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 if
out of bounds then the "dev->config_size - config.offset" subtraction
results in a very high u32 value. The out of bounds offset can result
in memory corruption.
Fixes: c8a6153b6c59 ("vduse: Introduce VDUSE - vDPA Device in Userspace")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
v2: fix reversed if statement
v3: fix vhost_vdpa_config_validate() as pointed out by Yongji Xie.
v4: split the vhost_vdpa_config_validate() change into a separate path
drivers/vdpa/vdpa_user/vduse_dev.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
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;
--
2.20.1
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