From: Govindarajulu Varadarajan <govind.varadar@gmail.com>
To: io-uring@vger.kernel.org, axboe@kernel.dk
Cc: ming.lei@redhat.com, kbusch@kernel.org, hch@lst.de,
sagi@grimberg.me, miklos@szeredi.hu,
Govindarajulu Varadarajan <govind.varadar@gmail.com>
Subject: [PATCH 1/2] io_uring: Add size check for sqe->cmd
Date: Thu, 29 Jan 2026 12:13:46 -0800 [thread overview]
Message-ID: <20260129201347.411015-2-govind.varadar@gmail.com> (raw)
In-Reply-To: <20260129201347.411015-1-govind.varadar@gmail.com>
For SQE128, sqe->cmd provides 80 bytes for uring_cmd. Add macro to
check if size of user struct does not exceed 80 bytes at compile time.
User doesn't have to track this manually during development.
Replace io_uring_sqe_cmd() with IO_URING_SQE_CMD() which checks struct
size for 16 bytes cmd.
Signed-off-by: Govindarajulu Varadarajan <govind.varadar@gmail.com>
---
drivers/block/ublk_drv.c | 14 ++++++++------
drivers/nvme/host/ioctl.c | 2 +-
fs/fuse/dev_uring.c | 6 ++++--
include/linux/io_uring/cmd.h | 15 +++++++++++----
4 files changed, 24 insertions(+), 13 deletions(-)
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 4265b7610c95..7c8a23709efa 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -3155,7 +3155,7 @@ static int ublk_ch_uring_cmd_local(struct io_uring_cmd *cmd,
unsigned int issue_flags)
{
/* May point to userspace-mapped memory */
- const struct ublksrv_io_cmd *ub_src = io_uring_sqe_cmd(cmd->sqe);
+ const struct ublksrv_io_cmd *ub_src = IO_URING_SQE_CMD(cmd->sqe, struct ublksrv_io_cmd);
u16 buf_idx = UBLK_INVALID_BUF_IDX;
struct ublk_device *ub = cmd->file->private_data;
struct ublk_queue *ubq;
@@ -3735,7 +3735,7 @@ static int ublk_validate_batch_fetch_cmd(struct ublk_batch_io_data *data)
static int ublk_handle_non_batch_cmd(struct io_uring_cmd *cmd,
unsigned int issue_flags)
{
- const struct ublksrv_io_cmd *ub_cmd = io_uring_sqe_cmd(cmd->sqe);
+ const struct ublksrv_io_cmd *ub_cmd = IO_URING_SQE_CMD(cmd->sqe, struct ublksrv_io_cmd);
struct ublk_device *ub = cmd->file->private_data;
unsigned tag = READ_ONCE(ub_cmd->tag);
unsigned q_id = READ_ONCE(ub_cmd->q_id);
@@ -3764,7 +3764,7 @@ static int ublk_handle_non_batch_cmd(struct io_uring_cmd *cmd,
static int ublk_ch_batch_io_uring_cmd(struct io_uring_cmd *cmd,
unsigned int issue_flags)
{
- const struct ublk_batch_io *uc = io_uring_sqe_cmd(cmd->sqe);
+ const struct ublk_batch_io *uc = IO_URING_SQE_CMD(cmd->sqe, struct ublk_batch_io);
struct ublk_device *ub = cmd->file->private_data;
struct ublk_batch_io_data data = {
.ub = ub,
@@ -4653,7 +4653,8 @@ static int ublk_ctrl_del_dev(struct ublk_device **p_ub, bool wait)
static inline void ublk_ctrl_cmd_dump(struct io_uring_cmd *cmd)
{
- const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
+ const struct ublksrv_ctrl_cmd *header = IO_URING_SQE128_CMD(cmd->sqe,
+ struct ublksrv_ctrl_cmd);
pr_devel("%s: cmd_op %x, dev id %d qid %d data %llx buf %llx len %u\n",
__func__, cmd->cmd_op, header->dev_id, header->queue_id,
@@ -5061,7 +5062,7 @@ static int ublk_char_dev_permission(struct ublk_device *ub,
static int ublk_ctrl_uring_cmd_permission(struct ublk_device *ub,
struct io_uring_cmd *cmd)
{
- struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)io_uring_sqe_cmd(cmd->sqe);
+ struct ublksrv_ctrl_cmd *header = IO_URING_SQE128_CMD(cmd->sqe, struct ublksrv_ctrl_cmd);
bool unprivileged = ub->dev_info.flags & UBLK_F_UNPRIVILEGED_DEV;
void __user *argp = (void __user *)(unsigned long)header->addr;
char *dev_path = NULL;
@@ -5152,7 +5153,8 @@ static bool ublk_ctrl_uring_cmd_may_sleep(u32 cmd_op)
static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd,
unsigned int issue_flags)
