From 55c537734f476d04c18f67083642b96bbead6219 Mon Sep 17 00:00:00 2001 From: Phil Sutter 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 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 Acked-by: Pablo Neira Ayuso --- 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); -- 1.8.3.1