From: David Gibson <david@gibson.dropbear.id.au>
To: passt-dev@passt.top, Stefano Brivio <sbrivio@redhat.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Subject: [PATCH 08/16] conf: Move DNS array bounds checks into add_dns[46]
Date: Wed, 14 Aug 2024 14:30:42 +1000 [thread overview]
Message-ID: <20240814043050.4177037-9-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <20240814043050.4177037-1-david@gibson.dropbear.id.au>
Every time we call add_dns[46] we need to first check if there's space in
the c->ip[46].dns array for the new entry. We might as well make that
check in add_dns[46]() itself.
In fact it looks like the calls in get_dns() had an off by one error, not
allowing the last entry of the array to be filled. So, that bug is also
fixed by the change.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
conf.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)
diff --git a/conf.c b/conf.c
index db036a75..a651cb91 100644
--- a/conf.c
+++ b/conf.c
@@ -363,6 +363,9 @@ static unsigned add_dns4(struct ctx *c, const struct in_addr *addr,
{
unsigned added = 0;
+ if (idx >= ARRAY_SIZE(c->ip4.dns))
+ return 0;
+
/* Guest or container can only access local addresses via redirect */
if (IN4_IS_ADDR_LOOPBACK(addr)) {
if (!c->no_map_gw) {
@@ -395,6 +398,9 @@ static unsigned add_dns6(struct ctx *c, struct in6_addr *addr, unsigned idx)
{
unsigned added = 0;
+ if (idx >= ARRAY_SIZE(c->ip6.dns))
+ return 0;
+
/* Guest or container can only access local addresses via redirect */
if (IN6_IS_ADDR_LOOPBACK(addr)) {
if (!c->no_map_gw) {
@@ -453,12 +459,10 @@ static void get_dns(struct ctx *c)
if (end)
*end = 0;
- if (!dns4_set && dns4_idx < ARRAY_SIZE(c->ip4.dns) - 1
- && inet_pton(AF_INET, p + 1, &dns4_tmp))
+ if (!dns4_set && inet_pton(AF_INET, p + 1, &dns4_tmp))
dns4_idx += add_dns4(c, &dns4_tmp, dns4_idx);
- if (!dns6_set && dns6_idx < ARRAY_SIZE(c->ip6.dns) - 1
- && inet_pton(AF_INET6, p + 1, &dns6_tmp))
+ if (!dns6_set && inet_pton(AF_INET6, p + 1, &dns6_tmp))
dns6_idx += add_dns6(c, &dns6_tmp, dns6_idx);
} else if (!dnss_set && strstr(line, "search ") == line &&
s == c->dns_search) {
@@ -1682,14 +1686,12 @@ void conf(struct ctx *c, int argc, char **argv)
c->no_dns = 0;
- if (dns4_idx < ARRAY_SIZE(c->ip4.dns) &&
- inet_pton(AF_INET, optarg, &dns4_tmp)) {
+ if (inet_pton(AF_INET, optarg, &dns4_tmp)) {
dns4_idx += add_dns4(c, &dns4_tmp, dns4_idx);
continue;
}
- if (dns6_idx < ARRAY_SIZE(c->ip6.dns) &&
- inet_pton(AF_INET6, optarg, &dns6_tmp)) {
+ if (inet_pton(AF_INET6, optarg, &dns6_tmp)) {
dns6_idx += add_dns6(c, &dns6_tmp, dns6_idx);
continue;
}
--
@@ -363,6 +363,9 @@ static unsigned add_dns4(struct ctx *c, const struct in_addr *addr,
{
unsigned added = 0;
+ if (idx >= ARRAY_SIZE(c->ip4.dns))
+ return 0;
+
/* Guest or container can only access local addresses via redirect */
if (IN4_IS_ADDR_LOOPBACK(addr)) {
if (!c->no_map_gw) {
@@ -395,6 +398,9 @@ static unsigned add_dns6(struct ctx *c, struct in6_addr *addr, unsigned idx)
{
unsigned added = 0;
+ if (idx >= ARRAY_SIZE(c->ip6.dns))
+ return 0;
+
