[PATCH v2 2/4] nvme: reject invalid pr_read_keys() num_keys values

Stefan Hajnoczi
2025-11-27T15:54:39Z

The pr_read_keys() interface has a u32 num_keys parameter. The NVMe
Reservation Report command has a u32 maximum length. Reject num_keys
values that are too large to fit.

This will become important when pr_read_keys() is exposed to untrusted
userspace via an <linux/pr.h> ioctl.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
drivers/nvme/host/pr.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/nvme/host/pr.c b/drivers/nvme/host/pr.c
index ca6a74607b139..156a2ae1fac2e 100644
--- a/drivers/nvme/host/pr.c
+++ b/drivers/nvme/host/pr.c
@@ -233,6 +233,10 @@ static int nvme_pr_read_keys(struct block_device *bdev,
int ret, i;
bool eds;

+ /* Check that keys fit into u32 rse_len */
+ if (num_keys > (U32_MAX - sizeof(*rse)) / sizeof(rse->regctl_eds[0]))
+ return -EINVAL;
+
/*
* Assume we are using 128-bit host IDs and allocate a buffer large
* enough to get enough keys to fill the return keys buffer.
--
2.52.0