From 55c537734f476d04c18f67083642b96bbead6219 Mon Sep 17 00:00:00 2001
From: Phil Sutter <psutter@redhat.com>
Date: Mon, 27 Jan 2020 16:11:41 +0100
Subject: [PATCH] netlink: Avoid potential NULL-pointer deref in
netlink_gen_payload_stmt()
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1793030
Upstream Status: nftables commit c9ddf0bff363f
commit c9ddf0bff363fc9101b563b592db600bdf4d65c5
Author: Phil Sutter <phil@nwl.cc>
Date: Mon Jan 20 16:32:40 2020 +0100
netlink: Avoid potential NULL-pointer deref in netlink_gen_payload_stmt()
With payload_needs_l4csum_update_pseudohdr() unconditionally
dereferencing passed 'desc' parameter and a previous check for it to be
non-NULL, make sure to call the function only if input is sane.
Fixes: 68de70f2b3fc6 ("netlink_linearize: fix IPv6 layer 4 checksum mangling")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
src/netlink_linearize.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c
index 498326d..cb1b7fe 100644
--- a/src/netlink_linearize.c
+++ b/src/netlink_linearize.c
@@ -941,7 +941,7 @@ static void netlink_gen_payload_stmt(struct netlink_linearize_ctx *ctx,
nftnl_expr_set_u32(nle, NFTNL_EXPR_PAYLOAD_CSUM_OFFSET,
csum_off / BITS_PER_BYTE);
}
- if (expr->payload.base == PROTO_BASE_NETWORK_HDR &&
+ if (expr->payload.base == PROTO_BASE_NETWORK_HDR && desc &&
payload_needs_l4csum_update_pseudohdr(expr, desc))
nftnl_expr_set_u32(nle, NFTNL_EXPR_PAYLOAD_FLAGS,
NFT_PAYLOAD_L4CSUM_PSEUDOHDR);
--
2.31.1