From 8ac8129d710b8a084ce213791874330aa30ec70e Mon Sep 17 00:00:00 2001
From: Andrea Claudi <aclaudi@redhat.com>
Date: Mon, 29 Apr 2019 20:08:08 +0200
Subject: [PATCH] tc/m_xt: Fix for potential string buffer overflows

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1465646
Upstream Status: iproute2.git commit 56270e54661e8

commit 56270e54661e8ca51d4b3661b9f9bb12a0a40d95
Author: Phil Sutter <phil@nwl.cc>
Date:   Thu Aug 24 11:51:49 2017 +0200

    tc/m_xt: Fix for potential string buffer overflows

    - Use strncpy() when writing to target->t->u.user.name and make sure the
      final byte remains untouched (xtables_calloc() set it to zero).
    - 'tname' length sanitization was completely wrong: If it's length
      exceeded the 16 bytes available in 'k', passing a length value of 16
      to strncpy() would overwrite the previously NULL'ed 'k[15]'. Also, the
      sanitization has to happen if 'tname' is exactly 16 bytes long as
      well.

    Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 tc/m_xt.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/tc/m_xt.c b/tc/m_xt.c
index ad52d239caf61..9218b14594403 100644
--- a/tc/m_xt.c
+++ b/tc/m_xt.c
@@ -95,7 +95,8 @@ build_st(struct xtables_target *target, struct xt_entry_target *t)
 	if (t == NULL) {
 		target->t = xtables_calloc(1, size);
 		target->t->u.target_size = size;
-		strcpy(target->t->u.user.name, target->name);
+		strncpy(target->t->u.user.name, target->name,
+			sizeof(target->t->u.user.name) - 1);
 		target->t->u.user.revision = target->revision;
 
 		if (target->init != NULL)
@@ -277,8 +278,8 @@ static int parse_ipt(struct action_util *a, int *argc_p,
 	}
 	fprintf(stdout, " index %d\n", index);
 
-	if (strlen(tname) > 16) {
-		size = 16;
+	if (strlen(tname) >= 16) {
+		size = 15;
 		k[15] = 0;
 	} else {
 		size = 1 + strlen(tname);
-- 
2.21.0