn>
---
 arch/riscv/kernel/signal.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c
index 65942b3..c76d877 100644
--- a/arch/riscv/kernel/signal.c
+++ b/arch/riscv/kernel/signal.c
@@ -39,7 +39,7 @@ static long restore_fp_state(struct pt_regs *regs,
 
 	err = __copy_from_user(&current->thread.fstate, state, sizeof(*state));
 	if (unlikely(err))
-		return err;
+		return -EFAULT;
 
 	fstate_restore(current, regs);
 
@@ -67,7 +67,7 @@ static long save_fp_state(struct pt_regs *regs,
 	fstate_save(current, regs);
 	err = __copy_to_user(state, &current->thread.fstate, sizeof(*state));
 	if (unlikely(err))
-		return err;
+		return -EFAULT;
 
 	/* We support no other extension state at this time. */
 	for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) {
@@ -87,8 +87,12 @@ static long restore_sigcontext(struct pt_regs *regs,
 	struct sigcontext __user *sc)
 {
 	long err;
+
 	/* sc_regs is structured the same as the start of pt_regs */
 	err = __copy_from_user(regs, &sc->sc_regs, sizeof(sc->sc_regs));
+	if (unlikely(err))
+		return -EFAULT;
+
 	/* Restore the floating-point state. */
 	if (has_fpu)
 		err |= restore_fp_state(regs, &sc->sc_fpregs);
@@ -140,8 +144,12 @@ static long setup_sigcontext(struct rt_sigframe __user *frame,
 {
 	struct sigcontext __user *sc = &frame->uc.uc_mcontext;
 	long err;
+
 	/* sc_regs is structured the same as the start of pt_regs */
 	err = __copy_to_user(&sc->sc_regs, regs, sizeof(sc->sc_regs));
+	if (unlikely(err))
+		return -EFAULT;
+
 	/* Save the floating-point state. */
 	if (has_fpu)
 		err |= save_fp_state(regs, &sc->sc_fpregs);
-- 
2.1.0