The current interface copy_oldmem_page() passes user pointer without
__user annotation and hence does unnecessary user/kernel pointer
conversions during its implementation.
Implement the interface copy_oldmem_page_buf() to avoid this issue.
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: x86 <x86@xxxxxxxxxx>
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@xxxxxxx>
---
arch/x86/kernel/crash_dump_64.c | 44 +++++++++++++++------------------
1 file changed, 20 insertions(+), 24 deletions(-)
diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_64.c
index 99cd505628fa..7a6fa797260f 100644
--- a/arch/x86/kernel/crash_dump_64.c
+++ b/arch/x86/kernel/crash_dump_64.c
@@ -12,9 +12,9 @@
#include <linux/io.h>
#include <linux/cc_platform.h>
-static ssize_t __copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
- unsigned long offset, int userbuf,
- bool encrypted)
+static ssize_t __copy_oldmem_page(unsigned long pfn, char __user *ubuf,
+ char *kbuf, size_t csize,
+ unsigned long offset, bool encrypted)
{
void *vaddr;
@@ -29,13 +29,13 @@ static ssize_t __copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
if (!vaddr)
return -ENOMEM;
- if (userbuf) {
- if (copy_to_user((void __user *)buf, vaddr + offset, csize)) {
+ if (ubuf) {
+ if (copy_to_user(ubuf, vaddr + offset, csize)) {
iounmap((void __iomem *)vaddr);
return -EFAULT;
}
} else
- memcpy(buf, vaddr + offset, csize);
+ memcpy(kbuf, vaddr + offset, csize);
set_iounmap_nonlazy();
iounmap((void __iomem *)vaddr);
@@ -43,39 +43,35 @@ static ssize_t __copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
}
/**
- * copy_oldmem_page - copy one page of memory
+ * copy_oldmem_page_buf - copy one page of memory
* @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 the old kernel's memory. 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 the old kernel's memory into the buffer pointed either by
+ * @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)
{
- return __copy_oldmem_page(pfn, buf, csize, offset, userbuf, false);
+ return __copy_oldmem_page(pfn, ubuf, kbuf, csize, offset, false);
}
/**
- * copy_oldmem_page_encrypted - same as copy_oldmem_page() above but ioremap the
- * memory with the encryption mask set to accommodate kdump on SME-enabled
+ * copy_oldmem_page_encrypted - same as copy_oldmem_page_buf() above but ioremap
+ * the memory with the encryption mask set to accommodate kdump on SME-enabled
* machines.
*/
ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char __user *ubuf,
char *kbuf, size_t csize,
unsigned long offset)
{
- if (ubuf)
- return __copy_oldmem_page(pfn, (__force char *)ubuf, csize,
- offset, 1, true);
- else
- return __copy_oldmem_page(pfn, kbuf, csize,
- offset, 0, true);
+ return __copy_oldmem_page(pfn, ubuf, kbuf, csize, offset, true);
}
ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
--
2.17.1
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