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authorPavel Begunkov <asml.silence@gmail.com>2024-07-18 20:00:53 +0100
committerJens Axboe <axboe@kernel.dk>2024-07-20 11:04:57 -0600
commitbcc87d978b834c298bbdd9c52454c5d0a946e97e (patch)
tree5856e3d2a6a03b6a89d8828ee4fc3dab8fa7b4f1 /io_uring
parent24dce1c538a7ceac43f2f97aae8dfd4bb93ea9b9 (diff)
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>
Diffstat (limited to 'io_uring')
-rw-r--r--io_uring/kbuf.c4
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;