diff options
| author | Thadeu Lima de Souza Cascardo | 2021-05-05 09:47:06 -0300 |
|---|---|---|
| committer | Jens Axboe | 2021-05-05 15:17:35 -0600 |
| commit | d1f82808877bb10d3deee7cf3374a4eb3fb582db (patch) | |
| tree | 7fd2853c3824a097c0c67b3f28255b3467d5741a | |
| parent | bb6659cc0ad3c2afc3801b708b19c4c67e55ddf2 (diff) | |
io_uring: truncate lengths larger than MAX_RW_COUNT on provide buffers
Read and write operations are capped to MAX_RW_COUNT. Some read ops rely on
that limit, and that is not guaranteed by the IORING_OP_PROVIDE_BUFFERS.
Truncate those lengths when doing io_add_buffers, so buffer addresses still
use the uncapped length.
Also, take the chance and change struct io_buffer len member to __u32, so
it matches struct io_provide_buffer len member.
This fixes CVE-2021-3491, also reported as ZDI-CAN-13546.
Fixes: ddf0322db79c ("io_uring: add IORING_OP_PROVIDE_BUFFERS")
Reported-by: Billy Jheng Bing-Jhong (@st424204)
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | fs/io_uring.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index 7a2e83bc005d..f46acbbeed57 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -251,7 +251,7 @@ struct io_rsrc_data { struct io_buffer { struct list_head list; __u64 addr; - __s32 len; + __u32 len; __u16 bid; }; @@ -3986,7 +3986,7 @@ static int io_add_buffers(struct io_provide_buf *pbuf, struct io_buffer **head) break; buf->addr = addr; - buf->len = pbuf->len; + buf->len = min_t(__u32, pbuf->len, MAX_RW_COUNT); buf->bid = bid; addr += pbuf->len; bid++; |