From 7ad9c9d27048547e96e4e3a13b5780ec6f81bb9f Mon Sep 17 00:00:00 2001 From: Takuya Yoshikawa Date: Thu, 27 May 2010 18:58:03 +0900 Subject: [PATCH] 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 Signed-off-by: Michael S. Tsirkin --- drivers/vhost/vhost.c | 51 ++++++++++++++++++++++++------------------- 1 file changed, 28 insertions(+), 23 deletions(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 44f123abb0f4..e36620272715 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -320,10 +320,8 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) { 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 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) 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 @@ static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp) 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 @@ static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp) 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 @@ static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp) 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 @@ static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp) 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 @@ static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp) 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 @@ static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp) 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 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, unsigned long arg) 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; -- 2.30.2