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| author | Pavel Begunkov <asml.silence@gmail.com> | 2024-07-18 20:00:53 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2024-07-20 11:04:57 -0600 |
| commit | bcc87d978b834c298bbdd9c52454c5d0a946e97e (patch) | |
| tree | 5856e3d2a6a03b6a89d8828ee4fc3dab8fa7b4f1 | |
| parent | 24dce1c538a7ceac43f2f97aae8dfd4bb93ea9b9 (diff) | |
| download | lwn-bcc87d978b834c298bbdd9c52454c5d0a946e97e.tar.gz lwn-bcc87d978b834c298bbdd9c52454c5d0a946e97e.zip | |
io_uring: fix error pbuf checking
Syz reports a problem, which boils down to NULL vs IS_ERR inconsistent
error handling in io_alloc_pbuf_ring().
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
RIP: 0010:__io_remove_buffers+0xac/0x700 io_uring/kbuf.c:341
Call Trace:
<TASK>
io_put_bl io_uring/kbuf.c:378 [inline]
io_destroy_buffers+0x14e/0x490 io_uring/kbuf.c:392
io_ring_ctx_free+0xa00/0x1070 io_uring/io_uring.c:2613
io_ring_exit_work+0x80f/0x8a0 io_uring/io_uring.c:2844
process_one_work kernel/workqueue.c:3231 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
worker_thread+0x86d/0xd40 kernel/workqueue.c:3390
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
Cc: stable@vger.kernel.org
Reported-by: syzbot+2074b1a3d447915c6f1c@syzkaller.appspotmail.com
Fixes: 87585b05757dc ("io_uring/kbuf: use vm_insert_pages() for mmap'ed pbuf ring")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/c5f9df20560bd9830401e8e48abc029e7cfd9f5e.1721329239.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | io_uring/kbuf.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c index d2945c9c812b..c95dc1736dd9 100644 --- a/io_uring/kbuf.c +++ b/io_uring/kbuf.c @@ -657,8 +657,10 @@ static int io_alloc_pbuf_ring(struct io_ring_ctx *ctx, ring_size = reg->ring_entries * sizeof(struct io_uring_buf_ring); bl->buf_ring = io_pages_map(&bl->buf_pages, &bl->buf_nr_pages, ring_size); - if (!bl->buf_ring) + if (IS_ERR(bl->buf_ring)) { + bl->buf_ring = NULL; return -ENOMEM; + } bl->is_buf_ring = 1; bl->is_mmap = 1; |