| Message ID | 20211207114835.GA31153@kili (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3] vduse: vduse: check that offsets are within bounds | expand |
On Tue, Dec 7, 2021 at 7:49 PM Dan Carpenter <dan.carpenter@oracle.com> wrote: > > In vduse_dev_ioctl(), the "config.offset" comes from the user. There > needs to a check to prevent it being out of bounds. The "config.offset" > and "dev->config_size" variables are both type u32. So if the offset is > out of bounds then the "dev->config_size - config.offset" subtraction > results in a very high u32 value. > > The vhost_vdpa_config_validate() function has a similar issue, but there > the "size" is long type so the subtraction works on 64bit system and > this change only affects 32bit systems. > > Fixes: c8a6153b6c59 ("vduse: Introduce VDUSE - vDPA Device in Userspace") > Fixes: 4c8cf31885f6 ("vhost: introduce vDPA-based backend") > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Stable candidate. Patch looks good to me but I think we need to use separate patches to ease the backporting. Thanks > --- > v2: the first version had a reversed if statement > v3: fix vhost_vdpa_config_validate() as pointed out by Yongji Xie. > > drivers/vdpa/vdpa_user/vduse_dev.c | 3 ++- > drivers/vhost/vdpa.c | 2 +- > 2 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c > index c9204c62f339..1a206f95d73a 100644 > --- a/drivers/vdpa/vdpa_user/vduse_dev.c > +++ b/drivers/vdpa/vdpa_user/vduse_dev.c > @@ -975,7 +975,8 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd, > break; > > ret = -EINVAL; > - if (config.length == 0 || > + if (config.offset > dev->config_size || > + config.length == 0 || > config.length > dev->config_size - config.offset) > break; > > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c > index 29cced1cd277..e3c4f059b21a 100644 > --- a/drivers/vhost/vdpa.c > +++ b/drivers/vhost/vdpa.c > @@ -197,7 +197,7 @@ static int vhost_vdpa_config_validate(struct vhost_vdpa *v, > struct vdpa_device *vdpa = v->vdpa; > long size = vdpa->config->get_config_size(vdpa); > > - if (c->len == 0) > + if (c->len == 0 || c->off > size) > return -EINVAL; > > if (c->len > size - c->off) > -- > 2.20.1 >
diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c index c9204c62f339..1a206f95d73a 100644 --- a/drivers/vdpa/vdpa_user/vduse_dev.c +++ b/drivers/vdpa/vdpa_user/vduse_dev.c @@ -975,7 +975,8 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd, break; ret = -EINVAL; - if (config.length == 0 || + if (config.offset > dev->config_size || + config.length == 0 || config.length > dev->config_size - config.offset) break; diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c index 29cced1cd277..e3c4f059b21a 100644 --- a/drivers/vhost/vdpa.c +++ b/drivers/vhost/vdpa.c @@ -197,7 +197,7 @@ static int vhost_vdpa_config_validate(struct vhost_vdpa *v, struct vdpa_device *vdpa = v->vdpa; long size = vdpa->config->get_config_size(vdpa); - if (c->len == 0) + if (c->len == 0 || c->off > size) return -EINVAL; if (c->len > size - c->off)
In vduse_dev_ioctl(), the "config.offset" comes from the user. There needs to a check to prevent it being out of bounds. The "config.offset" and "dev->config_size" variables are both type u32. So if the offset is out of bounds then the "dev->config_size - config.offset" subtraction results in a very high u32 value. The vhost_vdpa_config_validate() function has a similar issue, but there the "size" is long type so the subtraction works on 64bit system and this change only affects 32bit systems. Fixes: c8a6153b6c59 ("vduse: Introduce VDUSE - vDPA Device in Userspace") Fixes: 4c8cf31885f6 ("vhost: introduce vDPA-based backend") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> --- v2: the first version had a reversed if statement v3: fix vhost_vdpa_config_validate() as pointed out by Yongji Xie. drivers/vdpa/vdpa_user/vduse_dev.c | 3 ++- drivers/vhost/vdpa.c | 2 +- 2 files changed, 3 insertions(+), 2 deletions(-)