riscv: Randomize lower bits of stack address

[PATCH] riscv: Randomize lower bits of stack address

Posted by Yunhui Cui 1 year, 5 months ago

Implement arch_align_stack() to randomize the lower bits
of the stack address.

Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
---
 arch/riscv/include/asm/exec.h | 8 ++++++++
 arch/riscv/kernel/process.c   | 9 +++++++++
 2 files changed, 17 insertions(+)
 create mode 100644 arch/riscv/include/asm/exec.h

diff --git a/arch/riscv/include/asm/exec.h b/arch/riscv/include/asm/exec.h
new file mode 100644
index 000000000000..07d9942682e0
--- /dev/null
+++ b/arch/riscv/include/asm/exec.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __ASM_EXEC_H
+#define __ASM_EXEC_H
+
+extern unsigned long arch_align_stack(unsigned long sp);
+
+#endif	/* __ASM_EXEC_H */
diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index e4bc61c4e58a..e3142d8a6e28 100644
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -15,6 +15,7 @@
 #include <linux/tick.h>
 #include <linux/ptrace.h>
 #include <linux/uaccess.h>
+#include <linux/personality.h>
 
 #include <asm/unistd.h>
 #include <asm/processor.h>
@@ -26,6 +27,7 @@
 #include <asm/cpuidle.h>
 #include <asm/vector.h>
 #include <asm/cpufeature.h>
+#include <asm/exec.h>
 
 #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK)
 #include <linux/stackprotector.h>
@@ -99,6 +101,13 @@ void show_regs(struct pt_regs *regs)
 		dump_backtrace(regs, NULL, KERN_DEFAULT);
 }
 
+unsigned long arch_align_stack(unsigned long sp)
+{
+	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
+		sp -= get_random_u32_below(PAGE_SIZE);
+	return sp & ~0xf;
+}
+
 #ifdef CONFIG_COMPAT
 static bool compat_mode_supported __read_mostly;
 
-- 
2.20.1

Re: [PATCH] riscv: Randomize lower bits of stack address

Posted by yunhui cui 1 year, 5 months ago

Add punit in the loop.


On Tue, Jun 25, 2024 at 11:05 AM Yunhui Cui <cuiyunhui@bytedance.com> wrote:
>
> Implement arch_align_stack() to randomize the lower bits
> of the stack address.
>
> Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> ---
>  arch/riscv/include/asm/exec.h | 8 ++++++++
>  arch/riscv/kernel/process.c   | 9 +++++++++
>  2 files changed, 17 insertions(+)
>  create mode 100644 arch/riscv/include/asm/exec.h
>
> diff --git a/arch/riscv/include/asm/exec.h b/arch/riscv/include/asm/exec.h
> new file mode 100644
> index 000000000000..07d9942682e0
> --- /dev/null
> +++ b/arch/riscv/include/asm/exec.h
> @@ -0,0 +1,8 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +
> +#ifndef __ASM_EXEC_H
> +#define __ASM_EXEC_H
> +
> +extern unsigned long arch_align_stack(unsigned long sp);
> +
> +#endif /* __ASM_EXEC_H */
> diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
> index e4bc61c4e58a..e3142d8a6e28 100644
> --- a/arch/riscv/kernel/process.c
> +++ b/arch/riscv/kernel/process.c
> @@ -15,6 +15,7 @@
>  #include <linux/tick.h>
>  #include <linux/ptrace.h>
>  #include <linux/uaccess.h>
> +#include <linux/personality.h>
>
>  #include <asm/unistd.h>
>  #include <asm/processor.h>
> @@ -26,6 +27,7 @@
>  #include <asm/cpuidle.h>
>  #include <asm/vector.h>
>  #include <asm/cpufeature.h>
> +#include <asm/exec.h>
>
>  #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK)
>  #include <linux/stackprotector.h>
> @@ -99,6 +101,13 @@ void show_regs(struct pt_regs *regs)
>                 dump_backtrace(regs, NULL, KERN_DEFAULT);
>  }
>
> +unsigned long arch_align_stack(unsigned long sp)
> +{
> +       if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
> +               sp -= get_random_u32_below(PAGE_SIZE);
> +       return sp & ~0xf;
> +}
> +
>  #ifdef CONFIG_COMPAT
>  static bool compat_mode_supported __read_mostly;
>
> --
> 2.20.1
>

Thanks,
Yunhui

Re: [PATCH] riscv: Randomize lower bits of stack address

Posted by yunhui cui 1 year, 4 months ago

A gentle ping, Any more comments on this patch?

