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authorPavel Begunkov <asml.silence@gmail.com>2022-06-09 08:34:35 +0100
committerPavel Begunkov <asml.silence@gmail.com>2022-06-13 09:53:41 +0100
commit05b538c1765f8d14a71ccf5f85258dcbeaf189f7 (patch)
treeb9ea721f301a58633b99cef2fd5da753e89729c1 /fs
parentd11d31fc5d8a96f707facee0babdcffaafa38de2 (diff)
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io_uring: fix not locked access to fixed buf table
We can look inside the fixed buffer table only while holding ->uring_lock, however in some cases we don't do the right async prep for IORING_OP_{WRITE,READ}_FIXED ending up with NULL req->imu forcing making an io-wq worker to try to resolve the fixed buffer without proper locking. Move req->imu setup into early req init paths, i.e. io_prep_rw(), which is called unconditionally for rw requests and under uring_lock. Fixes: 634d00df5e1cf ("io_uring: add full-fledged dynamic buffers support") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/io_uring.c34
1 files changed, 17 insertions, 17 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index be05f375a776..fd8a1ffe6a1a 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3636,6 +3636,20 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
int ret;
kiocb->ki_pos = READ_ONCE(sqe->off);
+ /* used for fixed read/write too - just read unconditionally */
+ req->buf_index = READ_ONCE(sqe->buf_index);
+
+ if (req->opcode == IORING_OP_READ_FIXED ||
+ req->opcode == IORING_OP_WRITE_FIXED) {
+ struct io_ring_ctx *ctx = req->ctx;
+ u16 index;
+
+ if (unlikely(req->buf_index >= ctx->nr_user_bufs))
+ return -EFAULT;
+ index = array_index_nospec(req->buf_index, ctx->nr_user_bufs);
+ req->imu = ctx->user_bufs[index];
+ io_req_set_rsrc_node(req, ctx, 0);
+ }
ioprio = READ_ONCE(sqe->ioprio);
if (ioprio) {
@@ -3648,12 +3662,9 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
kiocb->ki_ioprio = get_current_ioprio();
}
- req->imu = NULL;
req->rw.addr = READ_ONCE(sqe->addr);
req->rw.len = READ_ONCE(sqe->len);
req->rw.flags = READ_ONCE(sqe->rw_flags);
- /* used for fixed read/write too - just read unconditionally */
- req->buf_index = READ_ONCE(sqe->buf_index);
return 0;
}
@@ -3785,20 +3796,9 @@ static int __io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter
static int io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter,
unsigned int issue_flags)
{
- struct io_mapped_ubuf *imu = req->imu;
- u16 index, buf_index = req->buf_index;
-
- if (likely(!imu)) {
- struct io_ring_ctx *ctx = req->ctx;
-
- if (unlikely(buf_index >= ctx->nr_user_bufs))
- return -EFAULT;
- io_req_set_rsrc_node(req, ctx, issue_flags);
- index = array_index_nospec(buf_index, ctx->nr_user_bufs);
- imu = READ_ONCE(ctx->user_bufs[index]);
- req->imu = imu;
- }
- return __io_import_fixed(req, rw, iter, imu);
+ if (WARN_ON_ONCE(!req->imu))
+ return -EFAULT;
+ return __io_import_fixed(req, rw, iter, req->imu);
}
static int io_buffer_add_list(struct io_ring_ctx *ctx,