| From 1171111657081970585f9f0e03b476358c33a6c0 Mon Sep 17 00:00:00 2001 |
| From: Mark Andrews <marka@isc.org> |
| Date: Wed, 12 Oct 2016 20:36:52 +0900 |
| Subject: [PATCH] |
| 4467. [security] It was possible to trigger an assertion when |
| rendering a message. (CVE-2016-2776) [RT #43139] |
| |
| Backport commit 2bd0922cf995b9ac205fc83baf7e220b95c6bf12 from the |
| v9.11.0_patch branch. |
| |
| CVE: CVE-2016-2776 |
| Upstream-Status: Backport |
| |
| Signed-off-by: zhengruoqin <zhengrq.fnst@cn.fujitsu.com> |
| |
| --- |
| CHANGES | 3 +++ |
| lib/dns/message.c | 42 +++++++++++++++++++++++++++++++----------- |
| 2 files changed, 34 insertions(+), 11 deletions(-) |
| |
| diff --git a/CHANGES b/CHANGES |
| index d0a9d12..5c8c61a 100644 |
| --- a/CHANGES |
| +++ b/CHANGES |
| @@ -1,3 +1,6 @@ |
| +4467. [security] It was possible to trigger an assertion when |
| + rendering a message. (CVE-2016-2776) [RT #43139] |
| + |
| 4406. [security] getrrsetbyname with a non absolute name could |
| trigger an infinite recursion bug in lwresd |
| and named with lwres configured if when combined |
| diff --git a/lib/dns/message.c b/lib/dns/message.c |
| index 6b5b4bb..b74dc81 100644 |
| --- a/lib/dns/message.c |
| +++ b/lib/dns/message.c |
| @@ -1754,7 +1754,7 @@ dns_message_renderbegin(dns_message_t *msg, dns_compress_t *cctx, |
| if (r.length < DNS_MESSAGE_HEADERLEN) |
| return (ISC_R_NOSPACE); |
| |
| - if (r.length < msg->reserved) |
| + if (r.length - DNS_MESSAGE_HEADERLEN < msg->reserved) |
| return (ISC_R_NOSPACE); |
| |
| /* |
| @@ -1895,8 +1895,29 @@ norender_rdataset(const dns_rdataset_t *rdataset, unsigned int options, |
| |
| return (ISC_TRUE); |
| } |
| - |
| #endif |
| + |
| +static isc_result_t |
| +renderset(dns_rdataset_t *rdataset, dns_name_t *owner_name, |
| + dns_compress_t *cctx, isc_buffer_t *target, |
| + unsigned int reserved, unsigned int options, unsigned int *countp) |
| +{ |
| + isc_result_t result; |
| + |
| + /* |
| + * Shrink the space in the buffer by the reserved amount. |
| + */ |
| + if (target->length - target->used < reserved) |
| + return (ISC_R_NOSPACE); |
| + |
| + target->length -= reserved; |
| + result = dns_rdataset_towire(rdataset, owner_name, |
| + cctx, target, options, countp); |
| + target->length += reserved; |
| + |
| + return (result); |
| +} |
| + |
| isc_result_t |
| dns_message_rendersection(dns_message_t *msg, dns_section_t sectionid, |
| unsigned int options) |
| @@ -1939,6 +1960,8 @@ dns_message_rendersection(dns_message_t *msg, dns_section_t sectionid, |
| /* |
| * Shrink the space in the buffer by the reserved amount. |
| */ |
| + if (msg->buffer->length - msg->buffer->used < msg->reserved) |
| + return (ISC_R_NOSPACE); |
| msg->buffer->length -= msg->reserved; |
| |
| total = 0; |
| @@ -2214,9 +2237,8 @@ dns_message_renderend(dns_message_t *msg) { |
| * Render. |
| */ |
| count = 0; |
| - result = dns_rdataset_towire(msg->opt, dns_rootname, |
| - msg->cctx, msg->buffer, 0, |
| - &count); |
| + result = renderset(msg->opt, dns_rootname, msg->cctx, |
| + msg->buffer, msg->reserved, 0, &count); |
| msg->counts[DNS_SECTION_ADDITIONAL] += count; |
| if (result != ISC_R_SUCCESS) |
| return (result); |
| @@ -2232,9 +2254,8 @@ dns_message_renderend(dns_message_t *msg) { |
| if (result != ISC_R_SUCCESS) |
| return (result); |
| count = 0; |
| - result = dns_rdataset_towire(msg->tsig, msg->tsigname, |
| - msg->cctx, msg->buffer, 0, |
| - &count); |
| + result = renderset(msg->tsig, msg->tsigname, msg->cctx, |
| + msg->buffer, msg->reserved, 0, &count); |
| msg->counts[DNS_SECTION_ADDITIONAL] += count; |
| if (result != ISC_R_SUCCESS) |
| return (result); |
| @@ -2255,9 +2276,8 @@ dns_message_renderend(dns_message_t *msg) { |
| * the owner name of a SIG(0) is irrelevant, and will not |
| * be set in a message being rendered. |
| */ |
| - result = dns_rdataset_towire(msg->sig0, dns_rootname, |
| - msg->cctx, msg->buffer, 0, |
| - &count); |
| + result = renderset(msg->sig0, dns_rootname, msg->cctx, |
| + msg->buffer, msg->reserved, 0, &count); |
| msg->counts[DNS_SECTION_ADDITIONAL] += count; |
| if (result != ISC_R_SUCCESS) |
| return (result); |
| -- |
| 2.7.4 |
| |