On Thu, Jul 11, 2024 at 2:09 PM yunhui cui <cuiyunhui@bytedance.com> wrote:
>
> Add punit in the loop.
>
>
> On Tue, Jun 25, 2024 at 11:05 AM Yunhui Cui <cuiyunhui@bytedance.com> wrote:
> >
> > Implement arch_align_stack() to randomize the lower bits
> > of the stack address.
> >
> > Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> > ---
> >  arch/riscv/include/asm/exec.h | 8 ++++++++
> >  arch/riscv/kernel/process.c   | 9 +++++++++
> >  2 files changed, 17 insertions(+)
> >  create mode 100644 arch/riscv/include/asm/exec.h
> >
> > diff --git a/arch/riscv/include/asm/exec.h b/arch/riscv/include/asm/exec.h
> > new file mode 100644
> > index 000000000000..07d9942682e0
> > --- /dev/null
> > +++ b/arch/riscv/include/asm/exec.h
> > @@ -0,0 +1,8 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +
> > +#ifndef __ASM_EXEC_H
> > +#define __ASM_EXEC_H
> > +
> > +extern unsigned long arch_align_stack(unsigned long sp);
> > +
> > +#endif /* __ASM_EXEC_H */
> > diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
> > index e4bc61c4e58a..e3142d8a6e28 100644
> > --- a/arch/riscv/kernel/process.c
> > +++ b/arch/riscv/kernel/process.c
> > @@ -15,6 +15,7 @@
> >  #include <linux/tick.h>
> >  #include <linux/ptrace.h>
> >  #include <linux/uaccess.h>
> > +#include <linux/personality.h>
> >
> >  #include <asm/unistd.h>
> >  #include <asm/processor.h>
> > @@ -26,6 +27,7 @@
> >  #include <asm/cpuidle.h>
> >  #include <asm/vector.h>
> >  #include <asm/cpufeature.h>
> > +#include <asm/exec.h>
> >
> >  #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK)
> >  #include <linux/stackprotector.h>
> > @@ -99,6 +101,13 @@ void show_regs(struct pt_regs *regs)
> >                 dump_backtrace(regs, NULL, KERN_DEFAULT);
> >  }
> >
> > +unsigned long arch_align_stack(unsigned long sp)
> > +{
> > +       if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
> > +               sp -= get_random_u32_below(PAGE_SIZE);
> > +       return sp & ~0xf;
> > +}
> > +
> >  #ifdef CONFIG_COMPAT
> >  static bool compat_mode_supported __read_mostly;
> >
> > --
> > 2.20.1
> >
>
> Thanks,
> Yunhui

Thanks,
Yunhui

Re: [PATCH] riscv: Randomize lower bits of stack address

Posted by Alexandre Ghiti 1 year, 4 months ago

Hi Yunhui,

On Thu, Aug 15, 2024 at 4:08 AM yunhui cui <cuiyunhui@bytedance.com> wrote:
>
> A gentle ping, Any more comments on this patch?

I'm adding @Kees Cook  in cc in case he has any.

Thanks,

Alex

>
> On Thu, Jul 11, 2024 at 2:09 PM yunhui cui <cuiyunhui@bytedance.com> wrote:
> >
> > Add punit in the loop.
> >
> >
> > On Tue, Jun 25, 2024 at 11:05 AM Yunhui Cui <cuiyunhui@bytedance.com> wrote:
> > >
> > > Implement arch_align_stack() to randomize the lower bits
> > > of the stack address.
> > >
> > > Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
> > > ---
> > >  arch/riscv/include/asm/exec.h | 8 ++++++++
> > >  arch/riscv/kernel/process.c   | 9 +++++++++
> > >  2 files changed, 17 insertions(+)
> > >  create mode 100644 arch/riscv/include/asm/exec.h
> > >
> > > diff --git a/arch/riscv/include/asm/exec.h b/arch/riscv/include/asm/exec.h
> > > new file mode 100644
> > > index 000000000000..07d9942682e0
> > > --- /dev/null
> > > +++ b/arch/riscv/include/asm/exec.h
> > > @@ -0,0 +1,8 @@
> > > +/* SPDX-License-Identifier: GPL-2.0-only */
> > > +
> > > +#ifndef __ASM_EXEC_H
> > > +#define __ASM_EXEC_H
> > > +
> > > +extern unsigned long arch_align_stack(unsigned long sp);
> > > +
> > > +#endif /* __ASM_EXEC_H */
> > > diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
> > > index e4bc61c4e58a..e3142d8a6e28 100644
> > > --- a/arch/riscv/kernel/process.c
> > > +++ b/arch/riscv/kernel/process.c
> > > @@ -15,6 +15,7 @@
> > >  #include <linux/tick.h>
> > >  #include <linux/ptrace.h>
> > >  #include <linux/uaccess.h>
> > > +#include <linux/personality.h>
> > >
> > >  #include <asm/unistd.h>
> > >  #include <asm/processor.h>
> > > @@ -26,6 +27,7 @@
> > >  #include <asm/cpuidle.h>
> > >  #include <asm/vector.h>
> > >  #include <asm/cpufeature.h>
> > > +#include <asm/exec.h>
> > >
> > >  #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK)
> > >  #include <linux/stackprotector.h>
> > > @@ -99,6 +101,13 @@ void show_regs(struct pt_regs *regs)
> > >                 dump_backtrace(regs, NULL, KERN_DEFAULT);
> > >  }
> > >
> > > +unsigned long arch_align_stack(unsigned long sp)
> > > +{
> > > +       if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
> > > +               sp -= get_random_u32_below(PAGE_SIZE);
> > > +       return sp & ~0xf;
> > > +}
> > > +
> > >  #ifdef CONFIG_COMPAT
> > >  static bool compat_mode_supported __read_mostly;
> > >
> > > --
> > > 2.20.1
> > >
> >
> > Thanks,
> > Yunhui
>
> Thanks,
> Yunhui