Merge branch 'master' into for-linus

1 files changed, 16 insertions, 0 deletions

diff --git a/net/wireless/wext-core.c b/net/wireless/wext-core.c
index 0ef17bc..8f5116f 100644
--- a/net/wireless/wext-core.c
+++ b/net/wireless/wext-core.c
@@ -782,6 +782,22 @@ static int ioctl_standard_iw_point(struct iw_point *iwp, unsigned int cmd,
 		}
 	}
 
+	if (IW_IS_GET(cmd) && !(descr->flags & IW_DESCR_FLAG_NOMAX)) {
+		/*
+		 * If this is a GET, but not NOMAX, it means that the extra
+		 * data is not bounded by userspace, but by max_tokens. Thus
+		 * set the length to max_tokens. This matches the extra data
+		 * allocation.
+		 * The driver should fill it with the number of tokens it
+		 * provided, and it may check iwp->length rather than having
+		 * knowledge of max_tokens. If the driver doesn't change the
+		 * iwp->length, this ioctl just copies back max_token tokens
+		 * filled with zeroes. Hopefully the driver isn't claiming
+		 * them to be valid data.
+		 */
+		iwp->length = descr->max_tokens;
+	}
+
 	err = handler(dev, info, (union iwreq_data *) iwp, extra);
 
 	iwp->length += essid_compat;