/* Guest or container can only access local addresses via redirect */
if (IN6_IS_ADDR_LOOPBACK(addr)) {
if (!c->no_map_gw) {
@@ -453,12 +459,10 @@ static void get_dns(struct ctx *c)
if (end)
*end = 0;
- if (!dns4_set && dns4_idx < ARRAY_SIZE(c->ip4.dns) - 1
- && inet_pton(AF_INET, p + 1, &dns4_tmp))
+ if (!dns4_set && inet_pton(AF_INET, p + 1, &dns4_tmp))
dns4_idx += add_dns4(c, &dns4_tmp, dns4_idx);
- if (!dns6_set && dns6_idx < ARRAY_SIZE(c->ip6.dns) - 1
- && inet_pton(AF_INET6, p + 1, &dns6_tmp))
+ if (!dns6_set && inet_pton(AF_INET6, p + 1, &dns6_tmp))
dns6_idx += add_dns6(c, &dns6_tmp, dns6_idx);
} else if (!dnss_set && strstr(line, "search ") == line &&
s == c->dns_search) {
@@ -1682,14 +1686,12 @@ void conf(struct ctx *c, int argc, char **argv)
c->no_dns = 0;
- if (dns4_idx < ARRAY_SIZE(c->ip4.dns) &&
- inet_pton(AF_INET, optarg, &dns4_tmp)) {
+ if (inet_pton(AF_INET, optarg, &dns4_tmp)) {
dns4_idx += add_dns4(c, &dns4_tmp, dns4_idx);
continue;
}
- if (dns6_idx < ARRAY_SIZE(c->ip6.dns) &&
- inet_pton(AF_INET6, optarg, &dns6_tmp)) {
+ if (inet_pton(AF_INET6, optarg, &dns6_tmp)) {
dns6_idx += add_dns6(c, &dns6_tmp, dns6_idx);
continue;
}
--
2.46.0
next prev parent reply other threads:[~2024-08-14 4:31 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-14 4:30 [PATCH 00/16] Cleanups and fixes related to "our" addresses David Gibson
2024-08-14 4:30 ` [PATCH 01/16] conf: Don't ignore -t and -u options after -D David Gibson
2024-08-14 12:18 ` Stefano Brivio
2024-08-14 4:30 ` [PATCH 02/16] treewide: Use "our address" instead of "forwarding address" David Gibson
2024-08-14 4:30 ` [PATCH 03/16] util: Helper for formatting MAC addresses David Gibson
2024-08-14 4:30 ` [PATCH 04/16] treewide: Rename MAC address fields for clarity David Gibson
2024-08-14 4:30 ` [PATCH 05/16] treewide: Use struct assignment instead of memcpy() for IP addresses David Gibson
2024-08-14 4:30 ` [PATCH 06/16] conf: Use array indices rather than pointers for DNS array slots David Gibson
2024-08-14 4:30 ` [PATCH 07/16] conf: More accurately count entries added in get_dns() David Gibson
2024-08-14 4:30 ` David Gibson [this message]
2024-08-14 4:30 ` [PATCH 09/16] conf: Move adding of a nameserver from resolv.conf into subfunction David Gibson
2024-08-14 4:30 ` [PATCH 10/16] conf: Correct setting of dns_match address in add_dns6() David Gibson
2024-08-14 4:30 ` [PATCH 11/16] conf: Treat --dns addresses as guest visible addresses David Gibson
2024-08-14 4:30 ` [PATCH 12/16] conf: Remove incorrect initialisation of addr_ll_seen David Gibson
2024-08-14 4:30 ` [PATCH 13/16] util: Correct sock_l4() binding for link local addresses David Gibson
2024-08-14 4:30 ` [PATCH 14/16] treewide: Change misleading 'addr_ll' name David Gibson
2024-08-14 4:30 ` [PATCH 15/16] Clarify which addresses in ip[46]_ctx are meaningful where David Gibson
2024-08-14 4:30 ` [PATCH 16/16] Initialise our_tap_ll to ip6.gw when suitable David Gibson
2024-08-14 4:39 ` David Gibson
2024-08-14 5:03 ` [PATCH 00/16] Cleanups and fixes related to "our" addresses David Gibson
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