Adding arch_uprobe_verify_opcode function, so we can overload
verification for each architecture in following changes.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 include/linux/uprobes.h |  5 +++++
 kernel/events/uprobes.c | 19 ++++++++++++++++---
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index cc723bc48c1d..8843b7f99ed0 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -215,6 +215,11 @@ extern void uprobe_handle_trampoline(struct pt_regs *regs);
 extern void *arch_uretprobe_trampoline(unsigned long *psize);
 extern unsigned long uprobe_get_trampoline_vaddr(void);
 extern void uprobe_copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len);
+extern int uprobe_verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode);
+extern int arch_uprobe_verify_opcode(struct arch_uprobe *auprobe, struct page *page,
+				     unsigned long vaddr, uprobe_opcode_t *new_opcode,
+				     int nbytes);
+extern bool arch_uprobe_is_register(uprobe_opcode_t *insn, int nbytes);
 #else /* !CONFIG_UPROBES */
 struct uprobes_state {
 };
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 7c2ecf11a573..8068f91de9e3 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -263,7 +263,13 @@ static void uprobe_copy_to_page(struct page *page, unsigned long vaddr, const vo
 	kunmap_atomic(kaddr);
 }
 
-static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode)
+__weak bool arch_uprobe_is_register(uprobe_opcode_t *insn, int nbytes)
+{
+	return is_swbp_insn(insn);
+}
+
+int uprobe_verify_opcode(struct page *page, unsigned long vaddr,
+			 uprobe_opcode_t *new_opcode)
 {
 	uprobe_opcode_t old_opcode;
 	bool is_swbp;
@@ -291,6 +297,13 @@ static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t
 	return 1;
 }
 
+__weak int arch_uprobe_verify_opcode(struct arch_uprobe *auprobe, struct page *page,
+				     unsigned long vaddr, uprobe_opcode_t *new_opcode,
+				     int nbytes)
+{
+	return uprobe_verify_opcode(page, vaddr, new_opcode);
+}
+
 static struct delayed_uprobe *
 delayed_uprobe_check(struct uprobe *uprobe, struct mm_struct *mm)
 {
@@ -479,7 +492,7 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
 	bool orig_page_huge = false;
 	unsigned int gup_flags = FOLL_FORCE;
 
-	is_register = is_swbp_insn(insn);
+	is_register = arch_uprobe_is_register(insn, nbytes);
 	uprobe = container_of(auprobe, struct uprobe, arch);
 
 retry:
@@ -490,7 +503,7 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
 	if (IS_ERR(old_page))
 		return PTR_ERR(old_page);
 
-	ret = verify_opcode(old_page, vaddr, insn);
+	ret = arch_uprobe_verify_opcode(auprobe, old_page, vaddr, insn, nbytes);
 	if (ret <= 0)
 		goto put_old;
 
-- 
2.47.0

On Wed, Dec 11, 2024 at 5:34 AM Jiri Olsa <jolsa@kernel.org> wrote:
>
> Adding arch_uprobe_verify_opcode function, so we can overload
> verification for each architecture in following changes.
>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
>  include/linux/uprobes.h |  5 +++++
>  kernel/events/uprobes.c | 19 ++++++++++++++++---
>  2 files changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
> index cc723bc48c1d..8843b7f99ed0 100644
> --- a/include/linux/uprobes.h
> +++ b/include/linux/uprobes.h
> @@ -215,6 +215,11 @@ extern void uprobe_handle_trampoline(struct pt_regs *regs);
>  extern void *arch_uretprobe_trampoline(unsigned long *psize);
>  extern unsigned long uprobe_get_trampoline_vaddr(void);
>  extern void uprobe_copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len);
> +extern int uprobe_verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode);
> +extern int arch_uprobe_verify_opcode(struct arch_uprobe *auprobe, struct page *page,
> +                                    unsigned long vaddr, uprobe_opcode_t *new_opcode,
> +                                    int nbytes);
> +extern bool arch_uprobe_is_register(uprobe_opcode_t *insn, int nbytes);
>  #else /* !CONFIG_UPROBES */
>  struct uprobes_state {
>  };
> diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> index 7c2ecf11a573..8068f91de9e3 100644
> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -263,7 +263,13 @@ static void uprobe_copy_to_page(struct page *page, unsigned long vaddr, const vo
>         kunmap_atomic(kaddr);
>  }
>
> -static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode)
> +__weak bool arch_uprobe_is_register(uprobe_opcode_t *insn, int nbytes)
> +{
> +       return is_swbp_insn(insn);

a bit weird that we ignore nbytes here... should we have nbytes ==
UPROBE_SWBP_INSN_SIZE check somewhere here or inside is_swbp_insn()?

