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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Yafang Shao <laoar.shao@gmail.com>,
        David Ahern <dsahern@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Johannes Berg <johannes@sipsolutions.net>,
        Shailabh Nagar <nagar@watson.ibm.com>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH 4.19 37/54] tools/accounting/getdelays.c: fix netlink attribute length
Date:   Sat, 11 Apr 2020 14:09:19 +0200
Message-Id: <20200411115512.207596545@linuxfoundation.org>
In-Reply-To: <20200411115508.284500414@linuxfoundation.org>
References: <20200411115508.284500414@linuxfoundation.org>
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From: David Ahern <dsahern@kernel.org>

commit 4054ab64e29bb05b3dfe758fff3c38a74ba753bb upstream.

A recent change to the netlink code: 6e237d099fac ("netlink: Relax attr
validation for fixed length types") logs a warning when programs send
messages with invalid attributes (e.g., wrong length for a u32).  Yafang
reported this error message for tools/accounting/getdelays.c.

send_cmd() is wrongly adding 1 to the attribute length.  As noted in
include/uapi/linux/netlink.h nla_len should be NLA_HDRLEN + payload
length, so drop the +1.

Fixes: 9e06d3f9f6b1 ("per task delay accounting taskstats interface: documentation fix")
Reported-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Yafang Shao <laoar.shao@gmail.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200327173111.63922-1-dsahern@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 tools/accounting/getdelays.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/tools/accounting/getdelays.c
+++ b/tools/accounting/getdelays.c
@@ -136,7 +136,7 @@ static int send_cmd(int sd, __u16 nlmsg_
 	msg.g.version = 0x1;
 	na = (struct nlattr *) GENLMSG_DATA(&msg);
 	na->nla_type = nla_type;
-	na->nla_len = nla_len + 1 + NLA_HDRLEN;
+	na->nla_len = nla_len + NLA_HDRLEN;
 	memcpy(NLA_DATA(na), nla_data, nla_len);
 	msg.n.nlmsg_len += NLMSG_ALIGN(na->nla_len);