[Xen-devel] [PATCH] linux/privcmd: fix for proper operation in compat mode

["Jan Beulich" <JBeulich@xxxxxxxxxx>]

- sizeof(struct privcmd_mmapbatch_32) was wrong
- MFN array must be translated for IOCTL_PRIVCMD_MMAPBATCH

Also, the error indicator of IOCTL_PRIVCMD_MMAPBATCH should be in the
top nibble (it is documented that way in include/xen/public/privcmd.h
and include/xen/compat_ioctl.h), but since that is an incompatible
change it is not being done here (instead, a new ioctl with proper
behavior will need to be added).

As usual, written against 2.6.32.2 and made apply to the 2.6.18
tree without further testing.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

--- head-2010-01-04.orig/drivers/xen/privcmd/compat_privcmd.c   2009-11-06 
10:45:48.000000000 +0100
+++ head-2010-01-04/drivers/xen/privcmd/compat_privcmd.c        2010-01-04 
13:50:00.000000000 +0100
@@ -51,17 +51,49 @@ int privcmd_ioctl_32(int fd, unsigned in
                struct privcmd_mmapbatch *p;
                struct privcmd_mmapbatch_32 *p32;
                struct privcmd_mmapbatch_32 n32;
+#ifdef xen_pfn32_t
+               xen_pfn_t *__user arr;
+               xen_pfn32_t *__user arr32;
+               unsigned int i;
+#endif
 
                p32 = compat_ptr(arg);
                p = compat_alloc_user_space(sizeof(*p));
                if (copy_from_user(&n32, p32, sizeof(n32)) ||
                    put_user(n32.num, &p->num) ||
                    put_user(n32.dom, &p->dom) ||
-                   put_user(n32.addr, &p->addr) ||
-                   put_user(compat_ptr(n32.arr), &p->arr))
+                   put_user(n32.addr, &p->addr))
                        return -EFAULT;
+#ifdef xen_pfn32_t
+               arr = compat_alloc_user_space(n32.num * sizeof(*arr)
+                                             + sizeof(*p));
+               arr32 = compat_ptr(n32.arr);
+               for (i = 0; i < n32.num; ++i) {
+                       xen_pfn32_t mfn;
+
+                       if (get_user(mfn, arr32 + i) || put_user(mfn, arr + i))
+                               return -EFAULT;
+               }
+
+               if (put_user(arr, &p->arr))
+                       return -EFAULT;
+#else
+               if (put_user(compat_ptr(n32.arr), &p->arr))
+                       return -EFAULT;
+#endif
                
                ret = sys_ioctl(fd, IOCTL_PRIVCMD_MMAPBATCH, (unsigned long)p);
+
+#ifdef xen_pfn32_t
+               for (i = 0; !ret && i < n32.num; ++i) {
+                       xen_pfn_t mfn;
+
+                       if (get_user(mfn, arr + i) || put_user(mfn, arr32 + i))
+                               ret = -EFAULT;
+                       else if (mfn != (xen_pfn32_t)mfn)
+                               ret = -ERANGE;
+               }
+#endif
        }
                break;
        default:
--- head-2010-01-04.orig/include/xen/compat_ioctl.h     2007-07-10 
09:42:30.000000000 +0200
+++ head-2010-01-04/include/xen/compat_ioctl.h  2009-12-17 15:40:40.000000000 
+0100
@@ -23,6 +23,11 @@
 #define __LINUX_XEN_COMPAT_H__ 
 
 #include <linux/compat.h>
+#include <linux/compiler.h>
+
+#if defined(CONFIG_X86) || defined(CONFIG_IA64)
+#define xen_pfn32_t __u32
+#endif
 
 extern int privcmd_ioctl_32(int fd, unsigned int cmd, unsigned long arg);
 struct privcmd_mmap_32 {
@@ -34,7 +39,14 @@ struct privcmd_mmap_32 {
 struct privcmd_mmapbatch_32 {
        int num;     /* number of pages to populate */
        domid_t dom; /* target domain */
+#if defined(CONFIG_X86) || defined(CONFIG_IA64)
+       union {      /* virtual address */
+               __u64 addr __packed;
+               __u32 va;
+       };
+#else
        __u64 addr;  /* virtual address */
+#endif
        compat_uptr_t arr; /* array of mfns - top nibble set on err */
 };
 #define IOCTL_PRIVCMD_MMAP_32                   \

Attachment: xenlinux-privcmd-compat.patch
Description: Text document

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