vhost: fix to check the return value of copy_to/from_user() correctly
copy_to/from_user() returns the number of bytes that could not be copied.
So we need to check if it is not zero, and in that case, we should return
the error number -EFAULT rather than directly return the return value from
copy_to/from_user().
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 44f123a..e366202 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -320,10 +320,8 @@
{
struct vhost_memory mem, *newmem, *oldmem;
unsigned long size = offsetof(struct vhost_memory, regions);
- long r;
- r = copy_from_user(&mem, m, size);
- if (r)
- return r;
+ if (copy_from_user(&mem, m, size))
+ return -EFAULT;
if (mem.padding)
return -EOPNOTSUPP;
if (mem.nregions > VHOST_MEMORY_MAX_NREGIONS)
@@ -333,11 +331,10 @@
return -ENOMEM;
memcpy(newmem, &mem, size);
- r = copy_from_user(newmem->regions, m->regions,
- mem.nregions * sizeof *m->regions);
- if (r) {
+ if (copy_from_user(newmem->regions, m->regions,
+ mem.nregions * sizeof *m->regions)) {
kfree(newmem);
- return r;
+ return -EFAULT;
}
if (!memory_access_ok(d, newmem, vhost_has_feature(d, VHOST_F_LOG_ALL)))
@@ -389,9 +386,10 @@
r = -EBUSY;
break;
}
- r = copy_from_user(&s, argp, sizeof s);
- if (r < 0)
+ if (copy_from_user(&s, argp, sizeof s)) {
+ r = -EFAULT;
break;
+ }
if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) {
r = -EINVAL;
break;
@@ -405,9 +403,10 @@
r = -EBUSY;
break;
}
- r = copy_from_user(&s, argp, sizeof s);
- if (r < 0)
+ if (copy_from_user(&s, argp, sizeof s)) {
+ r = -EFAULT;
break;
+ }
if (s.num > 0xffff) {
r = -EINVAL;
break;
@@ -419,12 +418,14 @@
case VHOST_GET_VRING_BASE:
s.index = idx;
s.num = vq->last_avail_idx;
- r = copy_to_user(argp, &s, sizeof s);
+ if (copy_to_user(argp, &s, sizeof s))
+ r = -EFAULT;
break;
case VHOST_SET_VRING_ADDR:
- r = copy_from_user(&a, argp, sizeof a);
- if (r < 0)
+ if (copy_from_user(&a, argp, sizeof a)) {
+ r = -EFAULT;
break;
+ }
if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) {
r = -EOPNOTSUPP;
break;
@@ -477,9 +478,10 @@
vq->used = (void __user *)(unsigned long)a.used_user_addr;
break;
case VHOST_SET_VRING_KICK:
- r = copy_from_user(&f, argp, sizeof f);
- if (r < 0)
+ if (copy_from_user(&f, argp, sizeof f)) {
+ r = -EFAULT;
break;
+ }
eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
if (IS_ERR(eventfp)) {
r = PTR_ERR(eventfp);
@@ -492,9 +494,10 @@
filep = eventfp;
break;
case VHOST_SET_VRING_CALL:
- r = copy_from_user(&f, argp, sizeof f);
- if (r < 0)
+ if (copy_from_user(&f, argp, sizeof f)) {
+ r = -EFAULT;
break;
+ }
eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
if (IS_ERR(eventfp)) {
r = PTR_ERR(eventfp);
@@ -510,9 +513,10 @@
filep = eventfp;
break;
case VHOST_SET_VRING_ERR:
- r = copy_from_user(&f, argp, sizeof f);
- if (r < 0)
+ if (copy_from_user(&f, argp, sizeof f)) {
+ r = -EFAULT;
break;
+ }
eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
if (IS_ERR(eventfp)) {
r = PTR_ERR(eventfp);
@@ -575,9 +579,10 @@
r = vhost_set_memory(d, argp);
break;
case VHOST_SET_LOG_BASE:
- r = copy_from_user(&p, argp, sizeof p);
- if (r < 0)
+ if (copy_from_user(&p, argp, sizeof p)) {
+ r = -EFAULT;
break;
+ }
if ((u64)(unsigned long)p != p) {
r = -EFAULT;
break;
