nvme: identify-namespace without CAP_SYS_ADMIN

Allow all identify-namespace variants (CNS 00h, 05h and 08h) without
requiring CAP_SYS_ADMIN. The information (retrieved using id-ns) is
needed to form IO commands for passthrough interface.

Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
index 1d68f161064ae188e830985a8c9b14b91e7c57af..9550a69029b3688a29d373e6628d3c661f280621 100644 (file)
--- a/drivers/nvme/host/ioctl.c
+++ b/drivers/nvme/host/ioctl.c
@@ -22,9 +22,23 @@ static bool nvme_cmd_allowed(struct nvme_ns *ns, struct nvme_command *c,
            c->common.opcode == nvme_fabrics_command)
                return false;
 
-       /* do not allow unprivileged admin commands */
-       if (!ns)
+       /*
+        * Do not allow unprivileged passthrough of admin commands except
+        * for a subset of identify commands that contain information required
+        * to form proper I/O commands in userspace and do not expose any
+        * potentially sensitive information.
+        */
+       if (!ns) {
+               if (c->common.opcode == nvme_admin_identify) {
+                       switch (c->identify.cns) {
+                       case NVME_ID_CNS_NS:
+                       case NVME_ID_CNS_CS_NS:
+                       case NVME_ID_CNS_NS_CS_INDEP:
+                               return true;
+                       }
+               }
                return false;
+       }
 
        /*
         * Only allow I/O commands that transfer data to the controller if the