From: Pavel Begunkov <[email protected]>
To: Jens Axboe <[email protected]>,
[email protected], [email protected]
Subject: [PATCH 4/4] io_uring: don't read user-shared sqe flags twice
Date: Wed, 8 Apr 2020 08:58:46 +0300 [thread overview]
Message-ID: <d4f7cf7ff796e3cfdd54db36153dac29ea9f3a56.1586325467.git.asml.silence@gmail.com> (raw)
In-Reply-To: <[email protected]>
Don't re-read userspace-shared sqe->flags, it can be exploited.
sqe->flags are copied into req->flags in io_submit_sqe(), check them
instead.
Signed-off-by: Pavel Begunkov <[email protected]>
---
fs/io_uring.c | 20 ++++++++------------
1 file changed, 8 insertions(+), 12 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 072e002f1184..f8173a77434c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2930,7 +2930,7 @@ static int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
if (sqe->ioprio || sqe->buf_index)
return -EINVAL;
- if (sqe->flags & IOSQE_FIXED_FILE)
+ if (req->flags & REQ_F_FIXED_FILE)
return -EBADF;
if (req->flags & REQ_F_NEED_CLEANUP)
return 0;
@@ -2961,7 +2961,7 @@ static int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
if (sqe->ioprio || sqe->buf_index)
return -EINVAL;
- if (sqe->flags & IOSQE_FIXED_FILE)
+ if (req->flags & REQ_F_FIXED_FILE)
return -EBADF;
if (req->flags & REQ_F_NEED_CLEANUP)
return 0;
@@ -3315,7 +3315,7 @@ static int io_statx_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
if (sqe->ioprio || sqe->buf_index)
return -EINVAL;
- if (sqe->flags & IOSQE_FIXED_FILE)
+ if (req->flags & REQ_F_FIXED_FILE)
return -EBADF;
if (req->flags & REQ_F_NEED_CLEANUP)
return 0;
@@ -3392,7 +3392,7 @@ static int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
if (sqe->ioprio || sqe->off || sqe->addr || sqe->len ||
sqe->rw_flags || sqe->buf_index)
return -EINVAL;
- if (sqe->flags & IOSQE_FIXED_FILE)
+ if (req->flags & REQ_F_FIXED_FILE)
return -EBADF;
req->close.fd = READ_ONCE(sqe->fd);
@@ -5363,15 +5363,10 @@ static int io_file_get(struct io_submit_state *state, struct io_kiocb *req,
}
static int io_req_set_file(struct io_submit_state *state, struct io_kiocb *req,
- const struct io_uring_sqe *sqe)
+ int fd, unsigned int flags)
{
- unsigned flags;
- int fd;
bool fixed;
- flags = READ_ONCE(sqe->flags);
- fd = READ_ONCE(sqe->fd);
-
if (!io_req_needs_file(req, fd))
return 0;
@@ -5613,7 +5608,7 @@ static bool io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
{
struct io_ring_ctx *ctx = req->ctx;
unsigned int sqe_flags;
- int ret, id;
+ int ret, id, fd;
sqe_flags = READ_ONCE(sqe->flags);
@@ -5644,7 +5639,8 @@ static bool io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
IOSQE_ASYNC | IOSQE_FIXED_FILE |
IOSQE_BUFFER_SELECT);
- ret = io_req_set_file(state, req, sqe);
+ fd = READ_ONCE(sqe->fd);
+ ret = io_req_set_file(state, req, fd, sqe_flags);
if (unlikely(ret)) {
err_req:
io_cqring_add_event(req, ret);
--
2.24.0
next prev parent reply other threads:[~2020-04-08 6:00 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-08 5:58 [PATCH 0/4] clean early submission path Pavel Begunkov
2020-04-08 5:58 ` [PATCH 1/4] io_uring: simplify io_get_sqring Pavel Begunkov
2020-04-08 5:58 ` [PATCH 2/4] io_uring: alloc req only after getting sqe Pavel Begunkov
2020-04-08 5:58 ` [PATCH 3/4] io_uring: remove req init from io_get_req() Pavel Begunkov
2020-04-08 5:58 ` Pavel Begunkov [this message]
2020-04-08 15:27 ` [PATCH 0/4] clean early submission path Jens Axboe
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