From c6d3d9cbd659de8f2176b4e4721149c88ac096d4 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@gmail.com>
Date: Tue, 31 Aug 2021 14:13:10 +0100
Subject: [PATCH] io_uring: fix queueing half-created requests
Git-commit: c6d3d9cbd659de8f2176b4e4721149c88ac096d4
Patch-mainline: v5.15-rc1
References: bsc#1205205
[ 27.259845] general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] SMP KASAN PTI
[ 27.261043] KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
[ 27.263730] RIP: 0010:sock_from_file+0x20/0x90
[ 27.272444] Call Trace:
[ 27.272736] io_sendmsg+0x98/0x600
[ 27.279216] io_issue_sqe+0x498/0x68d0
[ 27.281142] __io_queue_sqe+0xab/0xb50
[ 27.285830] io_req_task_submit+0xbf/0x1b0
[ 27.286306] tctx_task_work+0x178/0xad0
[ 27.288211] task_work_run+0xe2/0x190
[ 27.288571] exit_to_user_mode_prepare+0x1a1/0x1b0
[ 27.289041] syscall_exit_to_user_mode+0x19/0x50
[ 27.289521] do_syscall_64+0x48/0x90
[ 27.289871] entry_SYSCALL_64_after_hwframe+0x44/0xae
io_req_complete_failed() -> io_req_complete_post() ->
io_req_task_queue() still would try to enqueue hard linked request,
which can be half prepared (e.g. failed init), so we can't allow
that to happen.
Fixes: a8295b982c46d ("io_uring: fix failed linkchain code logic")
Reported-by: syzbot+f9704d1878e290eddf73@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/70b513848c1000f88bd75965504649c6bb1415c0.1630415423.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
---
fs/io_uring.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 364e77d5fe6c..78f3d3ac2280 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1823,6 +1823,17 @@ static void io_req_complete_failed(struct io_kiocb *req, long res)
io_req_complete_post(req, res, 0);
}
+static void io_req_complete_fail_submit(struct io_kiocb *req)
+{
+ /*
+ * We don't submit, fail them all, for that replace hardlinks with
+ * normal links. Extra REQ_F_LINK is tolerated.
+ */
+ req->flags &= ~REQ_F_HARDLINK;
+ req->flags |= REQ_F_LINK;
+ io_req_complete_failed(req, req->result);
+}
+
/*
* Don't initialise the fields below on every allocation, but do that in
* advance and keep them valid across allocations.
@@ -6723,7 +6734,7 @@ static inline void io_queue_sqe(struct io_kiocb *req)
if (likely(!(req->flags & (REQ_F_FORCE_ASYNC | REQ_F_FAIL)))) {
__io_queue_sqe(req);
} else if (req->flags & REQ_F_FAIL) {
- io_req_complete_failed(req, req->result);
+ io_req_complete_fail_submit(req);
} else {
int ret = io_req_prep_async(req);
--
2.35.3