[4.19,139/267] media: cec: silence shift wrapping warning in __cec_s_log_addrs()

Message ID 20200619141655.496890579@linuxfoundation.org
State New
Headers show
Series
  • Untitled series #28331
Related show

Commit Message

Greg Kroah-Hartman June 19, 2020, 2:32 p.m.
From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit 3b5af3171e2d5a73ae6f04965ed653d039904eb6 ]

The log_addrs->log_addr_type[i] value is a u8 which is controlled by
the user and comes from the ioctl.  If it's over 31 then that results in
undefined behavior (shift wrapping) and that leads to a Smatch static
checker warning.  We already cap the value later so we can silence the
warning just by re-ordering the existing checks.

I think the UBSan checker will also catch this bug at runtime and
generate a warning.  But otherwise the bug is harmless.

Fixes: 9881fe0ca187 ("[media] cec: add HDMI CEC framework (adapter)")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/media/cec/cec-adap.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Patch

diff --git a/drivers/media/cec/cec-adap.c b/drivers/media/cec/cec-adap.c
index ba7e976bf6dc..60b20ae02b05 100644
--- a/drivers/media/cec/cec-adap.c
+++ b/drivers/media/cec/cec-adap.c
@@ -1668,6 +1668,10 @@  int __cec_s_log_addrs(struct cec_adapter *adap,
 		unsigned j;
 
 		log_addrs->log_addr[i] = CEC_LOG_ADDR_INVALID;
+		if (log_addrs->log_addr_type[i] > CEC_LOG_ADDR_TYPE_UNREGISTERED) {
+			dprintk(1, "unknown logical address type\n");
+			return -EINVAL;
+		}
 		if (type_mask & (1 << log_addrs->log_addr_type[i])) {
 			dprintk(1, "duplicate logical address type\n");
 			return -EINVAL;
@@ -1688,10 +1692,6 @@  int __cec_s_log_addrs(struct cec_adapter *adap,
 			dprintk(1, "invalid primary device type\n");
 			return -EINVAL;
 		}
-		if (log_addrs->log_addr_type[i] > CEC_LOG_ADDR_TYPE_UNREGISTERED) {
-			dprintk(1, "unknown logical address type\n");
-			return -EINVAL;
-		}
 		for (j = 0; j < feature_sz; j++) {
 			if ((features[j] & 0x80) == 0) {
 				if (op_is_dev_features)