Dan Carpenter
2021-Dec-07 11:48 UTC
[PATCH v3] vduse: vduse: check that offsets are within bounds
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 at 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(-)
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
Jason Wang
2021-Dec-08 03:43 UTC
[PATCH v3] vduse: vduse: check that offsets are within bounds
On Tue, Dec 7, 2021 at 7:49 PM Dan Carpenter <dan.carpenter at 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 at 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 >