On Thu, Nov 14, 2024 at 03:41:08PM -0800, Andrii Nakryiko wrote:

On Tue, Nov 5, 2024 at 5:34 AM Jiri Olsa [off-list ref] wrote:

quoted

Adding data argument to uprobe_write_opcode function and passing
it to newly added arch overloaded functions:

  arch_uprobe_verify_opcode
  arch_uprobe_is_register

This way each architecture can provide custmized verification.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 include/linux/uprobes.h |  6 +++++-
 kernel/events/uprobes.c | 25 +++++++++++++++++++------
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index 7d23a4fee6f4..be306028ed59 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h

@@ -182,7 +182,7 @@ extern bool is_trap_insn(uprobe_opcode_t *insn);
 extern unsigned long uprobe_get_swbp_addr(struct pt_regs *regs);
 extern unsigned long uprobe_get_trap_addr(struct pt_regs *regs);
 extern int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
-                              unsigned long vaddr, uprobe_opcode_t *insn, int len);
+                              unsigned long vaddr, uprobe_opcode_t *insn, int len, void *data);
 extern struct uprobe *uprobe_register(struct inode *inode, loff_t offset, loff_t ref_ctr_offset, struct uprobe_consumer *uc);
 extern int uprobe_apply(struct uprobe *uprobe, struct uprobe_consumer *uc, bool);
 extern void uprobe_unregister_nosync(struct uprobe *uprobe, struct uprobe_consumer *uc);

@@ -215,6 +215,10 @@ 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 page *page, unsigned long vaddr,
+                                    uprobe_opcode_t *new_opcode, void *data);
+extern bool arch_uprobe_is_register(uprobe_opcode_t *insn, int len, void *data);
 #else /* !CONFIG_UPROBES */
 struct uprobes_state {
 };

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 3e275717789b..944d9df1f081 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c

@@ -264,7 +264,13 @@ static void copy_to_page(struct page *page, unsigned long vaddr, const void *src
        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 len, void *data)
+{
+       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;

@@ -292,6 +298,12 @@ static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t
        return 1;
 }

+__weak int arch_uprobe_verify_opcode(struct page *page, unsigned long vaddr,
+                                    uprobe_opcode_t *new_opcode, void *data)

why wrapping lines? even original longer code was single line

hm, adding 'uprobe_opcode_t *new_opcode' would make the line over 100 chars,
but right, surrouding code is not strict ;-) ok

jirka

quoted

+{
+       return uprobe_verify_opcode(page, vaddr, new_opcode);
+}
+
 static struct delayed_uprobe *
 delayed_uprobe_check(struct uprobe *uprobe, struct mm_struct *mm)
 {

@@ -471,7 +483,8 @@ static int update_ref_ctr(struct uprobe *uprobe, struct mm_struct *mm,
  * Return 0 (success) or a negative errno.
  */
 int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
-                       unsigned long vaddr, uprobe_opcode_t *insn, int len)
+                       unsigned long vaddr, uprobe_opcode_t *insn, int len,
+                       void *data)
 {
        struct uprobe *uprobe;
        struct page *old_page, *new_page;

@@ -480,7 +493,7 @@ 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, len, data);
        uprobe = container_of(auprobe, struct uprobe, arch);

 retry:

@@ -491,7 +504,7 @@ 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(old_page, vaddr, insn, data);
        if (ret <= 0)
                goto put_old;

@@ -584,7 +597,7 @@ int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned
 {
        uprobe_opcode_t insn = UPROBE_SWBP_INSN;

-       return uprobe_write_opcode(auprobe, mm, vaddr, &insn, UPROBE_SWBP_INSN_SIZE);
+       return uprobe_write_opcode(auprobe, mm, vaddr, &insn, UPROBE_SWBP_INSN_SIZE, NULL);
 }

 /**

@@ -600,7 +613,7 @@ int __weak
 set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr)
 {
        return uprobe_write_opcode(auprobe, mm, vaddr,
-                       (uprobe_opcode_t *)&auprobe->insn, UPROBE_SWBP_INSN_SIZE);
+                       (uprobe_opcode_t *)&auprobe->insn, UPROBE_SWBP_INSN_SIZE, NULL);
 }

 /* uprobe should have guaranteed positive refcount */
--

2.47.0