Commit 2a584012 authored by Luis Chamberlain's avatar Luis Chamberlain Committed by Paul Moore
Browse files

lsm,io_uring: add LSM hooks for the new uring_cmd file op 

io-uring cmd support was added through ee692a21 ("fs,io_uring:
add infrastructure for uring-cmd"), this extended the struct
file_operations to allow a new command which each subsystem can use
to enable command passthrough. Add an LSM specific for the command
passthrough which enables LSMs to inspect the command details.

This was discussed long ago without no clear pointer for something
conclusive, so this enables LSMs to at least reject this new file
operation.

[0] https://lkml.kernel.org/r/8adf55db-7bab-f59d-d612-ed906b948d19@schaufler-ca.com



Cc: stable@vger.kernel.org
Fixes: ee692a21 ("fs,io_uring: add infrastructure for uring-cmd")
Signed-off-by: default avatarLuis Chamberlain <mcgrof@kernel.org>
Acked-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarPaul Moore <paul@paul-moore.com>
parent 568035b0

include/linux/lsm_hook_defs.h

+1 −0
Original line number Diff line number Diff line
@@ -407,4 +407,5 @@ LSM_HOOK(int, 0, perf_event_write, struct perf_event *event) 
#ifdef CONFIG_IO_URING

LSM_HOOK(int, 0, uring_override_creds, const struct cred *new)

LSM_HOOK(int, 0, uring_sqpoll, void)

LSM_HOOK(int, 0, uring_cmd, struct io_uring_cmd *ioucmd)

#endif /* CONFIG_IO_URING */

include/linux/lsm_hooks.h

+3 −0
Original line number Diff line number Diff line
@@ -1582,6 +1582,9 @@ 
 *      Check whether the current task is allowed to spawn a io_uring polling

 *      thread (IORING_SETUP_SQPOLL).

 *

 * @uring_cmd:

 *      Check whether the file_operations uring_cmd is allowed to run.

 *

 */

union security_list_options {

	#define LSM_HOOK(RET, DEFAULT, NAME, ...) RET (*NAME)(__VA_ARGS__);

include/linux/security.h

+5 −0
Original line number Diff line number Diff line
@@ -2060,6 +2060,7 @@ static inline int security_perf_event_write(struct perf_event *event) 
#ifdef CONFIG_SECURITY

extern int security_uring_override_creds(const struct cred *new);

extern int security_uring_sqpoll(void);

extern int security_uring_cmd(struct io_uring_cmd *ioucmd);

#else

static inline int security_uring_override_creds(const struct cred *new)

{
@@ -2069,6 +2070,10 @@ static inline int security_uring_sqpoll(void) 
{

	return 0;

}

static inline int security_uring_cmd(struct io_uring_cmd *ioucmd)

{

	return 0;

}

#endif /* CONFIG_SECURITY */

#endif /* CONFIG_IO_URING */

io_uring/uring_cmd.c

+5 −0
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 
#include <linux/errno.h>

#include <linux/file.h>

#include <linux/io_uring.h>

#include <linux/security.h>



#include <uapi/linux/io_uring.h>
@@ -88,6 +89,10 @@ int io_uring_cmd(struct io_kiocb *req, unsigned int issue_flags) 
	if (!req->file->f_op->uring_cmd)

		return -EOPNOTSUPP;



	ret = security_uring_cmd(ioucmd);

	if (ret)

		return ret;



	if (ctx->flags & IORING_SETUP_SQE128)

		issue_flags |= IO_URING_F_SQE128;

	if (ctx->flags & IORING_SETUP_CQE32)

security/security.c

+4 −0
Original line number Diff line number Diff line
@@ -2660,4 +2660,8 @@ int security_uring_sqpoll(void) 
{

	return call_int_hook(uring_sqpoll, 0);

}

int security_uring_cmd(struct io_uring_cmd *ioucmd)

{

	return call_int_hook(uring_cmd, 0, ioucmd);

}

#endif /* CONFIG_IO_URING */