{
- const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
+ const struct ublksrv_ctrl_cmd *header = IO_URING_SQE128_CMD(cmd->sqe,
+ struct ublksrv_ctrl_cmd);
struct ublk_device *ub = NULL;
u32 cmd_op = cmd->cmd_op;
int ret = -EINVAL;
diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
index fb62633ccbb0..90c49bb727ad 100644
--- a/drivers/nvme/host/ioctl.c
+++ b/drivers/nvme/host/ioctl.c
@@ -447,7 +447,7 @@ static int nvme_uring_cmd_io(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
struct io_uring_cmd *ioucmd, unsigned int issue_flags, bool vec)
{
struct nvme_uring_cmd_pdu *pdu = nvme_uring_cmd_pdu(ioucmd);
- const struct nvme_uring_cmd *cmd = io_uring_sqe_cmd(ioucmd->sqe);
+ const struct nvme_uring_cmd *cmd = IO_URING_SQE128_CMD(ioucmd->sqe, struct nvme_uring_cmd);
struct request_queue *q = ns ? ns->queue : ctrl->admin_q;
struct nvme_uring_data d;
struct nvme_command c;
diff --git a/fs/fuse/dev_uring.c b/fs/fuse/dev_uring.c
index 5ceb217ced1b..7dddba72f406 100644
--- a/fs/fuse/dev_uring.c
+++ b/fs/fuse/dev_uring.c
@@ -879,7 +879,8 @@ static int fuse_ring_ent_set_commit(struct fuse_ring_ent *ent)
static int fuse_uring_commit_fetch(struct io_uring_cmd *cmd, int issue_flags,
struct fuse_conn *fc)
{
- const struct fuse_uring_cmd_req *cmd_req = io_uring_sqe_cmd(cmd->sqe);
+ const struct fuse_uring_cmd_req *cmd_req = IO_URING_SQE128_CMD(cmd->sqe,
+ struct fuse_uring_cmd_req);
struct fuse_ring_ent *ent;
int err;
struct fuse_ring *ring = fc->ring;
@@ -1083,7 +1084,8 @@ fuse_uring_create_ring_ent(struct io_uring_cmd *cmd,
static int fuse_uring_register(struct io_uring_cmd *cmd,
unsigned int issue_flags, struct fuse_conn *fc)
{
- const struct fuse_uring_cmd_req *cmd_req = io_uring_sqe_cmd(cmd->sqe);
+ const struct fuse_uring_cmd_req *cmd_req = IO_URING_SQE128_CMD(cmd->sqe,
+ struct fuse_uring_cmd_req);
struct fuse_ring *ring = smp_load_acquire(&fc->ring);
struct fuse_ring_queue *queue;
struct fuse_ring_ent *ent;
diff --git a/include/linux/io_uring/cmd.h b/include/linux/io_uring/cmd.h
index 375fd048c4cb..e8fd93e90cde 100644
--- a/include/linux/io_uring/cmd.h
+++ b/include/linux/io_uring/cmd.h
@@ -20,10 +20,17 @@ struct io_uring_cmd {
u8 unused[8];
};
-static inline const void *io_uring_sqe_cmd(const struct io_uring_sqe *sqe)
-{
- return sqe->cmd;
-}
+#define IO_URING_SQE128_CMD(sqe, type) ({ \
+ BUILD_BUG_ON(sizeof(type) > ((2 * sizeof(struct io_uring_sqe)) - \
+ offsetof(struct io_uring_sqe, cmd))); \
+ (type *)(sqe)->cmd; \
+})
+
+#define IO_URING_SQE_CMD(sqe, type) ({ \
+ BUILD_BUG_ON(sizeof(type) > ((sizeof(struct io_uring_sqe)) - \
+ offsetof(struct io_uring_sqe, cmd))); \
+ (type *)(sqe)->cmd; \
+})
static inline void io_uring_cmd_private_sz_check(size_t cmd_sz)
{
--
2.52.0
next prev parent reply other threads:[~2026-01-29 20:14 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-29 20:13 [PATCH 0/2] io_uring: Add macro to validate SQE cmd size Govindarajulu Varadarajan
2026-01-29 20:13 ` Govindarajulu Varadarajan [this message]
2026-01-29 20:19 ` [PATCH 1/2] io_uring: Add size check for sqe->cmd Jens Axboe
2026-01-29 20:48 ` Caleb Sander Mateos
2026-01-30 5:11 ` Christoph Hellwig
2026-01-29 20:13 ` [PATCH 2/2] block/ublk_drv: Validate SQE128 flag before accessing the cmd Govindarajulu Varadarajan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260129201347.411015-2-govind.varadar@gmail.com \
--to=govind.varadar@gmail.com \
--cc=axboe@kernel.dk \
--cc=hch@lst.de \
--cc=io-uring@vger.kernel.org \
--cc=kbusch@kernel.org \
--cc=miklos@szeredi.hu \
--cc=ming.lei@redhat.com \
--cc=sagi@grimberg.me \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox