[PATCH v3 1/2] io_uring: refactor io_uring_allowed()

Hamza Mahfooz
2025-01-27T15:59:34Z

Have io_uring_allowed() return an error code directly instead of
true/false. This is needed for follow-up work to guard io_uring_setup()
with LSM.

Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Hamza Mahfooz <hamzamahfooz@linux.microsoft.com>
---
io_uring/io_uring.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 7bfbc7c22367..c2d8bd4c2cfc 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -3789,29 +3789,36 @@ static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
return io_uring_create(entries, &p, params);
}

-static inline bool io_uring_allowed(void)
+static inline int io_uring_allowed(void)
{
int disabled = READ_ONCE(sysctl_io_uring_disabled);
kgid_t io_uring_group;

if (disabled == 2)
- return false;
+ return -EPERM;

if (disabled == 0 || capable(CAP_SYS_ADMIN))
- return true;
+ goto allowed_lsm;

io_uring_group = make_kgid(&init_user_ns, sysctl_io_uring_group);
if (!gid_valid(io_uring_group))
- return false;
+ return -EPERM;
+
+ if (!in_group_p(io_uring_group))
+ return -EPERM;

- return in_group_p(io_uring_group);
+allowed_lsm:
+ return 0;
}

SYSCALL_DEFINE2(io_uring_setup, u32, entries,
struct io_uring_params __user *, params)
{
- if (!io_uring_allowed())
- return -EPERM;
+ int ret;
+
+ ret = io_uring_allowed();
+ if (ret)
+ return ret;

return io_uring_setup(entries, params);
}
--
2.47.1