6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Caleb Sander Mateos [ Upstream commit 3831568792af75b6523fa93bb91560e29189cf55 ] 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 Signed-off-by: Sasha Levin --- 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 bd0b2046981e4..7fd286d8aadb2 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -915,7 +915,10 @@ static int ublk_map_io(const struct ublk_queue *ubq, const struct request *req, struct iov_iter iter; const int dir = ITER_DEST; - import_ubuf(dir, u64_to_user_ptr(io->addr), rq_bytes, &iter); + if (import_ubuf(dir, u64_to_user_ptr(io->addr), rq_bytes, + &iter) < 0) + return 0; + return ublk_copy_user_pages(req, 0, &iter, dir); } return rq_bytes; @@ -936,7 +939,10 @@ static int ublk_unmap_io(const struct ublk_queue *ubq, WARN_ON_ONCE(io->res > rq_bytes); - import_ubuf(dir, u64_to_user_ptr(io->addr), io->res, &iter); + if (import_ubuf(dir, u64_to_user_ptr(io->addr), io->res, + &iter) < 0) + return 0; + return ublk_copy_user_pages(req, 0, &iter, dir); } return rq_bytes; -- 2.53.0