Merge tag 'nvme-6.2-2022-12-29' of git://git.infradead.org/nvme into block-6.2block-6.2-2022-12-29

Pull NVMe fixes from Christoph:

"nvme fixes for Linux 6.2

 - fix various problems in handling the Command Supported and Effects log
   (Christoph Hellwig)
 - don't allow unprivileged passthrough of commands that don't transfer
   data but modify logical block content (Christoph Hellwig)
 - add a features and quirks policy document (Christoph Hellwig)
 - fix some really nasty code that was correct but made smatch complain
   (Sagi Grimberg)"

* tag 'nvme-6.2-2022-12-29' of git://git.infradead.org/nvme:
  nvme-auth: fix smatch warning complaints
  nvme: consult the CSE log page for unprivileged passthrough
  nvme: also return I/O command effects from nvme_command_effects
  nvmet: don't defer passthrough commands with trivial effects to the workqueue
  nvmet: set the LBCC bit for commands that modify data
  nvmet: use NVME_CMD_EFFECTS_CSUPP instead of open coding it
  nvme: fix the NVME_CMD_EFFECTS_CSE_MASK definition
  docs, nvme: add a feature and quirk policy document

1 files changed, 24 insertions, 4 deletions

diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
index 9ddda571f046..a8639919237e 100644
--- a/drivers/nvme/host/ioctl.c
+++ b/drivers/nvme/host/ioctl.c
@@ -11,6 +11,8 @@
 static bool nvme_cmd_allowed(struct nvme_ns *ns, struct nvme_command *c,
 		fmode_t mode)
 {
+	u32 effects;
+
 	if (capable(CAP_SYS_ADMIN))
 		return true;
 
@@ -43,11 +45,29 @@ static bool nvme_cmd_allowed(struct nvme_ns *ns, struct nvme_command *c,
 	}
 
 	/*
-	 * Only allow I/O commands that transfer data to the controller if the
-	 * special file is open for writing, but always allow I/O commands that
-	 * transfer data from the controller.
+	 * Check if the controller provides a Commands Supported and Effects log
+	 * and marks this command as supported.  If not reject unprivileged
+	 * passthrough.
+	 */
+	effects = nvme_command_effects(ns->ctrl, ns, c->common.opcode);
+	if (!(effects & NVME_CMD_EFFECTS_CSUPP))
+		return false;
+
+	/*
+	 * Don't allow passthrough for command that have intrusive (or unknown)
+	 * effects.
+	 */
+	if (effects & ~(NVME_CMD_EFFECTS_CSUPP | NVME_CMD_EFFECTS_LBCC |
+			NVME_CMD_EFFECTS_UUID_SEL |
+			NVME_CMD_EFFECTS_SCOPE_MASK))
+		return false;
+
+	/*
+	 * Only allow I/O commands that transfer data to the controller or that
+	 * change the logical block contents if the file descriptor is open for
+	 * writing.
 	 */
-	if (nvme_is_write(c))
+	if (nvme_is_write(c) || (effects & NVME_CMD_EFFECTS_LBCC))
 		return mode & FMODE_WRITE;
 	return true;
 }