Re: [PATCH 1/2 v2 net-next] thunderbolt: Fix a couple right shifting to zero bugs

[David Miller]

From: Dan Carpenter 
Date: Tue, 17 Oct 2017 15:32:17 +0300

> 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 

Applied.

[PATCH 1/2 v2 net-next] thunderbolt: Fix a couple right shifting to zero bugs

[Dan Carpenter]

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 
---
v2: I accidentally sent this through the wrong list, so I'm resending to
netdev.  Also Mika asked me to split it up because the Fixes tags
are different for these patches.

diff --git a/drivers/thunderbolt/xdomain.c b/drivers/thunderbolt/xdomain.c
index 138027537d29..ff8d91189e99 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);