diff options
| author | Jens Axboe <axboe@kernel.dk> | 2023-10-18 08:09:27 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2023-10-18 09:22:14 -0600 |
| commit | 8b51a3956d44ea6ade962874ade14de9a7d16556 (patch) | |
| tree | 68d32782914d90a89fe10ff3170b709350bd4db0 /io_uring | |
| parent | 0f8baa3c9802fbfe313c901e1598397b61b91ada (diff) | |
| download | linux-8b51a3956d44ea6ade962874ade14de9a7d16556.tar.gz | |
io_uring: fix crash with IORING_SETUP_NO_MMAP and invalid SQ ring address
If we specify a valid CQ ring address but an invalid SQ ring address,
we'll correctly spot this and free the allocated pages and clear them
to NULL. However, we don't clear the ring page count, and hence will
attempt to free the pages again. We've already cleared the address of
the page array when freeing them, but we don't check for that. This
causes the following crash:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
Oops [#1]
Modules linked in:
CPU: 0 PID: 20 Comm: kworker/u2:1 Not tainted 6.6.0-rc5-dirty #56
Hardware name: ucbbar,riscvemu-bare (DT)
Workqueue: events_unbound io_ring_exit_work
epc : io_pages_free+0x2a/0x58
ra : io_rings_free+0x3a/0x50
epc : ffffffff808811a2 ra : ffffffff80881406 sp : ffff8f80000c3cd0
status: 0000000200000121 badaddr: 0000000000000000 cause: 000000000000000d
[<ffffffff808811a2>] io_pages_free+0x2a/0x58
[<ffffffff80881406>] io_rings_free+0x3a/0x50
[<ffffffff80882176>] io_ring_exit_work+0x37e/0x424
[<ffffffff80027234>] process_one_work+0x10c/0x1f4
[<ffffffff8002756e>] worker_thread+0x252/0x31c
[<ffffffff8002f5e4>] kthread+0xc4/0xe0
[<ffffffff8000332a>] ret_from_fork+0xa/0x1c
Check for a NULL array in io_pages_free(), but also clear the page counts
when we free them to be on the safer side.
Reported-by: rtm@csail.mit.edu
Fixes: 03d89a2de25b ("io_uring: support for user allocated memory for rings/sqes")
Cc: stable@vger.kernel.org
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/io_uring.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index d839a80a6751c1..8d1bc6cdfe712e 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -2674,7 +2674,11 @@ static void io_pages_free(struct page ***pages, int npages) if (!pages) return; + page_array = *pages; + if (!page_array) + return; + for (i = 0; i < npages; i++) unpin_user_page(page_array[i]); kvfree(page_array); @@ -2758,7 +2762,9 @@ static void io_rings_free(struct io_ring_ctx *ctx) ctx->sq_sqes = NULL; } else { io_pages_free(&ctx->ring_pages, ctx->n_ring_pages); + ctx->n_ring_pages = 0; io_pages_free(&ctx->sqe_pages, ctx->n_sqe_pages); + ctx->n_sqe_pages = 0; } } |