From 1d10760c9f9bdede3b9a8a13a739fd5915aa2b19 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Wed, 21 Aug 2024 14:20:03 +1000 Subject: conf: Move DNS array bounds checks into add_dns[46] 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 Signed-off-by: Stefano Brivio --- conf.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/conf.c b/conf.c index d19013c..dfe417b 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; } -- cgit v1.2.3