[PATCH 4.4 035/112] VMCI: check return value of get_user_pages_fast() for errors

Greg Kroah-Hartman
2020-10-27T13:58:08Z

From: Alex Dewar <alex.dewar90@gmail.com>

[ Upstream commit 90ca6333fd65f318c47bff425e1ea36c0a5539f6 ]

In a couple of places in qp_host_get_user_memory(),
get_user_pages_fast() is called without properly checking for errors. If
e.g. -EFAULT is returned, this negative value will then be passed on to
qp_release_pages(), which expects a u64 as input.

Fix this by only calling qp_release_pages() when we have a positive
number returned.

Fixes: 06164d2b72aa ("VMCI: queue pairs implementation.")
Signed-off-by: Alex Dewar <alex.dewar90@gmail.com>
Link: https://lore.kernel.org/r/20200825164522.412392-1-alex.dewar90@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/misc/vmw_vmci/vmci_queue_pair.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/misc/vmw_vmci/vmci_queue_pair.c b/drivers/misc/vmw_vmci/vmci_queue_pair.c
index 3877f534fd3f4..e57340e980c4b 100644
--- a/drivers/misc/vmw_vmci/vmci_queue_pair.c
+++ b/drivers/misc/vmw_vmci/vmci_queue_pair.c
@@ -758,8 +758,9 @@ static int qp_host_get_user_memory(u64 produce_uva,
if (retval < (int)produce_q->kernel_if->num_pages) {
pr_debug("get_user_pages_fast(produce) failed (retval=%d)",
retval);
- qp_release_pages(produce_q->kernel_if->u.h.header_page,
- retval, false);
+ if (retval > 0)
+ qp_release_pages(produce_q->kernel_if->u.h.header_page,
+ retval, false);
err = VMCI_ERROR_NO_MEM;
goto out;
}
@@ -770,8 +771,9 @@ static int qp_host_get_user_memory(u64 produce_uva,
if (retval < (int)consume_q->kernel_if->num_pages) {
pr_debug("get_user_pages_fast(consume) failed (retval=%d)",
retval);
- qp_release_pages(consume_q->kernel_if->u.h.header_page,
- retval, false);
+ if (retval > 0)
+ qp_release_pages(consume_q->kernel_if->u.h.header_page,
+ retval, false);
qp_release_pages(produce_q->kernel_if->u.h.header_page,
produce_q->kernel_if->num_pages, false);
err = VMCI_ERROR_NO_MEM;
--
2.25.1