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[1/2] um: add uml_kmalloc_array() helper to avoid potential

Message ID 20260120112938.463596-1-iamhswang@gmail.com
State Changes Requested
Headers show
Series [1/2] um: add uml_kmalloc_array() helper to avoid potential | expand

Commit Message

iamhswang@gmail.com Jan. 20, 2026, 11:28 a.m. UTC 
From: Haisu Wang <iamhswang@gmail.com>

Add uml_kmalloc_array to avoid potential dynamic multiplication
overflow. Since in Documentation/process/deprecated.rst,
the preferred way is avoid the open-coded arithmetic.

Signed-off-by: Haisu Wang <wanghs18@chinatelecom.cn>
---
 arch/um/include/shared/um_malloc.h | 1 +
 arch/um/kernel/mem.c               | 5 +++++
 2 files changed, 6 insertions(+)

Comments

Johannes Berg July 22, 2026, 2:49 p.m. UTC | #1 
On Tue, 2026-01-20 at 19:28 +0800, iamhswang@gmail.com wrote:
> From: Haisu Wang <iamhswang@gmail.com>
> 
> Add uml_kmalloc_array to avoid potential dynamic multiplication
> overflow. Since in Documentation/process/deprecated.rst,
> the preferred way is avoid the open-coded arithmetic.

Personally, I think it's kind of pointless because the only two users
have small static arguments ... but if you want to continue with this
then
> 
> +extern void *uml_kmalloc_array(int count, int size, int flags);

the prototype should probably match better and use size_t, size_t,
unsigned int?

johannes
diff mbox series

Patch

diff --git a/arch/um/include/shared/um_malloc.h b/arch/um/include/shared/um_malloc.h
index 815dd03e8707..a55a81131e10 100644
--- a/arch/um/include/shared/um_malloc.h
+++ b/arch/um/include/shared/um_malloc.h
@@ -9,6 +9,7 @@ 
 #include <generated/asm-offsets.h>
 
 extern void *uml_kmalloc(int size, int flags);
+extern void *uml_kmalloc_array(int count, int size, int flags);
 extern void kfree(const void *ptr);
 
 extern void *vmalloc_noprof(unsigned long size);
diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
index 39c4a7e21c6f..3bf9e9bef3bf 100644
--- a/arch/um/kernel/mem.c
+++ b/arch/um/kernel/mem.c
@@ -126,6 +126,11 @@  void *uml_kmalloc(int size, int flags)
 	return kmalloc(size, flags);
 }
 
+void *uml_kmalloc_array(int count, int size, int flags)
+{
+	return kmalloc_array(count, size, flags);
+}
+
 static const pgprot_t protection_map[16] = {
 	[VM_NONE]					= PAGE_NONE,
 	[VM_READ]					= PAGE_READONLY,