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 v2] io_uring: Add size check for sqe->cmd
Date: Thu, 29 Jan 2026 15:54:34 -0800 [thread overview]
Message-ID: <20260129235434.418973-1-govind.varadar@gmail.com> (raw)
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() inline func with macro and add
io_uring_sqe128_cmd() which checks struct
size for 16 bytes cmd and 80 bytes cmd respectively.
Signed-off-by: Govindarajulu Varadarajan <govind.varadar@gmail.com>
---
v2:
- Replace all caps macro with lower case definition.
- Add const qualifier to return type.
- Rebase on top of series "[PATCH 0/4] ublk: fix struct
ublksrv_ctrl_cmd accesses"
BRANCH: for-7.0/block
Depends-on series: "[PATCH 0/4] ublk: fix struct ublksrv_ctrl_cmd
accesses"
Needs "[PATCH 2/4] ublk: don't write to struct ublksrv_ctrl_cmd" to
avoid merge conflict.
---
drivers/block/ublk_drv.c | 14 +++++++++-----
drivers/nvme/host/ioctl.c | 3 ++-
fs/fuse/dev_uring.c | 6 ++++--
include/linux/io_uring/cmd.h | 15 +++++++++++----
4 files changed, 26 insertions(+), 12 deletions(-)
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 0e25a59849ae..3f9d6dc3afef 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -3244,7 +3244,8 @@ 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;
@@ -3824,7 +3825,8 @@ 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);
@@ -3853,7 +3855,7 @@ 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,
@@ -5106,7 +5108,8 @@ 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, u64 *addr, u16 *len)
{
- 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);
bool unprivileged = ub->dev_info.flags & UBLK_F_UNPRIVILEGED_DEV;
void __user *argp = (void __user *)*addr;
char *dev_path = NULL;
@@ -5199,7 +5202,8 @@ 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..8844bbd39515 100644
--- a/drivers/nvme/host/ioctl.c
+++ b/drivers/nvme/host/ioctl.c
@@ -447,7 +447,8 @@ 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..60f2058feb74 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..7245b975c55d 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))); \
+ (const 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))); \
+ (const type *)(sqe)->cmd; \
+})
static inline void io_uring_cmd_private_sz_check(size_t cmd_sz)
{
--
2.52.0
next reply other threads:[~2026-01-29 23:54 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-29 23:54 Govindarajulu Varadarajan [this message]
2026-01-30 1:27 ` [PATCH v2] io_uring: Add size check for sqe->cmd Caleb Sander Mateos
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=20260129235434.418973-1-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