[PATCH] thunderbolt: Fix some right shifting to zero bugs

From: Dan Carpenter
Date: Fri Oct 13 2017 - 07:30:50 EST


The problematic code looks like this:

res_seq = res_hdr->xd_hdr.length_sn & TB_XDOMAIN_SN_MASK;
res_seq >>= TB_XDOMAIN_SN_SHIFT;

TB_XDOMAIN_SN_SHIFT is 27, and right shifting a u8 27 bits is always
going to result in zero. The fix is to declare these variables as u32.

Fixes: d1ff70241a27 ("thunderbolt: Add support for XDomain discovery protocol")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

diff --git a/drivers/thunderbolt/xdomain.c b/drivers/thunderbolt/xdomain.c
index f2d06f6f7be9..c6ca170e1f4f 100644
--- a/drivers/thunderbolt/xdomain.c
+++ b/drivers/thunderbolt/xdomain.c
@@ -56,7 +56,7 @@ static bool tb_xdomain_match(const struct tb_cfg_request *req,
case TB_CFG_PKG_XDOMAIN_RESP: {
const struct tb_xdp_header *res_hdr = pkg->buffer;
const struct tb_xdp_header *req_hdr = req->request;
- u8 req_seq, res_seq;
+ u32 req_seq, res_seq;

if (pkg->frame.size < req->response_size / 4)
return false;
@@ -476,7 +476,7 @@ static void tb_xdp_handle_request(struct work_struct *work)
struct tb_ctl *ctl = tb->ctl;
const uuid_t *uuid;
int ret = 0;
- u8 sequence;
+ u32 sequence;
u64 route;

route = ((u64)xhdr->route_hi << 32 | xhdr->route_lo) & ~BIT_ULL(63);
diff --git a/drivers/net/thunderbolt.c b/drivers/net/thunderbolt.c
index 1a7bc0bf4598..435854688a7a 100644
--- a/drivers/net/thunderbolt.c
+++ b/drivers/net/thunderbolt.c
@@ -394,7 +394,7 @@ static int tbnet_handle_packet(const void *buf, size_t size, void *data)
struct tbnet *net = data;
u32 command_id;
int ret = 0;
- u8 sequence;
+ u32 sequence;
u64 route;

/* Make sure the packet is for us */