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 <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Dave Hansen <[email protected]> Cc: x86 <[email protected]> Signed-off-by: Amit Daniel Kachhap <[email protected]> --- 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 _______________________________________________ kexec mailing list [email protected] http://lists.infradead.org/mailman/listinfo/kexec
