From 72859f25cb799ba4ac0b532c59bd01be70950f00 Mon Sep 17 00:00:00 2001
From: Phil Sutter <psutter@redhat.com>
Date: Fri, 15 Mar 2019 17:51:28 +0100
Subject: [PATCH] libiptc: Avoid side-effect in memset() calls

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1525980
Upstream Status: iptables commit e6f986762667e

commit e6f986762667ee2b2d61e7978d460f28916158a3
Author: Phil Sutter <phil@nwl.cc>
Date:   Mon Sep 10 23:35:14 2018 +0200

    libiptc: Avoid side-effect in memset() calls

    These calls to memset() are passed a length argument which exceeds
    t->target.u.user.name's length by one byte and hence overwrite
    t->target.u.user.revision as well (relying upon no padding to happen
    between both).

    Avoid this obscure behaviour by passing the correct field size and
    explicitly overwriting 'revision' field.

    Signed-off-by: Phil Sutter <phil@nwl.cc>
    Signed-off-by: Florian Westphal <fw@strlen.de>

Signed-off-by: Phil Sutter <psutter@redhat.com>
---
 libiptc/libiptc.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libiptc/libiptc.c b/libiptc/libiptc.c
index d2427c16a5254..4c0fbd5d7e68c 100644
--- a/libiptc/libiptc.c
+++ b/libiptc/libiptc.c
@@ -1115,8 +1115,9 @@ static inline int iptcc_compile_rule (struct xtc_handle *h, STRUCT_REPLACE *repl
 		STRUCT_STANDARD_TARGET *t;
 		t = (STRUCT_STANDARD_TARGET *)GET_TARGET(r->entry);
 		/* memset for memcmp convenience on delete/replace */
-		memset(t->target.u.user.name, 0, FUNCTION_MAXNAMELEN);
+		memset(t->target.u.user.name, 0, XT_EXTENSION_MAXNAMELEN);
 		strcpy(t->target.u.user.name, STANDARD_TARGET);
+		t->target.u.user.revision = 0;
 		/* Jumps can only happen to builtin chains, so we
 		 * can safely assume that they always have a header */
 		t->verdict = r->jump->head_offset + IPTCB_CHAIN_START_SIZE;
@@ -1676,8 +1677,9 @@ iptcc_standard_map(struct rule_head *r, int verdict)
 		return 0;
 	}
 	/* memset for memcmp convenience on delete/replace */
-	memset(t->target.u.user.name, 0, FUNCTION_MAXNAMELEN);
+	memset(t->target.u.user.name, 0, XT_EXTENSION_MAXNAMELEN);
 	strcpy(t->target.u.user.name, STANDARD_TARGET);
+	t->target.u.user.revision = 0;
 	t->verdict = verdict;
 
 	r->type = IPTCC_R_STANDARD;
-- 
2.21.0