> +}
> +
> +int uprobe_verify_opcode(struct page *page, unsigned long vaddr,
> +                        uprobe_opcode_t *new_opcode)
>  {
>         uprobe_opcode_t old_opcode;
>         bool is_swbp;
> @@ -291,6 +297,13 @@ static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t
>         return 1;
>  }
>
> +__weak int arch_uprobe_verify_opcode(struct arch_uprobe *auprobe, struct page *page,
> +                                    unsigned long vaddr, uprobe_opcode_t *new_opcode,
> +                                    int nbytes)
> +{
> +       return uprobe_verify_opcode(page, vaddr, new_opcode);

again, dropping nbytes on the floor here

> +}
> +
>  static struct delayed_uprobe *
>  delayed_uprobe_check(struct uprobe *uprobe, struct mm_struct *mm)
>  {
> @@ -479,7 +492,7 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
>         bool orig_page_huge = false;
>         unsigned int gup_flags = FOLL_FORCE;
>
> -       is_register = is_swbp_insn(insn);
> +       is_register = arch_uprobe_is_register(insn, nbytes);
>         uprobe = container_of(auprobe, struct uprobe, arch);
>
>  retry:
> @@ -490,7 +503,7 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
>         if (IS_ERR(old_page))
>                 return PTR_ERR(old_page);
>
> -       ret = verify_opcode(old_page, vaddr, insn);
> +       ret = arch_uprobe_verify_opcode(auprobe, old_page, vaddr, insn, nbytes);
>         if (ret <= 0)
>                 goto put_old;
>
> --
> 2.47.0
>

On Thu, Dec 12, 2024 at 04:48:05PM -0800, Andrii Nakryiko wrote:
> On Wed, Dec 11, 2024 at 5:34 AM Jiri Olsa <jolsa@kernel.org> wrote:
> >
> > Adding arch_uprobe_verify_opcode function, so we can overload
> > verification for each architecture in following changes.
> >
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> >  include/linux/uprobes.h |  5 +++++
> >  kernel/events/uprobes.c | 19 ++++++++++++++++---
> >  2 files changed, 21 insertions(+), 3 deletions(-)
> >
> > diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
> > index cc723bc48c1d..8843b7f99ed0 100644
> > --- a/include/linux/uprobes.h
> > +++ b/include/linux/uprobes.h
> > @@ -215,6 +215,11 @@ extern void uprobe_handle_trampoline(struct pt_regs *regs);
> >  extern void *arch_uretprobe_trampoline(unsigned long *psize);
> >  extern unsigned long uprobe_get_trampoline_vaddr(void);
> >  extern void uprobe_copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len);
> > +extern int uprobe_verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode);
> > +extern int arch_uprobe_verify_opcode(struct arch_uprobe *auprobe, struct page *page,
> > +                                    unsigned long vaddr, uprobe_opcode_t *new_opcode,
> > +                                    int nbytes);
> > +extern bool arch_uprobe_is_register(uprobe_opcode_t *insn, int nbytes);
> >  #else /* !CONFIG_UPROBES */
> >  struct uprobes_state {
> >  };
> > diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> > index 7c2ecf11a573..8068f91de9e3 100644
> > --- a/kernel/events/uprobes.c
> > +++ b/kernel/events/uprobes.c
> > @@ -263,7 +263,13 @@ static void uprobe_copy_to_page(struct page *page, unsigned long vaddr, const vo
> >         kunmap_atomic(kaddr);
> >  }
> >
> > -static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode)
> > +__weak bool arch_uprobe_is_register(uprobe_opcode_t *insn, int nbytes)
> > +{
> > +       return is_swbp_insn(insn);
> 
> a bit weird that we ignore nbytes here... should we have nbytes ==
> UPROBE_SWBP_INSN_SIZE check somewhere here or inside is_swbp_insn()?

the original is_swbp_insn function does not need that and we need
nbytes in the overloaded arch_uprobe_is_register to distinguish
between 1 byte and 5 byte update..

