diff options
| author | Jens Axboe <axboe@kernel.dk> | 2020-02-22 23:22:19 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-02-23 19:46:13 -0700 |
| commit | 193155c8c9429f57400daf1f2ef0075016767112 (patch) | |
| tree | 27dfc2f52a5a871c07f7c221e308dbe040f2a13e | |
| parent | f8788d86ab28f61f7b46eb6be375f8a726783636 (diff) | |
io_uring: handle multiple personalities in link chains
If we have a chain of requests and they don't all use the same
credentials, then the head of the chain will be issued with the
credentails of the tail of the chain.
Ensure __io_queue_sqe() overrides the credentials, if they are different.
Once we do that, we can clean up the creds handling as well, by only
having io_submit_sqe() do the lookup of a personality. It doesn't need
to assign it, since __io_queue_sqe() now always does the right thing.
Fixes: 75c6a03904e0 ("io_uring: support using a registered personality for commands")
Reported-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | fs/io_uring.c | 25 |
1 files changed, 15 insertions, 10 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index de650df9ac53..7d0be264527d 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -4705,11 +4705,21 @@ static void __io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_kiocb *linked_timeout; struct io_kiocb *nxt = NULL; + const struct cred *old_creds = NULL; int ret; again: linked_timeout = io_prep_linked_timeout(req); + if (req->work.creds && req->work.creds != current_cred()) { + if (old_creds) + revert_creds(old_creds); + if (old_creds == req->work.creds) + old_creds = NULL; /* restored original creds */ + else + old_creds = override_creds(req->work.creds); + } + ret = io_issue_sqe(req, sqe, &nxt, true); /* @@ -4759,6 +4769,8 @@ done_req: goto punt; goto again; } + if (old_creds) + revert_creds(old_creds); } static void io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe) @@ -4803,7 +4815,6 @@ static inline void io_queue_link_head(struct io_kiocb *req) static bool io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe, struct io_submit_state *state, struct io_kiocb **link) { - const struct cred *old_creds = NULL; struct io_ring_ctx *ctx = req->ctx; unsigned int sqe_flags; int ret, id; @@ -4818,14 +4829,12 @@ static bool io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe, id = READ_ONCE(sqe->personality); if (id) { - const struct cred *personality_creds; - - personality_creds = idr_find(&ctx->personality_idr, id); - if (unlikely(!personality_creds)) { + req->work.creds = idr_find(&ctx->personality_idr, id); + if (unlikely(!req->work.creds)) { ret = -EINVAL; goto err_req; } - old_creds = override_creds(personality_creds); + get_cred(req->work.creds); } /* same numerical values with corresponding REQ_F_*, safe to copy */ @@ -4837,8 +4846,6 @@ static bool io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe, err_req: io_cqring_add_event(req, ret); io_double_put_req(req); - if (old_creds) - revert_creds(old_creds); return false; } @@ -4899,8 +4906,6 @@ err_req: } } - if (old_creds) - revert_creds(old_creds); return true; } |