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