2021-12-20 04:27:51

by Tiezhu Yang

Subject: [PATCH v2 2/3] MIPS: signal: Return immediately if call fails

When debug sigaltstack(), copy_siginfo_to_user() fails first in
setup_rt_frame() if the alternate signal stack is too small, so
it should return immediately if call fails, no need to call the
following functions.

Signed-off-by: Tiezhu Yang <[email protected]>
---
arch/mips/kernel/signal.c | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
index c1632e8..5bce782 100644
--- a/arch/mips/kernel/signal.c
+++ b/arch/mips/kernel/signal.c
@@ -754,23 +754,25 @@ static int setup_rt_frame(void *sig_return, struct ksignal *ksig,
struct pt_regs *regs, sigset_t *set)
{
struct rt_sigframe __user *frame;
- int err = 0;

frame = get_sigframe(ksig, regs, sizeof(*frame));
if (!access_ok(frame, sizeof (*frame)))
return -EFAULT;

/* Create siginfo. */
- err |= copy_siginfo_to_user(&frame->rs_info, &ksig->info);
+ if (copy_siginfo_to_user(&frame->rs_info, &ksig->info))
+ return -EFAULT;

/* Create the ucontext. */
- err |= __put_user(0, &frame->rs_uc.uc_flags);
- err |= __put_user(NULL, &frame->rs_uc.uc_link);
- err |= __save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]);
- err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
- err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
-
- if (err)
+ if (__put_user(0, &frame->rs_uc.uc_flags))
+ return -EFAULT;
+ if (__put_user(NULL, &frame->rs_uc.uc_link))
+ return -EFAULT;
+ if (__save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]))
+ return -EFAULT;
+ if (setup_sigcontext(regs, &frame->rs_uc.uc_mcontext))
+ return -EFAULT;
+ if (__copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set)))
return -EFAULT;

/*
--
2.1.0

2022-01-02 13:33:01

by Thomas Bogendoerfer

Subject: Re: [PATCH v2 2/3] MIPS: signal: Return immediately if call fails

On Mon, Dec 20, 2021 at 12:27:39PM +0800, Tiezhu Yang wrote:
> When debug sigaltstack(), copy_siginfo_to_user() fails first in
> setup_rt_frame() if the alternate signal stack is too small, so
> it should return immediately if call fails, no need to call the
> following functions.
>
> Signed-off-by: Tiezhu Yang <[email protected]>
> ---
> arch/mips/kernel/signal.c | 20 +++++++++++---------
> 1 file changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
> index c1632e8..5bce782 100644
> --- a/arch/mips/kernel/signal.c
> +++ b/arch/mips/kernel/signal.c
> @@ -754,23 +754,25 @@ static int setup_rt_frame(void *sig_return, struct ksignal *ksig,
> struct pt_regs *regs, sigset_t *set)
> {
> struct rt_sigframe __user *frame;
> - int err = 0;
>
> frame = get_sigframe(ksig, regs, sizeof(*frame));
> if (!access_ok(frame, sizeof (*frame)))
> return -EFAULT;
>
> /* Create siginfo. */
> - err |= copy_siginfo_to_user(&frame->rs_info, &ksig->info);
> + if (copy_siginfo_to_user(&frame->rs_info, &ksig->info))
> + return -EFAULT;
>
> /* Create the ucontext. */
> - err |= __put_user(0, &frame->rs_uc.uc_flags);
> - err |= __put_user(NULL, &frame->rs_uc.uc_link);
> - err |= __save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]);
> - err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
> - err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
> -
> - if (err)
> + if (__put_user(0, &frame->rs_uc.uc_flags))
> + return -EFAULT;
> + if (__put_user(NULL, &frame->rs_uc.uc_link))
> + return -EFAULT;
> + if (__save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]))
> + return -EFAULT;
> + if (setup_sigcontext(regs, &frame->rs_uc.uc_mcontext))
> + return -EFAULT;
> + if (__copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set)))
> return -EFAULT;
>
> /*
> --
> 2.1.0

applied to mips-next.

Thomas.

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