[PATCH] staging: gasket: Check the return value of gasket_get_bar_index()

Oscar Carter
2020-05-01T15:51:57Z

Check the return value of gasket_get_bar_index function as it can return
a negative one (-EINVAL). If this happens, a negative index is used in
the "gasket_dev->bar_data" array.

Addresses-Coverity-ID: 1438542 ("Negative array index read")
Fixes: 9a69f5087ccc2 ("drivers/staging: Gasket driver framework + Apex driver")
Signed-off-by: Oscar Carter <oscar.carter@gmx.com>
---
drivers/staging/gasket/gasket_core.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/staging/gasket/gasket_core.c b/drivers/staging/gasket/gasket_core.c
index 8e0575fcb4c8..67325fbaf760 100644
--- a/drivers/staging/gasket/gasket_core.c
+++ b/drivers/staging/gasket/gasket_core.c
@@ -925,6 +925,10 @@ do_map_region(const struct gasket_dev *gasket_dev, struct vm_area_struct *vma,
gasket_get_bar_index(gasket_dev,
(vma->vm_pgoff << PAGE_SHIFT) +
driver_desc->legacy_mmap_address_offset);
+
+ if (bar_index < 0)
+ return DO_MAP_REGION_INVALID;
+
phys_base = gasket_dev->bar_data[bar_index].phys_base + phys_offset;
while (mapped_bytes < map_length) {
/*
--
2.20.1