From 0e3434aeb1eed951fdbeddacc6126e10d82a1c8b Mon Sep 17 00:00:00 2001 From: =?utf8?q?Stanis=C5=82aw=20Pitucha?= Date: Tue, 18 Nov 2014 14:52:13 +1100 Subject: [PATCH] resolve: reject empty TXT records TXT records should have at least one character, so enforce this. Before 0f84a72 parser SIGSEGV'd on ->txt.strings being NULL, but even if this is fixed we should reject invalid TXT records. --- src/resolve/resolved-dns-packet.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/src/resolve/resolved-dns-packet.c b/src/resolve/resolved-dns-packet.c index c587a5612..a9bd8b139 100644 --- a/src/resolve/resolved-dns-packet.c +++ b/src/resolve/resolved-dns-packet.c @@ -1114,6 +1114,13 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start) { case DNS_TYPE_TXT: { char *s; + /* RFC 1035 says that TXT must be at least one + string. Reject empty records. */ + if (!rdlength) { + r = -EBADMSG; + goto fail; + } + while (p->rindex < offset + rdlength) { r = dns_packet_read_string(p, &s, NULL); if (r < 0) -- 2.30.2