NVMe: Don't allow unsupported flags

The command flags can change the meaning of other fields in the command
that the driver is not prepared to handle. Specifically, the user could
passthrough an SGL flag, causing the controller to misinterpret the PRP
list the driver created, potentially corrupting memory or data.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Jon Derrick <jonathan.derrick@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 7fd5a7ac8375e3b0ecef8413b28a1a5e5fb579e5..ba15015141285d169761f68cef5f1d370bc04b5a 100644 (file)
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -374,6 +374,8 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
 
        if (copy_from_user(&io, uio, sizeof(io)))
                return -EFAULT;
+       if (io.flags)
+               return -EINVAL;
 
        switch (io.opcode) {
        case nvme_cmd_write:
@@ -425,6 +427,8 @@ static int nvme_user_cmd(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
                return -EACCES;
        if (copy_from_user(&cmd, ucmd, sizeof(cmd)))
                return -EFAULT;
+       if (cmd.flags)
+               return -EINVAL;
 
        memset(&c, 0, sizeof(c));
        c.common.opcode = cmd.opcode;