6.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jens Axboe axboe@kernel.dk
[ Upstream commit e0ee967630c8ee67bb47a5b38d235cd5a8789c48 ]
Harden the buffer peeking a bit, by adding a sanity check for it having a valid size. Outside of that, arg->max_len is a size_t, though it's only ever set to a 32-bit value (as it's governed by MAX_RW_COUNT). Bump our needed check to a size_t so we know it fits. Finally, cap the calculated needed iov value to the PEEK_MAX_IMPORT, which is the maximum number of segments that should be peeked.
Fixes: 35c8711c8fc4 ("io_uring/kbuf: add helpers for getting/peeking multiple buffers") Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- io_uring/kbuf.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c index c95dc1736dd93..1af2bd56af44a 100644 --- a/io_uring/kbuf.c +++ b/io_uring/kbuf.c @@ -218,10 +218,13 @@ static int io_ring_buffers_peek(struct io_kiocb *req, struct buf_sel_arg *arg,
buf = io_ring_head_to_buf(br, head, bl->mask); if (arg->max_len) { - int needed; + u32 len = READ_ONCE(buf->len); + size_t needed;
- needed = (arg->max_len + buf->len - 1) / buf->len; - needed = min(needed, PEEK_MAX_IMPORT); + if (unlikely(!len)) + return -ENOBUFS; + needed = (arg->max_len + len - 1) / len; + needed = min_not_zero(needed, (size_t) PEEK_MAX_IMPORT); if (nr_avail > needed) nr_avail = needed; }