[RFC 2/2] nvme: Use CAP_FIRMWARE_UPGRADE to check user commands

From: Mario Limonciello
Date: Thu Feb 18 2021 - 13:58:56 EST


Software that is running with CAP_FIRMWARE_UPGRADE needs a limited
set of opcode access:
* Identify the disk
* Download firmware to the disk
* Commit the firmwware to the disk

Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxxx>
---
drivers/nvme/host/core.c | 28 ++++++++++++++++++++++++----
1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index f13eb4ded95f..80be3d6b7437 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1593,13 +1593,23 @@ static int nvme_user_cmd(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
u64 result;
int status;

- if (!capable(CAP_SYS_ADMIN))
- return -EACCES;
if (copy_from_user(&cmd, ucmd, sizeof(cmd)))
return -EFAULT;
if (cmd.flags)
return -EINVAL;

+ switch (cmd.opcode) {
+ case nvme_admin_identify:
+ case nvme_admin_activate_fw:
+ case nvme_admin_download_fw:
+ if (!firmware_upgrade_capable())
+ return -EACCES;
+ break;
+ default:
+ if (!capable(CAP_SYS_ADMIN))
+ return -EACCES;
+ }
+
memset(&c, 0, sizeof(c));
c.common.opcode = cmd.opcode;
c.common.flags = cmd.flags;
@@ -1637,13 +1647,23 @@ static int nvme_user_cmd64(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
unsigned timeout = 0;
int status;

- if (!capable(CAP_SYS_ADMIN))
- return -EACCES;
if (copy_from_user(&cmd, ucmd, sizeof(cmd)))
return -EFAULT;
if (cmd.flags)
return -EINVAL;

+ switch (cmd.opcode) {
+ case nvme_admin_identify:
+ case nvme_admin_activate_fw:
+ case nvme_admin_download_fw:
+ if (!firmware_upgrade_capable())
+ return -EACCES;
+ break;
+ default:
+ if (!capable(CAP_SYS_ADMIN))
+ return -EACCES;
+ }
+
memset(&c, 0, sizeof(c));
c.common.opcode = cmd.opcode;
c.common.flags = cmd.flags;
--
2.25.1