jirka

> 
> > +}
> > +
> > +int uprobe_verify_opcode(struct page *page, unsigned long vaddr,
> > +                        uprobe_opcode_t *new_opcode)
> >  {
> >         uprobe_opcode_t old_opcode;
> >         bool is_swbp;
> > @@ -291,6 +297,13 @@ static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t
> >         return 1;
> >  }
> >
> > +__weak int arch_uprobe_verify_opcode(struct arch_uprobe *auprobe, struct page *page,
> > +                                    unsigned long vaddr, uprobe_opcode_t *new_opcode,
> > +                                    int nbytes)
> > +{
> > +       return uprobe_verify_opcode(page, vaddr, new_opcode);
> 
> again, dropping nbytes on the floor here
> 
> > +}
> > +
> >  static struct delayed_uprobe *
> >  delayed_uprobe_check(struct uprobe *uprobe, struct mm_struct *mm)
> >  {
> > @@ -479,7 +492,7 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
> >         bool orig_page_huge = false;
> >         unsigned int gup_flags = FOLL_FORCE;
> >
> > -       is_register = is_swbp_insn(insn);
> > +       is_register = arch_uprobe_is_register(insn, nbytes);
> >         uprobe = container_of(auprobe, struct uprobe, arch);
> >
> >  retry:
> > @@ -490,7 +503,7 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
> >         if (IS_ERR(old_page))
> >                 return PTR_ERR(old_page);
> >
> > -       ret = verify_opcode(old_page, vaddr, insn);
> > +       ret = arch_uprobe_verify_opcode(auprobe, old_page, vaddr, insn, nbytes);
> >         if (ret <= 0)
> >                 goto put_old;
> >
> > --
> > 2.47.0
> >

On Fri, Dec 13, 2024 at 5:21 AM Jiri Olsa <olsajiri@gmail.com> wrote:
>
> On Thu, Dec 12, 2024 at 04:48:05PM -0800, Andrii Nakryiko wrote:
> > On Wed, Dec 11, 2024 at 5:34 AM Jiri Olsa <jolsa@kernel.org> wrote:
> > >
> > > Adding arch_uprobe_verify_opcode function, so we can overload
> > > verification for each architecture in following changes.
> > >
> > > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > > ---
> > >  include/linux/uprobes.h |  5 +++++
> > >  kernel/events/uprobes.c | 19 ++++++++++++++++---
> > >  2 files changed, 21 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
> > > index cc723bc48c1d..8843b7f99ed0 100644
> > > --- a/include/linux/uprobes.h
> > > +++ b/include/linux/uprobes.h
> > > @@ -215,6 +215,11 @@ extern void uprobe_handle_trampoline(struct pt_regs *regs);
> > >  extern void *arch_uretprobe_trampoline(unsigned long *psize);
> > >  extern unsigned long uprobe_get_trampoline_vaddr(void);
> > >  extern void uprobe_copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len);
> > > +extern int uprobe_verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode);
> > > +extern int arch_uprobe_verify_opcode(struct arch_uprobe *auprobe, struct page *page,
> > > +                                    unsigned long vaddr, uprobe_opcode_t *new_opcode,
> > > +                                    int nbytes);
> > > +extern bool arch_uprobe_is_register(uprobe_opcode_t *insn, int nbytes);
> > >  #else /* !CONFIG_UPROBES */
> > >  struct uprobes_state {
> > >  };
> > > diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> > > index 7c2ecf11a573..8068f91de9e3 100644
> > > --- a/kernel/events/uprobes.c
> > > +++ b/kernel/events/uprobes.c
> > > @@ -263,7 +263,13 @@ static void uprobe_copy_to_page(struct page *page, unsigned long vaddr, const vo
> > >         kunmap_atomic(kaddr);
> > >  }
> > >
> > > -static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode)
> > > +__weak bool arch_uprobe_is_register(uprobe_opcode_t *insn, int nbytes)
> > > +{
> > > +       return is_swbp_insn(insn);
> >
> > a bit weird that we ignore nbytes here... should we have nbytes ==
> > UPROBE_SWBP_INSN_SIZE check somewhere here or inside is_swbp_insn()?
>
> the original is_swbp_insn function does not need that and we need
> nbytes in the overloaded arch_uprobe_is_register to distinguish
> between 1 byte and 5 byte update..
>

and that's my point, if some architecture forgot to override it for
nop5 (or similar stuff), this default implementation should reject
instruction that's not an original nop, no?


