[34-longterm 123/260] drivers/net/cxgb3/cxgb3_main.c: prevent reading uninitialized stack memory

[Paul Gortmaker]

From: Dan Rosenberg <drosenberg@xxxxxxxxxxxxx>

commit 49c37c0334a9b85d30ab3d6b5d1acb05ef2ef6de upstream.

Fixed formatting (tabs and line breaks).

The CHELSIO_GET_QSET_NUM device ioctl allows unprivileged users to read
4 bytes of uninitialized stack memory, because the "addr" member of the
ch_reg struct declared on the stack in cxgb_extension_ioctl() is not
altered or zeroed before being copied back to the user.  This patch
takes care of it.

Signed-off-by: Dan Rosenberg <dan.j.rosenberg@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
 drivers/net/cxgb3/cxgb3_main.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/net/cxgb3/cxgb3_main.c b/drivers/net/cxgb3/cxgb3_main.c
index e3f1b85..3e0f19f 100644
--- a/drivers/net/cxgb3/cxgb3_main.c
+++ b/drivers/net/cxgb3/cxgb3_main.c
@@ -2296,6 +2296,8 @@ static int cxgb_extension_ioctl(struct net_device *dev, void __user *useraddr)
 	case CHELSIO_GET_QSET_NUM:{
 		struct ch_reg edata;
 
+		memset(&edata, 0, sizeof(struct ch_reg));
+
 		edata.cmd = CHELSIO_GET_QSET_NUM;
 		edata.val = pi->nqsets;
 		if (copy_to_user(useraddr, &edata, sizeof(edata)))
-- 
1.7.3.3

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