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| author | Pavel Begunkov <asml.silence@gmail.com> | 2024-12-26 17:49:23 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2024-12-26 18:02:40 +0100 |
| commit | e33ac68e5e21ec1292490dfe061e75c0dbdd3bd4 (patch) | |
| tree | f5d69c0145c61a1f80ed794b26e69f251772fa83 /io_uring | |
| parent | io_uring: check if iowq is killed before queuing (diff) | |
| download | linux-e33ac68e5e21ec1292490dfe061e75c0dbdd3bd4.tar.xz linux-e33ac68e5e21ec1292490dfe061e75c0dbdd3bd4.zip | |
io_uring/sqpoll: fix sqpoll error handling races
BUG: KASAN: slab-use-after-free in __lock_acquire+0x370b/0x4a10 kernel/locking/lockdep.c:5089
Call Trace:
<TASK>
...
_raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162
class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:551 [inline]
try_to_wake_up+0xb5/0x23c0 kernel/sched/core.c:4205
io_sq_thread_park+0xac/0xe0 io_uring/sqpoll.c:55
io_sq_thread_finish+0x6b/0x310 io_uring/sqpoll.c:96
io_sq_offload_create+0x162/0x11d0 io_uring/sqpoll.c:497
io_uring_create io_uring/io_uring.c:3724 [inline]
io_uring_setup+0x1728/0x3230 io_uring/io_uring.c:3806
...
Kun Hu reports that the SQPOLL creating error path has UAF, which
happens if io_uring_alloc_task_context() fails and then io_sq_thread()
manages to run and complete before the rest of error handling code,
which means io_sq_thread_finish() is looking at already killed task.
Note that this is mostly theoretical, requiring fault injection on
the allocation side to trigger in practice.
Cc: stable@vger.kernel.org
Reported-by: Kun Hu <huk23@m.fudan.edu.cn>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0f2f1aa5729332612bd01fe0f2f385fd1f06ce7c.1735231717.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/sqpoll.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/io_uring/sqpoll.c b/io_uring/sqpoll.c index 6df5e649c413..9e5bd79fd2b5 100644 --- a/io_uring/sqpoll.c +++ b/io_uring/sqpoll.c @@ -405,6 +405,7 @@ void io_sqpoll_wait_sq(struct io_ring_ctx *ctx) __cold int io_sq_offload_create(struct io_ring_ctx *ctx, struct io_uring_params *p) { + struct task_struct *task_to_put = NULL; int ret; /* Retain compatibility with failing for an invalid attach attempt */ @@ -480,6 +481,7 @@ __cold int io_sq_offload_create(struct io_ring_ctx *ctx, } sqd->thread = tsk; + task_to_put = get_task_struct(tsk); ret = io_uring_alloc_task_context(tsk, ctx); wake_up_new_task(tsk); if (ret) @@ -490,11 +492,15 @@ __cold int io_sq_offload_create(struct io_ring_ctx *ctx, goto err; } + if (task_to_put) + put_task_struct(task_to_put); return 0; err_sqpoll: complete(&ctx->sq_data->exited); err: io_sq_thread_finish(ctx); + if (task_to_put) + put_task_struct(task_to_put); return ret; } |