From: Mark Andrews Date: Wed, 7 Jul 2021 04:08:04 +0000 (+1000) Subject: Silence tainted scalar on rdlen X-Git-Tag: v9.16.20~27^2 X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=ac34c3f55294bd41758e8b205555cf789a72e2e9;p=thirdparty%2Fbind9.git Silence tainted scalar on rdlen 2042 ttl = isc_buffer_getuint32(&j->it.source); 13. tainted_data_transitive: Call to function isc_buffer_getuint16 with tainted argument *j->it.source.base returns tainted data. [show details] 14. var_assign: Assigning: rdlen = isc_buffer_getuint16(&j->it.source), which taints rdlen. 2043 rdlen = isc_buffer_getuint16(&j->it.source); 2044 2045 /* 2046 * Parse the rdata. 2047 */ 15. Condition j->it.source.used - j->it.source.current != rdlen, taking false branch. 2048 if (isc_buffer_remaininglength(&j->it.source) != rdlen) { 2049 FAIL(DNS_R_FORMERR); 2050 } 16. var_assign_var: Assigning: j->it.source.active = j->it.source.current + rdlen. Both are now tainted. 2051 isc_buffer_setactive(&j->it.source, rdlen); 2052 dns_rdata_reset(&j->it.rdata); 17. lower_bounds: Checking lower bounds of unsigned scalar j->it.source.active by taking the true branch of j->it.source.active > j->it.source.current. CID 316506 (#1 of 1): Untrusted loop bound (TAINTED_SCALAR) 18. tainted_data: Passing tainted expression j->it.source.active to dns_rdata_fromwire, which uses it as a loop boundary. [show details] Ensure that tainted values are properly sanitized, by checking that their values are within a permissible range. 2053 CHECK(dns_rdata_fromwire(&j->it.rdata, rdclass, rdtype, &j->it.source, 2054 &j->it.dctx, 0, &j->it.target)); (cherry picked from commit f0fdca90f2baa3a8cc2e04fb47f367ef90486357) --- diff --git a/lib/dns/journal.c b/lib/dns/journal.c index f54ade5e8d5..7b355083fa4 100644 --- a/lib/dns/journal.c +++ b/lib/dns/journal.c @@ -2042,6 +2042,14 @@ read_one_rr(dns_journal_t *j) { ttl = isc_buffer_getuint32(&j->it.source); rdlen = isc_buffer_getuint16(&j->it.source); + if (rdlen > DNS_RDATA_MAXLENGTH) { + isc_log_write(JOURNAL_COMMON_LOGARGS, ISC_LOG_ERROR, + "%s: journal corrupt: impossible rdlen " + "(%u bytes)", + j->filename, rdlen); + FAIL(ISC_R_FAILURE); + } + /* * Parse the rdata. */