The current interface copy_oldmem_page() passes user pointer without
__user annotation and hence does unnecessary user/kernel pointer
conversions during its implementation.
Use the interface copy_oldmem_page_buf() to avoid this issue.
Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
Cc: Rich Felker <dalias@xxxxxxxx>
CC: linux-sh <linux-sh@xxxxxxxxxxxxxxx>
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@xxxxxxx>
---
arch/sh/kernel/crash_dump.c | 25 +++++++++++++------------
1 file changed, 13 insertions(+), 12 deletions(-)
diff --git a/arch/sh/kernel/crash_dump.c b/arch/sh/kernel/crash_dump.c
index 5b41b59698c1..a80dedf1ace5 100644
--- a/arch/sh/kernel/crash_dump.c
+++ b/arch/sh/kernel/crash_dump.c
@@ -11,20 +11,21 @@
#include <linux/uaccess.h>
/**
- * copy_oldmem_page - copy one page from "oldmem"
+ * copy_oldmem_page_buf - copy one page from "oldmem"
* @pfn: page frame number to be copied
- * @buf: target memory address for the copy; this can be in kernel address
- * space or user address space (see @userbuf)
+ * @ubuf: target user memory pointer for the copy; use copy_to_user() if this
+ * pointer is not NULL
+ * @kbuf: target kernel memory pointer for the copy; use memcpy() if this
+ * pointer is not NULL
* @csize: number of bytes to copy
* @offset: offset in bytes into the page (based on pfn) to begin the copy
- * @userbuf: if set, @buf is in user address space, use copy_to_user(),
- * otherwise @buf is in kernel address space, use memcpy().
*
- * Copy a page from "oldmem". For this page, there is no pte mapped
- * in the current kernel. We stitch up a pte, similar to kmap_atomic.
+ * Copy a page from "oldmem" into the buffer pointed by either @ubuf or @kbuf.
+ * For this page, there is no pte mapped in the current kernel. We stitch up a
+ * pte, similar to kmap_atomic.
*/
-ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
- size_t csize, unsigned long offset, int userbuf)
+ssize_t copy_oldmem_page_buf(unsigned long pfn, char __user *ubuf, char *kbuf,
+ size_t csize, unsigned long offset)
{
void __iomem *vaddr;
@@ -33,13 +34,13 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
vaddr = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
- if (userbuf) {
- if (copy_to_user((void __user *)buf, (vaddr + offset), csize)) {
+ if (ubuf) {
+ if (copy_to_user(ubuf, (vaddr + offset), csize)) {
iounmap(vaddr);
return -EFAULT;
}
} else
- memcpy(buf, (vaddr + offset), csize);
+ memcpy(kbuf, (vaddr + offset), csize);
iounmap(vaddr);
return csize;
--
2.17.1
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