Commit 1d2ac7b6 authored Oct 13, 2021 by Bodo Stroesser Committed by Martin K. Petersen Oct 18, 2021

scsi: target: tcmu: Allocate zeroed pages for data area

Tcmu populates the data area (used for communication with userspace) with
pages that are allocated by calling alloc_page(GFP_NOIO). Therefore
previous content of the allocated pages is exposed to user space. Avoid
this by adding __GFP_ZERO flag.

Zeroing the pages does (nearly) not affect tcmu throughput, because
allocated pages are re-used for the data transfers of later SCSI cmds.

Link: https://lore.kernel.org/r/20211013171606.25197-1-bostroesser@gmail.com

Signed-off-by: Bodo Stroesser <bostroesser@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

parent d1e51ea6

drivers/target/target_core_user.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -523,8 +523,8 @@ static inline int tcmu_get_empty_block(struct tcmu_dev *udev,
		rcu_read_unlock();

		for (i = cnt; i < page_cnt; i++) {
		/* try to get new page from the mm */
		page = alloc_page(GFP_NOIO);
		/* try to get new zeroed page from the mm */
		page = alloc_page(GFP_NOIO \| __GFP_ZERO);
		if (!page)
		break;