[PATCH 5.4 189/240] ata: libata-core: fix NULL pointer deref in ata_host_alloc_pinfo()

Greg Kroah-Hartman
2022-06-20T14:10:32Z

From: Sergey Shtylyov <s.shtylyov@omp.ru>

[ Upstream commit bf476fe22aa1851bab4728e0c49025a6a0bea307 ]

In an unlikely (and probably wrong?) case that the 'ppi' parameter of
ata_host_alloc_pinfo() points to an array starting with a NULL pointer,
there's going to be a kernel oops as the 'pi' local variable won't get
reassigned from the initial value of NULL. Initialize 'pi' instead to
'&ata_dummy_port_info' to fix the possible kernel oops for good...

Found by Linux Verification Center (linuxtesting.org) with the SVACE static
analysis tool.

Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/ata/libata-core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index af8a1bac9345..fc37e075f3e1 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -6235,7 +6235,7 @@ struct ata_host *ata_host_alloc_pinfo(struct device *dev,
const struct ata_port_info * const * ppi,
int n_ports)
{
- const struct ata_port_info *pi;
+ const struct ata_port_info *pi = &ata_dummy_port_info;
struct ata_host *host;
int i, j;

@@ -6243,7 +6243,7 @@ struct ata_host *ata_host_alloc_pinfo(struct device *dev,
if (!host)
return NULL;

- for (i = 0, j = 0, pi = NULL; i < host->n_ports; i++) {
+ for (i = 0, j = 0; i < host->n_ports; i++) {
struct ata_port *ap = host->ports[i];

if (ppi[j])
--
2.35.1