> jirka
>
> >
> > > +}
> > > +
> > > +int uprobe_verify_opcode(struct page *page, unsigned long vaddr,
> > > +                        uprobe_opcode_t *new_opcode)
> > >  {
> > >         uprobe_opcode_t old_opcode;
> > >         bool is_swbp;
> > > @@ -291,6 +297,13 @@ static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t
> > >         return 1;
> > >  }
> > >
> > > +__weak int arch_uprobe_verify_opcode(struct arch_uprobe *auprobe, struct page *page,
> > > +                                    unsigned long vaddr, uprobe_opcode_t *new_opcode,
> > > +                                    int nbytes)
> > > +{
> > > +       return uprobe_verify_opcode(page, vaddr, new_opcode);
> >
> > again, dropping nbytes on the floor here
> >
> > > +}
> > > +
> > >  static struct delayed_uprobe *
> > >  delayed_uprobe_check(struct uprobe *uprobe, struct mm_struct *mm)
> > >  {
> > > @@ -479,7 +492,7 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
> > >         bool orig_page_huge = false;
> > >         unsigned int gup_flags = FOLL_FORCE;
> > >
> > > -       is_register = is_swbp_insn(insn);
> > > +       is_register = arch_uprobe_is_register(insn, nbytes);
> > >         uprobe = container_of(auprobe, struct uprobe, arch);
> > >
> > >  retry:
> > > @@ -490,7 +503,7 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
> > >         if (IS_ERR(old_page))
> > >                 return PTR_ERR(old_page);
> > >
> > > -       ret = verify_opcode(old_page, vaddr, insn);
> > > +       ret = arch_uprobe_verify_opcode(auprobe, old_page, vaddr, insn, nbytes);
> > >         if (ret <= 0)
> > >                 goto put_old;
> > >
> > > --
> > > 2.47.0
> > >

On Fri, Dec 13, 2024 at 01:11:30PM -0800, Andrii Nakryiko wrote:
> On Fri, Dec 13, 2024 at 5:21 AM Jiri Olsa <olsajiri@gmail.com> wrote:
> >
> > On Thu, Dec 12, 2024 at 04:48:05PM -0800, Andrii Nakryiko wrote:
> > > On Wed, Dec 11, 2024 at 5:34 AM Jiri Olsa <jolsa@kernel.org> wrote:
> > > >
> > > > Adding arch_uprobe_verify_opcode function, so we can overload
> > > > verification for each architecture in following changes.
> > > >
> > > > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > > > ---
> > > >  include/linux/uprobes.h |  5 +++++
> > > >  kernel/events/uprobes.c | 19 ++++++++++++++++---
> > > >  2 files changed, 21 insertions(+), 3 deletions(-)
> > > >
> > > > diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
> > > > index cc723bc48c1d..8843b7f99ed0 100644
> > > > --- a/include/linux/uprobes.h
> > > > +++ b/include/linux/uprobes.h
> > > > @@ -215,6 +215,11 @@ extern void uprobe_handle_trampoline(struct pt_regs *regs);
> > > >  extern void *arch_uretprobe_trampoline(unsigned long *psize);
> > > >  extern unsigned long uprobe_get_trampoline_vaddr(void);
> > > >  extern void uprobe_copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len);
> > > > +extern int uprobe_verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode);
> > > > +extern int arch_uprobe_verify_opcode(struct arch_uprobe *auprobe, struct page *page,
> > > > +                                    unsigned long vaddr, uprobe_opcode_t *new_opcode,
> > > > +                                    int nbytes);
> > > > +extern bool arch_uprobe_is_register(uprobe_opcode_t *insn, int nbytes);
> > > >  #else /* !CONFIG_UPROBES */
> > > >  struct uprobes_state {
> > > >  };
> > > > diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> > > > index 7c2ecf11a573..8068f91de9e3 100644
> > > > --- a/kernel/events/uprobes.c
> > > > +++ b/kernel/events/uprobes.c
> > > > @@ -263,7 +263,13 @@ static void uprobe_copy_to_page(struct page *page, unsigned long vaddr, const vo
> > > >         kunmap_atomic(kaddr);
> > > >  }
> > > >
> > > > -static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode)
> > > > +__weak bool arch_uprobe_is_register(uprobe_opcode_t *insn, int nbytes)
> > > > +{
> > > > +       return is_swbp_insn(insn);
> > >
> > > a bit weird that we ignore nbytes here... should we have nbytes ==
> > > UPROBE_SWBP_INSN_SIZE check somewhere here or inside is_swbp_insn()?
> >
> > the original is_swbp_insn function does not need that and we need
> > nbytes in the overloaded arch_uprobe_is_register to distinguish
> > between 1 byte and 5 byte update..
> >
> 
> and that's my point, if some architecture forgot to override it for
> nop5 (or similar stuff), this default implementation should reject
> instruction that's not an original nop, no?

ok, makes sense, will add that

thanks,
jirka