[PATCH 2/7] modules: Add within_module_text() macro

From: Christophe Leroy
Date: Mon Jan 24 2022 - 04:22:42 EST


Add a macro to check whether an address is within module's text.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
include/linux/module.h | 13 +++++++++++++
kernel/module.c | 17 +++++------------
2 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index 33b4db8f5ca5..fc7adb110a81 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -570,6 +570,19 @@ static inline bool within_range(unsigned long addr, void *base, unsigned int siz
return addr >= (unsigned long)base && addr < (unsigned long)base + size;
}

+static inline bool within_module_layout_text(unsigned long addr,
+ const struct module_layout *layout)
+{
+ return within_range(addr, layout->base, layout->text_size);
+}
+
+static inline bool within_module_text(unsigned long addr,
+ const struct module *mod)
+{
+ return within_module_layout_text(addr, &mod->core_layout) ||
+ within_module_layout_text(addr, &mod->init_layout);
+}
+
static inline bool within_module_layout(unsigned long addr,
const struct module_layout *layout)
{
diff --git a/kernel/module.c b/kernel/module.c
index 84a9141a5e15..201d27643c84 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -4224,11 +4224,6 @@ SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
return load_module(&info, uargs, flags);
}

-static inline int within(unsigned long addr, void *start, unsigned long size)
-{
- return ((void *)addr >= start && (void *)addr < start + size);
-}
-
#ifdef CONFIG_KALLSYMS
/*
* This ignores the intensely annoying "mapping symbols" found
@@ -4765,13 +4760,11 @@ bool is_module_text_address(unsigned long addr)
struct module *__module_text_address(unsigned long addr)
{
struct module *mod = __module_address(addr);
- if (mod) {
- /* Make sure it's within the text section. */
- if (!within(addr, mod->init_layout.base, mod->init_layout.text_size)
- && !within(addr, mod->core_layout.base, mod->core_layout.text_size))
- mod = NULL;
- }
- return mod;
+
+ if (mod && within_module_text(addr, mod))
+ return mod;
+
+ return NULL;
}

/* Don't grab lock, we're oopsing. */
--
2.33.1