From 6854ec003b42cf02d4b40c0942d49ede9f6d94c0 Mon Sep 17 00:00:00 2001
From: Phil Sutter <psutter@redhat.com>
Date: Wed, 19 Feb 2020 12:00:31 +0100
Subject: [PATCH] src: Fix for reading garbage in nftnl_chain getters

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1758673
Upstream Status: libnftnl commit 629ee38dca486

commit 629ee38dca48651bc8c0eedf2f3a0066a6c0aa5b
Author: Phil Sutter <phil@nwl.cc>
Date:   Fri Feb 14 18:20:29 2020 +0100

    src: Fix for reading garbage in nftnl_chain getters

    In {s,u}{32,64} type getters nftnl_assert() is called to make sure
    returned data length matches expectations. Therefore all attributes must
    set data_len, which NFTNL_CHAIN_DEVICES didn't.

    While being at it, do the same change for NFTNL_FLOWTABLE_DEVICES as
    well to make code a bit more consistent although the problem was fixed
    for flowtables with commit f8eed54150fd4 ("flowtable: Fix for reading
    garbage") already (but in the other direction).

    Fixes: e3ac19b5ec162 ("chain: multi-device support")
    Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 src/chain.c     | 1 +
 src/flowtable.c | 1 +
 2 files changed, 2 insertions(+)

diff --git a/src/chain.c b/src/chain.c
index b9a16fc..6e90763 100644
--- a/src/chain.c
+++ b/src/chain.c
@@ -365,6 +365,7 @@ const void *nftnl_chain_get_data(const struct nftnl_chain *c, uint16_t attr,
 		*data_len = strlen(c->dev) + 1;
 		return c->dev;
 	case NFTNL_CHAIN_DEVICES:
+		*data_len = 0;
 		return &c->dev_array[0];
 	}
 	return NULL;
diff --git a/src/flowtable.c b/src/flowtable.c
index 9ba3b6d..bf3e443 100644
--- a/src/flowtable.c
+++ b/src/flowtable.c
@@ -231,6 +231,7 @@ const void *nftnl_flowtable_get_data(const struct nftnl_flowtable *c,
 		*data_len = sizeof(int32_t);
 		return &c->family;
 	case NFTNL_FLOWTABLE_DEVICES:
+		*data_len = 0;
 		return &c->dev_array[0];
 	case NFTNL_FLOWTABLE_SIZE:
 		*data_len = sizeof(int32_t);
-- 
1.8.3.1