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 <[email protected]> Cc: Rich Felker <[email protected]> CC: linux-sh <[email protected]> Signed-off-by: Amit Daniel Kachhap <[email protected]> --- 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 _______________________________________________ kexec mailing list [email protected] http://lists.infradead.org/mailman/listinfo/kexec
