[PATCH 4.19 046/243] virtchnl: Fix off by one error

Greg Kroah-Hartman
2019-12-11T15:17:41Z

From: Alice Michael <alice.michael@intel.com>

[ Upstream commit 843faff87af261bf55eda719a06087af0486a168 ]

When calculating the valid length for a VIRTCHNL_OP_ENABLE_CHANNELS
message, we accidentally allowed messages with one extra
virtchnl_channel_info structure on the end. This happened due
to an off by one error, because we forgot that valid_len already
accounted for one virtchnl_channel_info structure, so we need to
subtract one from the num_tc value.

Signed-off-by: Alice Michael <alice.michael@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/linux/avf/virtchnl.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/avf/virtchnl.h b/include/linux/avf/virtchnl.h
index 212b3822d1804..92d179fb6d59e 100644
--- a/include/linux/avf/virtchnl.h
+++ b/include/linux/avf/virtchnl.h
@@ -798,8 +798,8 @@ virtchnl_vc_validate_vf_msg(struct virtchnl_version_info *ver, u32 v_opcode,
if (msglen >= valid_len) {
struct virtchnl_tc_info *vti =
(struct virtchnl_tc_info *)msg;
- valid_len += vti->num_tc *
- sizeof(struct virtchnl_channel_info);
+ valid_len += (vti->num_tc - 1) *
+ sizeof(struct virtchnl_channel_info);
if (vti->num_tc == 0)
err_msg_format = true;
}
--
2.20.1