From 3831568792af75b6523fa93bb91560e29189cf55 Mon Sep 17 00:00:00 2001 From: Caleb Sander Mateos Date: Wed, 29 Jul 2026 11:10:39 -0600 Subject: [PATCH] ublk: check import_ubuf() return value import_ubuf() can fail if the address range (provided by the userspace ublk server) is outside the allowed user address space. Return that 0 bytes were copied if import_ubuf() fails rather than passing an uninitialized struct iov_iter to ublk_copy_user_pages(). Fixes: 981f95a571e3 ("ublk: cleanup ublk_copy_user_pages") Reported-by: Ming Lei Signed-off-by: Caleb Sander Mateos Link: https://patch.msgid.link/20260729171041.45061-2-csander@purestorage.com Signed-off-by: Jens Axboe --- drivers/block/ublk_drv.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index 4ca6ec738c93..098e046505ad 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -1475,7 +1475,10 @@ static unsigned int ublk_map_io(const struct ublk_queue *ubq, struct iov_iter iter; const int dir = ITER_DEST; - import_ubuf(dir, u64_to_user_ptr(io->buf.addr), rq_bytes, &iter); + if (import_ubuf(dir, u64_to_user_ptr(io->buf.addr), rq_bytes, + &iter) < 0) + return 0; + return ublk_copy_user_pages(req, 0, &iter, dir); } return rq_bytes; @@ -1496,7 +1499,10 @@ static unsigned int ublk_unmap_io(bool need_map, WARN_ON_ONCE(io->res > rq_bytes); - import_ubuf(dir, u64_to_user_ptr(io->buf.addr), io->res, &iter); + if (import_ubuf(dir, u64_to_user_ptr(io->buf.addr), io->res, + &iter) < 0) + return 0; + return ublk_copy_user_pages(req, 0, &iter, dir); } return rq_bytes;